USB-1608FS-Plus-OEM
Analog and Digital I/O

User's Guide

Document Revision 2A
December 2014
© Copyright 2014

Trademark and Copyright Information
Measurement Computing Corporation, InstaCal, Universal Library, and the Measurement Computing logo areeither trademarks or registered trademarks of Measurement Computing Corporation. Refer to the Copyrights &Trademarks section on mccdaq.com/legal for more information about Measurement Computing trademarks.
Other product and company names mentioned herein are trademarks or trade names of their respective
companies.
© 2014 Measurement Computing Corporation. All rights reserved. No part of this publication may be
reproduced, stored in a retrieval system, or transmitted, in any form by any means, electronic, mechanical, by
photocopying, recording, or otherwise without the prior written permission of Measurement Computing
Corporation.
NoticeMeasurement Computing Corporation does not authorize any Measurement Computing Corporation product for
use in life support systems and/or devices without prior written consent from Measurement Computing
Corporation. Life support devices/systems are devices or systems that, a) are intended for surgical implantation
into the body, or b) support or sustain life and whose failure to perform can be reasonably expected to result ininjury. Measurement Computing Corporation products are not designed with the components required, and are
not subject to the testing required to ensure a level of reliability suitable for the treatment and diagnosis ofpeople.

HM USB-1608FS-Plus-OEM

Table of Contents
Preface

About this User's Guide ....................................................................................................................... 5
What you will learn from this user's guide ......................................................................................................... 5
Conventions in this user's guide ......................................................................................................................... 5
Where to find more information ......................................................................................................................... 5
Chapter 1

Introducing the USB-1608FS-Plus-OEM ............................................................................................. 6
Functional block diagram ................................................................................................................................... 7
Chapter 2

Installing a USB-1608FS-Plus-OEM ..................................................................................................... 8
Unpacking........................................................................................................................................................... 8
Downloading the software .................................................................................................................................. 8
Installing the hardware ....................................................................................................................................... 8
Installing on a Windows platform ..................................................................................................................................... 8
Installing on an Android platform ..................................................................................................................................... 8

Calibrating the hardware..................................................................................................................................... 8
Chapter 3

Functional Details ................................................................................................................................. 9
Analog input modes ............................................................................................................................................ 9
Software paced .................................................................................................................................................................. 9
Hardware paced ................................................................................................................................................................ 9
BURSTIO ......................................................................................................................................................................... 9

Board components ............................................................................................................................................ 10
USB connector .................................................................................................................................................................10
LED .................................................................................................................................................................................10
Header connectors............................................................................................................................................................11

Signal connections ............................................................................................................................................ 11
Analog input ....................................................................................................................................................................11
Channel-Gain queue ........................................................................................................................................................11
Digital I/O ........................................................................................................................................................................12
Pull-up/down configuration .............................................................................................................................................12Counter input ...................................................................................................................................................................13
SYNC I/O ........................................................................................................................................................................13
Trigger input ....................................................................................................................................................................13
Reserved ..........................................................................................................................................................................13
Ground .............................................................................................................................................................................13
Power output ....................................................................................................................................................................13

Accuracy ........................................................................................................................................................... 14
Synchronized operations................................................................................................................................... 16
Mechanical drawings ........................................................................................................................................ 16
Chapter 4

Specifications ...................................................................................................................................... 17
Analog input ..................................................................................................................................................... 17
Accuracy ........................................................................................................................................................... 17
Analog input DC voltage measurement accuracy ............................................................................................................17
Noise performance ...........................................................................................................................................................18

Digital input/output........................................................................................................................................... 18
External trigger ................................................................................................................................................. 19
External clock input/output............................................................................................................................... 19Counter section ................................................................................................................................................. 20
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USB-1608FS-Plus-OEM User's Guide

Memory ............................................................................................................................................................ 20
Microcontroller ................................................................................................................................................. 20
Power ................................................................................................................................................................ 21
General ............................................................................................................................................................. 21
Environmental .................................................................................................................................................. 21
Mechanical ....................................................................................................................................................... 21
Header connector and pinout ............................................................................................................................ 21

4

Preface

About this User's Guide
What you will learn from this user's guideThis user's guide describes the Measurement Computing USB-1608FS-Plus-OEM data acquisition device andlists device specifications.

