SHF Communication Technologies AG
Wilhelm-von-Siemens-Str. 23D • 12277 Berlin • Germany
Phone +49 30 772 051-0 • Fax +49 30 753 10 78
E-Mail: sales@shf-communication.com • Web: www.shf-communication.com

Datasheet
SHF F840 A
Differential Linear Broadband Amplifier

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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Description
The SHF F840 A is a RoHS- compliant differential linear amplifier designed for high data rate NRZ andPAM4 (16QAM) applications. The differential output amplitude of up to at least 4 V linear is well suited todrive differential-drive modulators at baud rates of up to at least 80 GBaud.
The SHF F840 A is optimized for differential drive and amplifies both inputs with a common gain circuitry
to have the output amplitude and the propagation delay of both outputs most equal. The two inputs
cannot be used single-ended i.e. both, the signal and the inverted signal have always to be applied tothe amplifier.
Like other SHF amplifiers this driver is supposed for use in an RF laboratory environment and enjoys thebenefit of an internal voltage regulation to protect against accidental reverse voltage connection.

Ease of Use
Upon delivery, the amplifier is already pre-set to deliver maximum gain and maximum bandwidth. Thesesettings can be modified in an easy to use graphical software interface, as shown below. For connecting
the amplifier to the computer, the USB to I2C converter cable is included with each amplifier at no extra
charge.
Once new settings are stored on the device the amplifier will remember the settings until further
changes are made. There is no need to connect a computer to the device unless gain and bandwidth
adjustments are to be made.
The software is available for download at www.shf-communication.com/software .

GUI of the SHF Amplifier Control software V1.6

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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Available Options
04:

Built-in bias tee on output (max. ±9 V, max. 200 mA, each path)1

DHS: Dual Heat Sink, two amplifiers on one heatsink

Applications

1•Optical Communications•High-Speed Pulse Experiments•

Satellite Communications•

Research and Development•

Data Transmission studies for 100 Gbps (100GbE), 200 Gbps (200GbE), 400 Gbps (400GbE) &1 Tbps (TbE) system evaluation•

Broadband test and measurement equipment•

PAM4 and Advanced Modulation Experiments

In case a bias tee option is chosen it may impact the specifications. Gain and output power might be reduced by up to 1 dB.
The low frequency 3 dB Point might be increased up to 100 kHz. The DC resistance of a bias tee isabout 6 Ω. There is a separate DC path for each output.

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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Specifications – SHF F840 AParameter

UnitSymboldBm

Pin maxMin

TypMaxConditions

Absolute Maximum Ratings
Maximum Single Ended
RF Input Signal

0each input porteach input port

V

0.7

DC Voltage at RF Input

V±2

AC coupled input

DC Voltage at RF Output

V±9

AC coupled output

Supply Voltage

V

129 V recommendedCase Temperature2°C

8Tcase1040

peak-to-peak input voltage

50

Electrical Characteristics (At 40°C case temperature, unless otherwise specified)High Frequency 3 dB
Point3GHzfHIGH

Low Frequency 3 dB Point3kHzfLOW

Gain3dB

S21

Max. Gain Reduction4dBdBm

Maximum Single EndedOutput Signal4

P55
70
10

11

differential out/differential in-1.5-2control via software interface

10

each output porteach output port

V

2

Maximum Differential
Output Voltage

V

4

Common Mode Rejection
RatiodB

CMRR

t.b.d.

Differential Output Skew

pstskew

t.b.d.

JitterfsJRMS

460
550

Power ConsumptionW

peak-to-peak output voltagepeak-to-peak output voltage

580
650

3.6

deconvoluted5,6
full setup5
i.e. 0.4 A @ 9 V supply voltage

2If operated with heat sink (part of the delivery) at room temperature there is no need for additional cooling.

3

Measured with an active 70 GHz balun at the inputs and a passive balun at the outputs.

