SHF Communication Technologies AGWilhelm-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 D837 C
Differential to Single-Ended
Linear Broadband Amplifier

SHF reserves the right to change specifications and design without notice - SHF D837 C - V002 - Aug 25, 2023

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Description
The SHF D837 C is a RoHS compliant differential input, single-ended output linear amplifier designed
for PAM4 and 16QAM applications. The single-ended output drive amplitude of up to at least 3 V linear
is particularly well suited for state-of-the-art single-drive DP-16QAM modulators. When driven from thedifferential outputs of a high performance DAC, the common-mode rejection characteristic of thisdifferential input design helps to maintain the linearity and resolution of the DAC.
This amplifier is of a single chip design based on state-of-the-art commercial GaAs process, housed in a
special low loss carrier PCB environment to maintain wide bandwidth and low group delay variation,necessary for high performance operation.
Like other amplifiers in the product family, this amplifier enjoys the same benefit of an internal voltage
regulation to protect against accidental reverse voltage connection. Similarly, the output amplitude andcrossing adjustment using software control via an USB connection. Once adjusted, the connection canbe removed until the next time.

Ease of Use
Upon delivery, the amplifier is already pre-set to deliver maximum gain, maximum output amplitude andnominally 50% crossing.
These settings 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, as well as the required
software are included with each amplifier with 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, maximum
amplitude or crossing adjustments are to be made.
The software is available for download at www.shf-communication.com/software .

GUI of the SHF amplifier control software V1.7

Available Options
03: DC return on output (max. ±1.75 V, max. 35 mA)

1

04: Built-in bias tee on output (max. ±7 V, max. 220 mA)

11

The options 03 & 04 cannot be combined.
If an option is chosen, the maximum gain and the maximum output power might be reduced by up to 1 dB. The low frequency
3 dB Point might be increased up to 80 kHz. The DC resistance of an bias tee is about 3 Ω.

SHF reserves the right to change specifications and design without notice - SHF D837 C - V002 - Aug 25, 2023

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Specifications – SHF D837 CParameterUnitSymbolMin

TypMaxConditions

Maximum RF Input Powerin OperationdBm
VPin max

41single ended

Maximum RF Input Power
without Power SupplydBm
VPin max

102single ended

DC Voltage at RF Input

V±9AC coupled input

DC Voltage at RF Output

V±7

AC coupled output

Supply Voltage

V

120.4 A, reverse voltage protected

Absolute Maximum Ratings

Case Temperature

2Tcase8°C

1040

peak to peak voltage

peak to peak voltage

50

Electrical Characteristics (At 40°C case temperature, unless otherwise specified)
GHzfHIGH InP

45single ended 3, non-inverting input

GHzfHIGH InN

32single ended 3, inverting input

GHzfHIGH Diff

35

Calculated from single ended

Low Frequency 3 dB Point

kHzfLOWGain

dBS21

Gain Ripple

dBΔS21Max. Gain ReductiondB

Output Power at 1 dB
Compression

dBm
V

Output Power at 2 dB
Compression
Output Power at 3 dB
Compression

High Frequency 3 dB Point50
910each inputs
measured at Pin= -30 dBm±0.5±140 MHz…25 GHz, relative to gain-slope-2.5-3-4Control via software interface

P01dB

122.5

132.810 MHz…25 GHzdBm
VP02dB

15
3.6

16
4.0

10 MHz…25 GHzdBm
VP03dB

164.0

174.5

10 MHz…25 GHz

3 Order Intercept PointdBm

IP325Max. RF Input for LinearOperationdBm
VPin linrdpeak to peak voltage

peak to peak voltage

peak to peak voltage

-3
0.45

I.e. Pout ≤ P01dB
peak to peak voltage, single ended
Pin ≥ - 2 dBm

Max. Output PowerReductiondB

Crossing might need to be readjusted
by using the crossing control feature.

tbdControl via software interface

Crossing ControlRange%-44Control via software interface
Vout ~2.5 V

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

3Single ended measurement condition with -30 dBm input power

SHF reserves the right to change specifications and design without notice - SHF D837 C - V002 - Aug 25, 2023

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Parameter

UnitSymbolMinTypMax

Conditions

Input Reflection

dBS11-12-9< 10 GHz, single ended

Output Reflection

dBS22-9< 30 GHz< 30 GHz, single ended

20%...80%, 2.5 V ≤ Vout ≤ 3.5 V

Rise Time/Fall Time

pstr/tf711

Deconvoluted 4, 5
Full Setup 4
2.5 V ≤ Vout ≤ 3.5 VJitterfs

Group Delay Ripple

psPower Consumption

WJRMS

500580550650Deconvoluted 4, 5±5040 MHz…30 GHz, 100 MHz aperture

2.7

Full Setup 4

9 V supply voltage

Mechanical Characteristics
Input Connectors

1.85 mm (V) female 6

Output Connector

1.85 mm (V) male 6

4

Measured with: SHF 613 A DAC -> DUT (SHF D837 C) -> Agilent 86100C with 70 GHz sampling head & precision time base.