Conventions in this user's guide
For more information
Text presented in a box signifies additional information and helpful hints related to the subject matter you arereading.
Caution! Shaded caution statements present information to help you avoid injuring yourself and others,
damaging your hardware, or losing your data.
bold text

Bold text is used for the names of objects on a screen, such as buttons, text boxes, and check boxes.

italic text

Italic text is used for the names of manuals and help topic titles, and to emphasize a word or phrase.

Where to find more information
Additional information about the USB-1608FS-Plus-OEM is available on our website at www.mccdaq.com.
You can also contact Measurement Computing Corporation with specific questions.


Knowledgebase: kb.mccdaq.com
Tech support form: www.mccdaq.com/support/support_form.aspx
Email: techsupport@mccdaq.com
Phone: 508-946-5100 and follow the instructions for reaching Tech Support

For international customers, contact your local distributor. Refer to the International Distributors section on our
website at www.mccdaq.com/International.

5Chapter 1

Introducing the USB-1608FS-Plus-OEM
The USB-1608FS-Plus-OEM is a USB 2.0 full-speed analog input and digital I/O data acquisition device
providing the following features:








Eight 16-bit single-ended (SE) analog input channels
Each input channel has a dedicated A/D converter for simultaneous sampling.
Software-selectable analog input ranges of ±10 V, ±5 V, ±2 V, and ±1 V
Eight individually configurable digital I/O channels
One 32-bit event counter
One external digital trigger input
Bidirectional external clock for synchronous operation with more than one device.
Two header connectors for field wiring connections

The USB-1608FS-Plus-OEM device is compatible with both USB 1.1 and USB 2.0 ports. The speed of thedevice may be limited when using a USB 1.1 port due to the difference in transfer rates on the USB 1.1 versionsof the protocol (low-speed and full-speed).
The device is powered by the +5V USB supply from the computer, requiring no external power.
Caution! There are no product safety, electromagnetic compatibility (EMC), or CE marking complianceclaims made for the USB-1608FS-Plus-OEM. The USB-1608FS-Plus-OEM is intended for use as
a component of a larger system. MCC can help developers meet their compliance requirements.
The end product supplier, however, is responsible for conforming to any and all compliancerequirements.

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USB-1608FS-Plus-OEM User's Guide

Introducing the USB-1608FS-Plus-OEM

Functional block diagram
USB-1608FS-Plus-OEM functions are illustrated in the block diagram shown here.

Figure 1. Functional block diagram

7

Chapter 2

Installing a USB-1608FS-Plus-OEM
UnpackingAs with any electronic device, you should take care while handling to avoid damage from static
electricity. Before removing the board from its packaging, ground yourself using a wrist strap or by simply
touching the computer chassis or other grounded object to eliminate any stored static charge.

Downloading the software
Refer to the USB-1608FS-Plus-OEM product page on the Measurement Computing website for information
about the supported software you can download.
Install the software before you install the hardware
The driver needed to run the device is installed when you install the software. Therefore, you need to install thesoftware package you plan to use before you install the hardware.

Installing the hardware
Installing on a Windows platform
Connect the USB-1608FS-Plus-OEM to a to an available USB port on the computer running Windows, connect
the USB cable to an available USB port on the computer or to an external USB hub connected to the computer.
Connect the other end of the cable to the USB connector on the device. No external power is required.
When connected for the first time, a Found New Hardware dialog opens when the operating system detects thedevice. When the dialog closes, the installation is complete. The device LED turns on after the device issuccessfully installed.
If the LED turns off
If communication is lost between the device and the computer, the LED turns off. To restore communication,
disconnect the USB cable from the computer and then reconnect it. This should restore communication, and the
LED should turn on.

Installing on an Android platform
Many Android devices include a standard A-type USB port to connect to the USB-1608FS-Plus-OEM. If yourdevice does not have a USB port, you may need a USB OTG cable in order for your Android device to host a
USB device. Refer to your Android device documentation for more information.

Calibrating the hardware
The Measurement Computing Manufacturing Test department performs the initial factory calibration. Returnthe device to Measurement Computing Corporation when calibration is required. The recommended calibrationinterval is one year.
Field calibration is not supported.