4

Measured with a SHF 604 A power mux at the inputs

5

Measured with the following setup: SHF 616 A PAM-MUX -> DUT (SHF F840 A) -> Tektronix DSA 8300 with 70 GHz sampling
module (80E11) and phase reference module (82A04B-60G).
62𝐽𝑅𝑀𝑆 𝑑𝑒𝑐𝑜𝑛𝑣𝑜𝑙𝑢𝑡𝑒𝑑 = √(𝐽𝑅𝑀𝑆 𝑓𝑢𝑙𝑙 𝑠𝑒𝑡𝑢𝑝 )2 − (𝐽𝑅𝑀𝑆 𝑠𝑒𝑡𝑢𝑝 𝑤/𝑜 𝐷𝑈𝑇 ) = √(𝐽𝑅𝑀𝑆 𝑓𝑢𝑙𝑙 𝑠𝑒𝑡𝑢𝑝 )2 − 300 𝑓𝑠 2

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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Parameter

UnitSymbol

MinTypMax

Conditions

Mechanical Characteristics
Input Connectors

1.85 mm (V) female

Output Connectors

1.85 mm (V) female

Dimensions

Weightmmgsee page 10 to 1245255
320

without heat sinkwith single heat sink
DHS: two amplifier on one heat sink

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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Typical Differential Frequency Response7

7 Measured with an active 70 GHz balun at the inputs and a passive balun at the outputs

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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Typical Differential 4-Level Waveforms
The measurements below had been performed using a SHF 12104 A Bit Pattern Generator(PRBS 231-1), a SHF 616 A PAM-MUX and a Tektronix DSA 8300 Digital Serial Analyzer (DSA) with
Phase Reference Module (82A04B-60G), 70 GHz Sampling Module (80E11), 60 mm semi-rigid cablebetween SHF 616 A and F840 A and 60 mm semi-rigid cable between F840 A and Sampling Module.
The Amplifier was measured with 10 dB Attenuators between the outputs and the Sampling Module.
Gain and Bandwidth of the amplifier was set to maximum.
The screen shots were taken by using the math function of the scope to display the sum of the single
ended input- and output signals.
The measurement at 60 GBaud will be part of the inspection report delivered with each particulardevice.

Input Signal @ 90 GBaud,Amplitude: 688 mV

Output Signal @ 90 GBaud,Amplitude: 2.24 V

Input Signal @ 60 GBaud,Amplitude: 737 mV

Output Signal @ 60 GBaud,Amplitude: 2.67 V

Input Signal @ 30 GBaud,Amplitude: 739 mV

Output Signal @ 30 GBaud,
Amplitude: 2.81 V

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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Typical Differential Binary Waveforms (Low Voltage Drive)
The measurements below had been performed using a SHF 12104 A Bit Pattern Generator(PRBS 231-1), a SHF 616 A PAM-MUX and a Tektronix DSA 8300 Digital Serial Analyzer (DSA) with
Phase Reference Module (82A04B-60G), 70 GHz Sampling Module (80E11), 60 mm semi-rigid cablebetween SHF 616 A and F840 A and 60 mm semi-rigid cable between F840 A and Sampling Module.
The Amplifier was measured with 10 dB Attenuators between the outputs and the Sampling Module.
Gain and Bandwidth of the amplifier was set to maximum.
The measurement at 60 Gbps will be part of the inspection report delivered with each particular device.

Input Signal @ 100 Gbps,
Amplitude: 435 mV

Output Signal @ 100 Gbps,Amplitude: 1.40 V

Input Signal @ 80 Gbps,
Amplitude: 479 mV

Output Signal @ 80 Gbps,
Amplitude: 1.60 V

Input Signal @ 60 Gbps,
Amplitude: 492 mV

Output Signal @ 60 Gbps,
Amplitude: 1.84 V

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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Typical Differential Binary Waveforms (High Voltage Drive)
The measurements below had been performed using a SHF 12104 A Bit Pattern Generator(PRBS 231-1), a SHF 604 A POWER-MUX and a Tektronix DSA 8300 Digital Serial Analyzer (DSA) withPhase Reference Module (82A04B-60G), 70 GHz Sampling Module (80E11), 60 mm semi-rigid cablebetween SHF 616 A and F840 A and 60 mm semi-rigid cable between F840 A and Sampling Module.
The Amplifier was measured with 10 dB Attenuators between the outputs and the Sampling Module.
Gain and Bandwidth of the amplifier was set to maximum.

