ADL5304

Data Sheet

Rev. A | Page 6 of 32

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

24 INPS

23 INMS

22 VLOG

21 SCL1

20 SCL2

19 SCL3

18 ACOM

17 2VLT

1

2

3

4

5

6

7

8

NIC

VSM1

VSM2

INUM

IDEN

IREF

VSM3

VSM4

ADL5304

TOP VIEW

(Not to Scale)

NOTES

1. NIC = NO INTERNAL CONNECTION.

2. CONNECT THE EXPOSED PADDLE TO THE VSM1 TO

VSM4 PINS TO PROVIDE LOW LEAKAGE GUARD.

Figure 2. 32-Lead LFCSP Pin Configuration

Table 3. Pin Function Descriptions

Pin No.

Mnemonic

Description

1, 25

NIC

No Internal Connection.

2, 3, 7, 8

VSM1 to VSM4

Guard Pins for the INUM and IDEN Inputs. Connect these pins to the 1P5V, DCBI, and INPS pins for default

single-supply setup; connect to ground if INUM (photodiode bias) is desired to be at ground (must have −5 V

< VNEG < −2 V).

4

INUM

Numerator Current Input.

5

IDEN

Denominator Current Input. Connect to the IREF pin for most applications.

6

IREF

100 nA Trimmed Reference Current Output. Connect to the IDEN pin for most applications.

9

VDEN

Voltage Output of Denominator Log Amplifier. Connect this pin to the INDN pin and decouple with an

external 0.1 µF capacitor to ground.

10

INDN

Denominator Voltage Input to Temperature Compensation Circuit.

11

COMM

Main Ground.

12

NMFS

Numerator Speed Bias (Nominal 1 kΩ Resistor to VNEG Pin).

13

VNEG

Negative Supply.

14

DNFS

Denominator Speed Bias (Nominal 1 kΩ Resistor to VNEG Pin).

15, 18

ACOM

Analog Common, Low Noise Reference Ground. Important that both pins are always grounded.

16

HFCP

High Frequency Compensation.

17

2VLT

2.0 V Reference Output.

19

SCL3

7.5 kΩ Scaling Resistor (See Figure 1). Default is NIC.

20

SCL2

5 kΩ Scaling Resistor (See Figure 1). Default is to connect to the INMS pin.

21

SCL1

5 kΩ Scaling Resistor (See Figure 1). Default is to connect to the VLOG pin.

22

VLOG

23

INMS

Output Buffer Amplifier Inverting Input.

24

INPS

Output Buffer Amplifier Noninverting Input. The INPS, DCBI, and VSM1 to VSM4 pins must be tied together.

26

1P5V

1.5 V Reference Output. Connect to the INPS, DCBI, and VSM1 to VSM4 pins for single-supply operation.

27

DCBI

Approximately 1.3 mA Bias Current. Connect this pin to the VSM1 to VSM4 pins. See Pin 2, Pin 3, Pin 7, and Pin 8

description.

28

BSDC

Internal Bias Node. Decouple with a series connection of 4 Ω and 1 µF to ground.

29

VPOS

Positive Supply.

30

IMON

31

INNM

Numerator Voltage Input to Temperature Compensation Circuit.

32

VNUM

Voltage Output of Numerator Log Amplifier. Connect this pin to the INNM pin. For the fastest response, do

not add an external capacitor.

0

EPAD

Exposed paddle. Connect the exposed paddle to the VSM1 to VSM4 pins to provide low leakage guard.