8

Chapter 3

Functional Details
Analog input modes
The USB-1608FS-Plus-OEM can acquire analog input data in three modes – software paced, hardware paced,and BURSTIO.

Software paced
You can acquire one analog sample at a time in software-paced mode. You initiate the A/D conversion bycalling a software command. The analog value is converted to digital data and returned to the computer. You
can repeat this procedure until you have the total number of samples that you want.
The USB-1608FS-Plus-OEM can attain throughput rates up to 500 S/s using a software loop. This rate issystem-dependent.

Hardware paced
The USB-1608FS-Plus-OEM can acquire data from up to eight channels simultaneously in hardware-paced
mode. The analog data is acquired, converted to digital values, and written to an onboard FIFO buffer on thedevice until you stop the scan. Data is transferred in blocks from the device to the memory buffer on yourcomputer.
The A/D converter is paced by either an internal or external clock source.
The maximum sampling rate is an aggregate rate. The total sample rate using hardware-paced mode is 400 kS/s
divided by the number of channels, with a maximum rate of 100 kS/s for any channel. You can acquire datafrom one to four channels at 100 kS/s each, six channels at 66.7 kS/s each, and so on, up to eight channels at
50 kS/s each. You can start a hardware-paced scan with a software command. Optionally, hardware-paced scans
can be delayed by an external hardware trigger event.
BURSTIO
When using BURSTIO, the USB-1608FS-Plus-OEM can acquire data at a higher rate using the full capacity of
the 32 kilosample FIFO. The acquired data is read from the FIFO and transferred to a user buffer in thecomputer after the acquisition is complete. You can initiate a single acquisition sequence of one to eightchannels with a software command. Optionally, BURSTIO scans can be delayed by an external hardware
trigger event.
When BURSTIO is enabled, the number of samples acquired in a scan is limited to the depth of the onboard
memory. The maximum sample rate in BURSTIO mode is an aggregate rate of 800 kS/s. The maximum perchannel sample rate is 100 kS/s for any or all channels.

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USB-1608FS-Plus-OEM User's Guide

Functional Details

Board components
Board components are shown in Figure 2.

1
2

Header connectors 21 to 40
LED

3
4

USB connector
Header connectors 1 to 20

Figure 2. Board components

USB connector
Receives the supplied USB cable. When connected to a computer or USB hub, the cable provides +5 V powerand communication. No external power supply is required.

LED
The LED indicates the USB communication status; it cannot be disabled.
LED behavior
LED state

Indication

On – steady green
Blinks once
Blinks continuously

The device is connected to a computer or external USB hub.
A USB command is received.
An analog input scan is in progress.

10USB-1608FS-Plus-OEM User's Guide

Functional Details

Header connectors
The header connectors provide connections for the analog inputs, analog ground, DIO, clock I/O, trigger,
counter, power output, and digital ground reference.
Header connector pinout (refer to Figure 2 for pin numbering)Pin

Signal Description

Signal Name

Pin

Signal Description

Signal Name

40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21

Digital ground
Power output
Counter input
Trigger input
Sync I/O
DIO channel 7
Digital ground
DIO channel 6
Digital ground
DIO channel 5
Digital ground
DIO channel 4
Digital ground
DIO channel 3
Digital ground
DIO channel 2
Digital ground
DIO channel 1
Digital ground
DIO channel 0

GND
+VO
CTR
TRIG_IN
SYNC
DIO7
GND
DIO6
GND
DIO5
GND
DIO4
GND
DIO3
GND
DIO2
GND
DIO1
GND
DIO0

AGND
AGND
AGND
RSVD
AGND
CH7 INAGND
CH6 INAGND
CH5 IN
AGND
CH4 IN
AGND
CH3 INAGND
CH2 INAGND
CH1 INAGND
CH0 IN

Analog ground
Analog ground
Analog groundReserved
Analog groundAI channel 7
Analog groundAI channel 6
Analog groundAI channel 5
Analog groundAI channel 4
Analog groundAI channel 3
Analog groundAI channel 2
Analog groundAI channel 1
Analog groundAI channel 0

20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1

USB connector

Signal connections
Analog input
You can connect up to eight analog input connections to the header connector containing pins 1 to 20 (CH0 IN
through CH7 IN.) Connect unused analog inputs to ground connectors during operation. For example, if you are
not using CH7 IN, ground this connector to AGND.
All analog input channels are configured for single-ended input mode. All analog input signals are referenced to
ground (AGND):


Connect the wire carrying the signal to be measured to CH# IN.
Connect the second wire to AGND.