Input Signal @ 60 Gbps,Amplitude: 1.19 V

Output Signal @ 60 Gbps,Amplitude: 4.09 V

Input Signal @ 20 Gbps,
Amplitude: 1.27 V

Output Signal @ 20 Gbps,
Amplitude: 4.42 V

Input Signal @ 10 Gbps,Amplitude: 1.26 V

Output Signal @ 10 Gbps,
Amplitude: 4.48 V

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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Mechanical Drawing with Heat Sink
38
16.3

7.4

nc

nc

16.3

I2C

2020+9V
0.5A

7.43030

SHF F840 A
51035

InPOutN+11dBInN

OutP-70kHz - 55GHz

125128.5

126.2

SHF

Communication
Technologies AGGermany

26.2
20.3
15.2

x

72
M2x

10.1

11.8

16.3

16.9

20.3

m
5m
M2x419x

105

20m
4m

Pin assignment might change if a bias tee option is chosen.
Thermal resistance of heat sink approx. 4 K/WFor permanent mounting remove the heat sink from the amplifier. In that case please ensure thatadequate cooling of the amplifier is guaranteed. It is recommended to use thermal paste or a thermalgap pad for the mounting. In order to separate the heat sink from the amplifier, remove the four screws
on the heat sink. Please note, thermal paste is used between the heat sink and the amplifier housing.

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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Mechanical Drawing with Heat Sink Option DHS

21.5

31.5

55

Dual Heat Sink, two amplifiers on one heatsink

7.6

7.6
25
75.7
92.8
145
170

6.1

31.4

37.5

4x Ø5.7

8.8
161.2

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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2x M2 x5mm

6.3

14.1

Mechanical Drawing without Heat Sink

2262812.4

ncnc

I2C

SHF F840 A

13510353744

41.7+9V
0.5A

12.4

InP+

InN

-OutN

2

SHF

4

Communication
Technologies AG
Germany

6.3

10.5

OutP

70kHz - 55GHz

20.5

20.5

10.5

11dB

6.6
21.2
15.3
10.2
2x

1.9

5

6.3

6.9mmx5

10.3

2M

5.1
26 7 8 925.8

Non-Inverting Input (InP)

2.2

Inverting Input (InN)

Non-Inverting Output (OutP)
GND2MInverting Output (OutN)

4567894x3812Connector

29Portxm5m+9 V / 0.5 A
nc / Opt. Bias Tee OutP
nc / Opt. Bias Tee OutN
2IC

all dimensions in mm

Pin assignment might change if a bias tee option is chosen.
Please ensure that adequate cooling of the amplifier is guaranteed.

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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User Instructions
ATTENTION!
Electrostatic sensitive InP amplifier1.

To prevent damage through static charge build up, cables should be always discharged before
connecting them to the amplifier!

2.

Attach a 50 Ohm output load on each of the two outputs before supplying DC power to the amplifier!

3.

The supply voltage can be taken from any regular 8…12 V, (0.5 A @ 9V) DC power supply and canbe connected to the supply feed-through filter via an ON / OFF switch.
In case 9 V are applied to the amplifier typically 0.5 A are drawn during operation. However, theamplifier requires more current during start up. This is particularly important in case the current
compliance of a very fast acting voltage source is set too tight. As this can prevent the amplifier fromstarting properly, please allow up to 100% overhead for your current compliance during startup.

4.

Using a 3 dB or 6 dB input attenuator will result in a 6 dB or 12 dB increase of the input return loss.
For minimal degradation of amplifier rise time, these attenuators should have a bandwidth
specification of greater 50 GHz (V/ 1.85mm attenuators)!

5.

A differential input signal of about 1.2 Vpp will produce differential output swing of about 4 Vpp.
Higher input voltages are leading to waveform degradation.

6.

The amplifier can only be used without damage by connecting two 50 Ohm loads to the outputs.

7.

ATTENTION: At radio frequencies a capacitive load can be transformed to an inductive one throughtransmission lines! With an output stage driven into saturation this may lead to the immediate
destruction of the amplifier (within a few ps)!

8.

The (single ended) input voltages should never be greater than 1 Vpp equivalent to 4 dBm input
power for each input port, without power supply or 0.7 Vpp resp. 0 dBm in operation.

9.

For the DC-connections flexible cable 0.2…0.5 mm2 / AWG 24…20 are recommended. A maximum
soldering temperature of 260 °C for 3 seconds is recommended for the feedthrough (positive supply
voltage and bias tees pin). The ground pin requires significantly more heat as it is connected to thesolid housing.

SHF reserves the right to change specifications and design without notice - SHF F840 A - V003 - July 21, 2020

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