5Calculation based on typical results of setup without DUT :𝑡𝑟 /𝑡𝑓 𝑑𝑒𝑐𝑜𝑛𝑣𝑜𝑙𝑢𝑡𝑒𝑑 = √(𝑡𝑟 /𝑡𝑓 𝑓𝑢𝑙𝑙 𝑠𝑒𝑡𝑢𝑝 )2 − (𝑡𝑟 /𝑡𝑓 𝑠𝑒𝑡𝑢𝑝 𝑤/𝑜 𝐷𝑈𝑇 )2 = √(𝑡𝑟 /𝑡𝑓 𝑓𝑢𝑙𝑙 𝑠𝑒𝑡𝑢𝑝 )2 − 11 𝑝𝑠 2
2𝐽𝑅𝑀𝑆 𝑑𝑒𝑐𝑜𝑛𝑣𝑜𝑙𝑢𝑡𝑒𝑑 = √(𝐽𝑅𝑀𝑆 𝑓𝑢𝑙𝑙 𝑠𝑒𝑡𝑢𝑝 )2 − (𝐽𝑅𝑀𝑆 𝑠𝑒𝑡𝑢𝑝 𝑤/𝑜 𝐷𝑈𝑇 ) = √(𝐽𝑅𝑀𝑆 𝑓𝑢𝑙𝑙 𝑠𝑒𝑡𝑢𝑝 )2 − 360 𝑓𝑠 2
6

Other gender configurations are available on request. Other connector types are also available but may impact bandwidth &reflection.
SHF reserves the right to change specifications and design without notice - SHF D837 C - V002 - Aug 25, 2023

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Typical S-Parameters, Group Delay and Phase Response
Single-Ended Measurements
00

SE_Reverse_Isolation_InN_dB
SE_Reverse_Isolation_InP_dB

Input_Reflection_InN_dB
Input_Reflection_InP_dB-5-10-15-20-25-30-35-40-45-50-10-20-30-40-50-60-70-80-900510 15 20 25 30 35 40 45 50 55 60 65

0510 15 20 25 30 35 40 45 50 55 60 65

Frequency [GHz]Frequency [GHz]300-5

Output_Reflection_dB

SE_Gain_InN_dB
SE_Gain_InP_dB252015105-10-15-20-25-30-35-40-450-500510 15 20 25 30 35 40 45 50 55 60 650510 15 20 25 30 35 40 45 50 55 60 65

Frequency [GHz]Frequency [GHz]250200200150100100

SE_GD_InN_ps
SE_GD_InP_ps

SE_Phase_InN_deg
SE_Phase_InP_deg

150500-50-100500-50-100-150-150-200-250-200
010203040Frequency [GHz]5060 650102030405060 65

Frequency [GHz]SHF reserves the right to change specifications and design without notice - SHF D837 C - V002 - Aug 25, 2023

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Typical Frequency Response
Differential to Single-Ended (calculated from Single-Ended Measurements)

Typical Common-Mode-Rejection-Ratio (CMRR)SHF reserves the right to change specifications and design without notice - SHF D837 C - V002 - Aug 25, 2023

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Typical Binary Eye Diagrams
The measurements below had been performed using a SHF 613 A DAC and an Agilent 86100D DCAwith Precision Time Base Module (86107A) and 70 GHz Sampling Head (86118A).

Input Signal InP @ 45 Gbps,
Eye amplitude: 369 mV

Input Signal InN @ 45 Gbps,
Eye amplitude: 377 mV

Output Signal @ 45 Gbps,
Eye amplitude: 2.7 V

Input Signal InP @ 50 Gbps,Eye amplitude: 370 mV

Input Signal InN @ 50 Gbps,
Eye amplitude: 380 mV

Output Signal @ 50 Gbps,
Eye amplitude: 2.6 V

Input Signal InP @ 56 Gbps,
Eye amplitude: 365 mV

Input Signal InN @ 56 Gbps,
Eye amplitude: 377 mV

Output Signal @ 56 Gbps,
Eye amplitude: 2.4 V

SHF reserves the right to change specifications and design without notice - SHF D837 C - V002 - Aug 25, 2023

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Typical 4-Level Eye diagrams
The measurements below had been performed using a SHF 613 A DAC and an Agilent 86100D DCA
with Precision Time Base Module (86107A) and 70 GHz Sampling Head (86118A).