The input voltage ranges are ±10 V, ±5 V, ±2.0 V, ±1.0 V.
For more information on analog signal connections
For more information on single-ended inputs, refer to the Guide to Signal Connections (this document isavailable on our web site at www.mccdaq.com/signals/signals.pdf).
Channel-Gain queue
The channel-gain queue feature allows you to configure a different gain setting for each channel. The gain
settings are stored in a channel-gain queue list that is written to local memory on the device.
The channel-gain queue list can contain up to eight unique elements. The channel list must be in increasingorder. An example of a five element list is shown in the table below.

11USB-1608FS-Plus-OEM User's Guide

Functional Details

Sample channel-gain queue list
Element

Channel

Range

0
1
2
3
4

CH0
CH2
CH4
CH6
CH7

BIP1V
BIP2V
BIP10V
BIP1V
BIP5V

Carefully match the gain to the expected voltage range on the associated channel or an over range condition
may occur. Although this condition does not damage the device, it does produce a useless full-scale reading,and can introduce a long recovery time due to saturation of the input channel.

Digital I/O
You can connect up to eight digital I/O lines to DIO0 through DIO7. Each digital channel is individuallyconfigurable for input or output. During initial power on or reset the digital pins are set for input.
The digital I/O terminals can detect the state of any TTL-level input. Refer to the schematic shown in Figure 3.

Figure 3. Schematic showing switch detection by digital channel DIO0

If you set the switch to the +5 V input, DIO0 reads TRUE (1). When set to GND, DIO0 reads FALSE (0).
Pull-up/down configuration
All digital I/O lines are pulled up to USB +5V (HI) with a 47 kΩ resistor (default). You can change thepull-up/down configuration using the internal jumper labeled DIO. You must remove the device housing toaccess the jumper on the circuit board.
To set the jumper for pull-up or pull-down, complete the following steps.
1.
2.

Unplug the device from the computer.
Turn the device over and rest the top of the housing on a flat, stable surface.

Caution! The discharge of static electricity can damage some electronic components. Before removing theUSB-1608FS-Plus-OEM from its housing, ground yourself using a wrist strap or touch thecomputer chassis or other grounded object to eliminate any stored static charge.
3.
4.

Remove the three screws from the bottom of the device using a #1 Philips head screwdriver.
Hold both the top and bottom sections together, turn the device over and rest it on the surface, thencarefully remove the top section of the case to expose the circuit board.
Figure 4 shows the location of the DIO jumper on the circuit board.

Figure 4. Pull-up/down jumper location

5.

Configure the jumper for pull-up or pull-down, as shown in Figure 5.
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USB-1608FS-Plus-OEM User's Guide

Functional Details

Figure 5. Pull-up/down jumper configuration

6.

Replace the top section of the housing, and fasten it to the bottom section with the three screws.

For more information on digital signal connections
For general information regarding digital signal connections and digital I/O techniques, refer to the Guide to
Signal Connections (available on our web site at www.mccdaq.com/signals/signals.pdf).

Counter input
The CTR connector is a 32-bit event counter that can accept frequency inputs up to 1 MHz. The internal counterincrements when the TTL levels transition from low to high.

SYNC I/O
The SYNC connector is a bidirectional I/O signal that can be configured as an input (default) or an output.
Configure as an external clock input to pace the A/D conversions from an external source. The SYNC
connector supports TTL-level input signals of up to 100 kHz.
Configure as an output that may be used to pace conversions on a second device and acquire data from16 channels. Refer to page 16 for more information about synchronized operations.

Trigger input
The TRIG_IN connector is an external digital trigger input. The trigger mode is software-selectable for edge orlevel sensitive. Edge sensitive mode is selectable for rising or falling. Level sensitive mode is selectable forhigh or low.

