Detailed Description

The MAX3864 transimpedance amplifier is designed for

the MAX3864 comprises a transimpedance amplifier, a

voltage amplifier, an output buffer, an output filter, and

a DC cancellation circuit.

Transimpedance Amplifier

The signal current at the input flows into the summing

node of a high-gain amplifier. Shunt feedback through

clamp the output voltage for large input currents

(Figure 2).

Voltage Amplifier

The voltage amplifier converts single-ended signals to

differential signals and introduces a voltage gain.

Output Buffer

The output buffer provides a back-terminated voltage

output. The buffer is designed to drive a 100

Ω differen-

tial load between OUT+ and OUT-. The output voltage

is divided between internal 50

Ω load resistors and the

external load resistor. In the typical operating circuit,

this creates a voltage-divider with a ratio of 1/2. The

MAX3864 can also be terminated with higher output

impedances, which increases gain and output voltage

swings.

2.5Gbps, +3V to +5.5V, Wide Dynamic Range

Transimpedance Preamplifier

4

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Typical Operating Characteristics (continued)

Pin Description

200

100

0

-100

-200

-100

0

-50

50

100

DC TRANSFER FUNCTION

INPUT CURRENT (

µA)

EYE DIAGRAM (INPUT = 20

µAp-p)

80ps/div

PIN

NAME

FUNCTION

Supply Voltage

2

N.C.

No Connection

3

IN

Amplifier Input

4

FILTER

Provides bias voltage for the photodiode through a 750

disables the DC cancellation amplifier to allow a DC path from IN to OUT+ and OUT- for testing.

5

GND

Ground

6

OUT-

7

OUT+

8

GND

Ground

EYE DIAGRAM (INPUT = 2mAp-p)

80ps/div