ADA4530-1R-EBZ User Guide

UG-865

Rev. 0 | Page 9 of 14

TRANSIMPEDANCE WITH DIRECT SENSOR

CONNECTION

The ADA4530-1R-EBZ-TIA board can be reconfigured to allow

direct sensor connection. The P6 and P1, P2, or P3 pins are

provided to allow assembly of a photodiode. To reconfigure the

board, remove the input BNC connector (J1). The user must then

access Pin P6 (the inner conductor pin of the BNC connector).

Assemble the photodiode of choice between P6 and P1, P2, or P3.

P1, P2, and P3 are electrically connected to signal ground.

These three pins are provided to allow different photodiode

packages to be used, for example: TO-19, TO-5, or TO-8.

Table 8. Transimpedance with Direct Sensor Connection

Pad/Connector

Description

CF1

J1

Remove J1

JP2

0 Ω

JP3

Unconnected

RS1

0 Ω

Use pre-assembled 10 GΩ resistor or

replace with SMT resistor of choice

Used with through hole feedback resistor

to select CF1

PHOTODIODE

RS1

0Ω

RF2

CF1

JP2

Figure 17. Transimpedance with Direct Sensor Connection

U1

RO

499Ω

RF1 (SMT)

RF2 (THROUGH HOLE)

CF1

JP2

0Ω

PHOTODIODE

RS1

0Ω

V+

V–

J2

(BNC)

OUTPUT

Figure 18. Transimpedance with Direct Sensor Connection Schematic

INVERTING GAIN

To configure the ADA4530-1 in an inverting gain, use the

components shown in Table 9. Choose appropriate RF1 and JP2

values for the desired gain.

Pad

Description

JP2

Populate with resistor of choice

RS1

0 Ω

RF1

Replace 10 GΩ with resistor of choice

RF1

RS1

0Ω

JP2

Figure 19. Inverting Gain

J1

(BNC)

INPUT

J2

(BNC)

OUTPUT

U1

V+

RO

499Ω

RF1

V–

JP2

RS1

0Ω

Figure 20. Inverting Gain Schematic