Reserved
The RSVD connector is reserved for future use.

GroundThe analog ground (AGND) connectors provide a common ground for all analog channels.
The digital ground (GND) connectors provide a common ground for the digital, trigger, counter, and sync
channels and the power connector.

Power output
The PC +5V output connector can output up to 200 mA maximum. You can use this connector to supply power
to external devices or circuitry.
Caution! The PC +5V connector is an output. Do not connect it to an external power supply or you may
damage the device and possibly the computer.
The maximum output current that can be drawn by the USB-1608FS-Plus-OEM is 500 mA. This maximum
applies to most personal computers and self-powered USB hubs. Bus-powered hubs and notebook computers
may limit the maximum available output current to 100 mA. If the current requirement of the device exceeds
the current available from the computer, connect to a self-powered hub or power the computer with an external
power adapter.
When running applications with the device, each DIO bit can source up to 24 mA. The total amount of current
that can be sourced from the PC +5V, SYNC, and digital outputs is 200 mA max.
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USB-1608FS-Plus-OEM User's Guide

Functional Details

Accuracy
The overall accuracy of any instrument is limited by the error components within the system. Resolution isoften used incorrectly to quantify the performance of a measurement product. While "16-bits" or "1 part in
65,536" does indicate what can be resolved, it provides little insight into the quality, or accuracy, of an absolutemeasurement.
Accuracy specifications describe the actual measurement achievable with a USB-1608FS-Plus-OEM. Accuracy
specifications are listed on page 17.
There are three types of errors which affect the accuracy of a measurement system:

offsetgain
nonlinearity

The primary error sources in a USB-1608FS-Plus-OEM are offset and gain. Nonlinearity is small, and is not
significant as an error source with respect to offset and gain.
Figure 6 shows an ideal, error-free transfer function. The typical calibrated accuracy of a USB-1608FS-PlusOEM is range-dependent. We use a ±10 V range as an example of what you can expect when performing ameasurement in this range.

Figure 6. Ideal ADC transfer function

The offset error is measured at mid-scale. Ideally, a zero volt input should produce an output code of 32,768.
Any deviation from this is an offset error. Figure 7 shows the transfer function with an offset error. The typicaloffset error specification for a USB-1608FS-Plus-OEM on the ±10 V range is ±1.66 mV. Offset error affects allcodes equally by shifting the entire transfer function up or down along the input voltage axis.
The accuracy plots in Figure 7 are drawn for clarity and are not drawn to scale.

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USB-1608FS-Plus-OEM User's Guide

Functional Details

Figure 7. ADC transfer function with offset error

Gain error is a change in the slope of the transfer function from the ideal, and is typically expressed as apercentage of full-scale. Figure 8 shows the USB-1608FS-Plus-OEMtransfer function with gain error. Gainerror is easily converted to voltage by multiplying the full-scale input (±10 V) by the error.
The accuracy plots in Figure 8 are drawn for clarity and are not drawn to scale.

Figure 8. ADC Transfer function with gain error

For example, a USB-1608FS-Plus-OEM exhibits a typical calibrated gain error of ±0.04% on all ranges. For the±10 V range, this would yield 10 V × ±0.0002 = ±4 mV. This means that at full scale, neglecting the effect ofoffset for the moment, the measurement would be within 4 mV of the actual value. Note that gain error isexpressed as a ratio. Values near ±FS (±10 V) are more affected from an absolute voltage standpoint than arevalues near mid-scale, which see little or no voltage error.
Combining these two error sources in Figure 9, we have a plot of the error band at ±full scale (±10 V). This plot
is a graphical version of the typical accuracy specification of the product.
The accuracy plots in Figure 9 are drawn for clarity and are not drawn to scale.

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USB-1608FS-Plus-OEM User's Guide

Functional Details

Figure 9. Error band plot

Synchronized operations
You can connect the SYNC pin of multiple devices together in a master/slave configuration and acquire datafrom the analog inputs of all devices using one clock.
When the SYNC pin is configured as an output, the internal A/D pacer clock signal is sent to the header
connector. You can output the clock to the SYNC pin of another device that is configured for A/D pacer input.

