HMC690 Datasheet, PDF (7/10 Pages) Hittite Microwave Corporation – 10 Gbps TRANSIMPEDANCE AMPLIFIER

5
v04.0709
HMC690
10 Gbps TRANSIMPEDANCE
AMPLIFIER
Pad Descriptions
Pad Number
Function
1, 6, 13
GND
Description
Ground connection for TIA.
2
TEST
Test Input. This pad is connected internally to IN thru 1kΩ.
No external connection required.
3
4
5, 7
8, 15
9
IN
FILTER
Vcc1
Vcc2
Lin_EN
TIA Input.
Provides bias voltage for photo diode (PD)
thru a 300Ω resistor for Vcc1.
Power Supply for input stage and PD.
Power supply for output buffers.
HMC690 has an extended linear range feature. With this
feature disabled (pin 9 floating), the HMC690 operates
linearly for inputs less than 300 μAp-p. For input currents
greater than 300 μAp-p, the HMC690 begins to operate
within a saturated region. For input currents greater than
1 mA-p-p, the output is fully saturated. Enabling (pin 9
connected to 3.3V) this feature increases linear range
of the device up to 350 μA increasing nominal supply
current from 92 mA to 98 mA
Interface Schematic
DC offset control. Voltage at this pad sets output DC
10
Off_adj
offset. When it is floating DC offset is at 0V.
11
OUTP
Non-inverted data output with 50Ω back termination.
12
OUTN
Inverted data output with 50Ω back termination.
Received signal strength indicator. This pin provides
a voltage proportional to the DC input current. This
14
RSSI
voltage should be monitored during assembly to
optimally align the PD in the optical environment.
5-8
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20 Alpha Road, Chelmsford, MA 01824 Phone: [phone] Fax: [phone]
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