Input Signal InP @ 45 GBaud,Eye amplitude: 448 mV

Input Signal InN @ 45 GBaud,Eye amplitude: 448 mV

Output Signal @ 45 GBaud,Eye amplitude: 3.1 V

Input Signal InP @ 50 GBaud,Eye amplitude: 442 mV

Input Signal InN @ 50 GBaud,Eye amplitude: 450 mV

Output Signal @ 50 GBaud,Eye amplitude: 3.1 V

Input Signal InP @ 56 GBaud,Eye amplitude: 450 mV

Input Signal InN @ 56 GBaud,Eye amplitude: 450 mV

Output Signal @ 56 GBaud,Eye amplitude: 3.0 V

SHF reserves the right to change specifications and design without notice - SHF D837 C - V002 - Aug 25, 2023

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Typical Low Frequency Response (<1 MHz)

Typical Saturation Power Characteristic(single-ended measurement InN to Out)Top (red):
3 dB compression;
Middle (green): 2 dB compression;
Bottom (blue): 1 dB compression

SHF reserves the right to change specifications and design without notice - SHF D837 C - V002 - Aug 25, 2023

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Mechanical Drawing with Heat Sink
2x M4 x 5 mm

20105Connector

12

Non-Inverting Input

3Output

Inverting Input

456740

16.3

24.1

PortGND+9 V / 0.4 A
nc (BiasT)
nc4mm

3.7

1×29.7
10.2
10.7
7.6

10 dB-SHF+

58407

P03dB: 16 dBm

60 kHz - 35 GHzncnc
GND+9V0.4A

9.8

SHF D837 C

38I2C2xM
2

10.7

34

7
652

46

11.8
16.3
16.9
20.2

27.5
37.5

16.3

125

33.5

In standard configuration pin 6 is not connected (nc). If an output bias-tee (option 04) is included theDC bias can be connected to pin 6 (BiasT).
Thermal resistance of heat sink approx. 4 K/W
For permanent mounting remove the heat sink from the amplifier. In that case please ensure that
adequate cooling of the amplifier is guaranteed. It is recommended to use thermal paste or a thermal
gap 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 D837 C - V002 - Aug 25, 2023

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4x M2 x 5mm

Mechanical Drawing without Heat Sink

8.5
18.5Connector

12Non-Inverting Input

3Output

Inverting Input

4567

GND+9 V / 0.4 A
nc (BiasT)
nc

6.3

14.1

36

Port

10.1

7
28.2
10.2

35

10 dB

6542

45
50
522

6.1

1

11.3

9.2

-SHF+

58407

P03dB: 16 dBm

60 kHz - 35 GHz

SHF D837 Cncnc

2GND+9V0.4A

33I2C

12.2

32x M2 × 4mm

2x M2 x 4mm

49.7

1.9
6.3
6.9
6.3

10.3
12.5

In standard configuration pin 6 is not connected (nc). If an output bias-tee (option 04) is included theDC bias can be connected to pin 6 (BiasT).
Please ensure that adequate cooling of the amplifier is guaranteed.

SHF reserves the right to change specifications and design without notice - SHF D837 C - V002 - Aug 25, 2023

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User Instructions
ATTENTION!
Electrostatic sensitive GaAs FET 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 before supplying DC power to the amplifier!

3.

The supply voltage can be taken from any regular 8…12 V, 0.4 A DC power supply and can beconnected to the supply feed-through filter via an ON / OFF switch.
In case 9 V are applied to the amplifier typically 0.4 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 Vpp will produce output swing of about 3 Vpp. Higher input
voltages are leading to waveform degradation.

6.

The amplifier can only be used without damage by connecting a 50 Ohm precision load to the output.

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 input voltage (single ended) should never be greater than 2 Vpp equivalent to 10 dBm input
power.

9.

In case a bias tee is connected to the amplifier, please note that abrupt connection or disconnectionof the RF port of such bias tees may cause harmful transients. Therefore, it is always recommended
not to connect or disconnect bias tees under bias voltage. For example, ramp down the bias to 0 V
before lifting a waver prober.

10.

For the DC-connections flexible cable 0.2…0.5 mm / 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 tee pin). The ground pin requires significantly more heat as it is connected to thesolid housing.

2SHF reserves the right to change specifications and design without notice - SHF D837 C - V002 - Aug 25, 2023

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