Mechanical drawings

Figure 10. USB-1608FS-Plus-OEM circuit board dimensions

16

Chapter 4

Specifications
All specifications are subject to change without notice.
Typical for 25°C unless otherwise specified.
Specifications in italic text are guaranteed by design.

Analog input
Table 1. General analog input specifications
Parameter
A/D converter type
Number of channels
Input configuration
Sampling method
Absolute maximum input voltage
Input impedance
Input ranges
Sampling rate
Throughput

Condition

Specification

BURSTIO ≤ 32,768 total samples(uses onboard FIFO)

16-bit successive approximation type8 single-ended
Individual A/D per channel
Simultaneous±15 V max
100 MΩ min±10 V, ±5 V, ±2 V, ±1 V
0.01 S/s to 100 kS/s, software-selectable
500 S/s all channels(400 kS/s) / (# of channels) max,
100 kS/s max for any channel(800 kS/s) / (# of channels) max,
100 kS/s max for any channel

Signal DC to 25 kHz
Software-selectable

Software configurable. Up to eightelements – one gain element per unique,ordered channel.
16 bits
16 bits–80 dB
External digital: TRIG_IN

CHx IN relative to GND
Software-selectable per channel
Hardware paced
Software paced
Hardware paced (Note 1)

Gain queue

Resolution
No missing codes
Crosstalk
Trigger source

Note 1: Maximum throughput when scanning in hardware paced mode is machine dependent.

Accuracy
Analog input DC voltage measurement accuracy
Table 2. Calibrated absolute accuracy
Range

Accuracy (mV)

±10 V
±5 V
±2 V
±1 V

5.66
2.98
1.31
0.68

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USB-1608FS-Plus-OEM User's Guide

Specifications

Table 3. Accuracy components - All values are (±)
Range

Gain error(% of Reading)Gain error at FS(mV)

Offset (mV)

±10 V
±5 V
±2 V
±1 V

0.04
0.04
0.04
0.04

4.00
2.00
0.80
0.40

1.66
0.98
0.51
0.28

Noise performance
Table 4. Noise performance
Range

Typical counts

LSBrms

±10 V
±5 V
±2 V
±1 V

10
10
11
14

1.52
1.52
1.67
2.12

Table 4 summarizes the noise performance for the USB-1608FS-Plus-OEM. Noise distribution is determined bygathering 50 K samples with inputs tied to ground at the user connector. Samples are gathered at the maximum
specified sampling rate of 100 kS/s.

Digital input/output
Table 5. Digital I/O specifications
Parameter

Specification

Digital type
Number of I/O
Configuration
Pull-up/pull-down
configuration

5V TTL
8 (DIO0 through DIO7)
Independently configured for input or output
All pins pulled up to 5V via 47 K resistors (default).
May be changed to pull-down using an internal jumper.
2.0 V min

Input high voltage
thresholdInput high voltage limit
Input low voltage
threshold

5.5 V absolute max
0.8 V max

Input low voltage limit–0.5 V absolute min
0 V recommended min
4.4 V min (IOH = –50 µA)
3.76 V min (IOH = –24 mA)
0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 24 mA)
Input

Output high voltage
Output low voltage
Power on and reset state18

USB-1608FS-Plus-OEM User's Guide

Specifications

External trigger
Table 6. External trigger specifications
Parameter

Condition

Specification

Trigger source
Trigger mode

External digital
Software-selectable

TRIG_IN
Edge or level sensitive: user configurable for CMOS
compatible rising or falling edge, high or low level.
2 µs + 1 pacer clock cycle max
1µs minSchmitt trigger, 47 kΩ pull-down to ground1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min3.1V max
5.5 V absolute max
1.42 V typ
1.0 V min
2.0 V max
-0.5 V absolute min
0 V recommended min

Trigger latency
Trigger pulse width
Input type
Schmitt trigger hysteresis

Input high voltage threshold

Input high voltage limit
Input low voltage threshold

Input low voltage limit

External clock input/output
Table 7. External clock I/O specifications
Parameter
Pin name
Pin type
Direction, software-selectable
Input clock rate
Clock pulse width
Input clock mode
Input type
Schmitt trigger hysteresis

Input high voltage threshold

Input high voltage limit
Input low voltage threshold

Input low voltage limit
Output high voltage
Output low voltage

Condition

Input
OutputInput
OutputSpecification
SYNC
Bidirectional
Receives A/D pacer clock from external source
Outputs internal A/D pacer clock
100 kHz, max
1 µs min4 µs minEdge sensitive, rising
Schmitt trigger, 47 kΩ pull-down to ground1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min3.1V max
5.5 V absolute max
1.42 V typ
1.0 V min
2.0 V max
-0.5 V absolute min
0 V recommended min
4.4 V min (IOH = –50 µA)
3.80 V min (IOH = –8 mA)
0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 8 mA)

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USB-1608FS-Plus-OEM User's Guide

Specifications

Counter section
Table 8. Counter specifications
Parameter

Specification

Pin name
Counter type
Number of channels
Input type
Input source
Resolution
Schmitt trigger hysteresis

CTR
Event counter
1
Schmitt trigger, 47 kΩ pull-down to ground
CTR header pin
32 bits
1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min3.1V max
5.5 V absolute max
1.42 V typ
1.0 V min
2.0 V max
-0.5 V absolute min
0 V recommended min
1 MHz max
500 ns min
500 ns min

Input high voltage threshold

Input high voltage limit
Input low voltage threshold

Input low voltage limit
Input frequency
High pulse width
Low pulse width

MemoryTable 9. Memory specifications
Parameter

Specification

Data FIFOEEPROM

32,768 samples, 65,536 bytes
2,048 bytes (768 bytes calibration, 256 bytes user, 1,024 bytes DAQFlex)

Microcontroller
Table 10. Microcontroller specifications
Parameter

Specification

Type

High performance 32-bit RISC microcontroller

20USB-1608FS-Plus-OEM User's Guide

Specifications

Power
Table 11. Power specifications
Parameter

Condition

Specification

Supply current
Supply current+5V power available (Note 2)

USB enumeration
Including DIO and SYNC output loading
Connected to externally-powered root port hub or aself-powered hub< 100 mA
< 500 mA
4.5 V min, 5.25 V max

Output current (Note 3)

200 mA max

Note 2: "Self-powered hub" refers to a USB hub with an external power supply. Self-powered hubs allow aconnected USB device to draw up to 500 mA. "Root port hubs" reside in the PC USB host Controller.
The USB port(s) on your PC are root port hubs. All externally-powered root port hubs, such as a
desktop PC, provide up to 500 mA of current for a USB device. Battery-powered root port hubs
provide 100 mA or 500 mA, depending upon the manufacturer. A laptop PC that is not connected to an
external power adapter is an example of a battery-powered root port hub. If your laptop PC isconstrained to the 100 mA maximum, you need to purchase a self-powered hub.
Note 3: Output current is the total amount of current that can be sourced from the PC +5V, SYNC, and digital
outputs.

GeneralTable 12. General specifications
Parameter

Specification

Device type
Device compatibility

USB 2.0 (full-speed)
USB 1.1, USB 2.0

Environmental
Table 13. Environmental specifications
Parameter

Specification

Operating temperature range
Storage temperature range
Humidity

0 °C to 70 °C–40 °C to 70 °C
0% to 90% non-condensing

Mechanical
Table 14. Mechanical specifications
Parameter

Specification

Dimensions (L × W × H)
USB cable length
User connection length

81.28 × 73.66 × 15.24 mm (3.20 × 2.9 × 0.6 in.)3 m (9.84 ft) max
3 m (9.84 ft) max

Header connector and pinout
Table 15. Connector specifications
Parameter

Specification

Connector typeTwo 20-pin, 0.1 in. pitch headers21

USB-1608FS-Plus-OEM User's Guide

Specifications

Table 16. Header connectors
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

Signal Name
CH0 INAGND
CH1 INAGND
CH2 IN
AGND
CH3 IN
AGND
CH4 INAGND
CH5 INAGND
CH6 INAGND
CH7 IN
AGND
RSVD
AGND
AGND
AGND

Pin
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40

Signal Name
DIO0
GND
DIO1
GND
DIO2
GND
DIO3
GND
DIO4
GND
DIO5
GND
DIO6
GND
DIO7
SYNC
TRIG_IN
CTR
+VO
GND

22

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