AD8232

Data Sheet

Rev. A | Page 6 of 28

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

Figure 2. Pin Configuration

Table 3. Pin Function Descriptions

Pin No.

Mnemonic

Description

1

HPDRIVE

High-Pass Driver Output. Connect HPDRIVE to the capacitor in the first high-pass filter. The AD8232 drives this pin

to keep HPSENSE at the same level as the reference voltage.

2

+IN

Instrumentation Amplifier Positive Input. +IN is typically connected to the left arm (LA) electrode.

3

−IN

Instrumentation Amplifier Negative Input. −IN is typically connected to the right arm (RA) electrode.

4

RLDFB

Right Leg Drive Feedback Input. RLDFB is the feedback terminal for the right leg drive circuit.

5

RLD

Right Leg Drive Output. Connect the driven electrode (typically, right leg) to the RLD pin.

6

SW

Fast Restore Switch Terminal. Connect this terminal to the output of the second high-pass filter.

7

OPAMP+

Operational Amplifier Noninverting Input.

8

REFOUT

Reference Buffer Output. The instrumentation amplifier output is referenced to this potential. Use REFOUT as a

virtual ground for any point in the circuit that needs a signal reference.

9

OPAMP−

Operational Amplifier Inverting Input.

10

OUT

Operational Amplifier Output. The fully conditioned heart rate signal is present at this output. OUT can be

connected to the input of an ADC.

11

LOD−

Leads Off Comparator Output. In dc leads off detection mode, LOD− is high when the electrode to −IN is

disconnected, and it is low when connected. In ac leads off detection mode, LOD− is always low.

12

LOD+

Leads Off Comparator Output. In dc leads off detection mode, LOD+ is high when the +IN electrode is

disconnected, and it is low when connected. In ac leads off detection mode, LOD+ is high when either the −IN

or +IN electrode is disconnected, and it is low when both electrodes are connected.

13

SDN

Shutdown Control Input. Drive SDN low to enter the low power shutdown mode.

14

AC/DC

Leads Off Mode Control Input. Drive the AC/DC pin low for dc leads off mode. Drive the AC/DC pin high for ac leads

off mode.

15

FR

Fast Restore Control Input. Drive FR high to enable fast recovery mode; otherwise, drive it low.

16

GND

Power Supply Ground.

17

Power Supply Terminal.

18

REFIN

Reference Buffer Input. Use REFIN, a high impedance input terminal, to set the level of the reference buffer.

19

IAOUT

Instrumentation Amplifier Output Terminal.

20

HPSENSE

High-Pass Sense Input for Instrumentation Amplifier. Connect HPSENSE to the junction of R and C that sets the

corner frequency of the dc blocking circuit.

EP

Exposed Pad. Connect the exposed pad to GND or leave it unconnected.

14

13

12

1

3

4

AC/DC

15 FR

SDN

LOD+

11 LOD–

HPDRIVE

–IN

2

+IN

RLDFB

5

RLD

AD8232

TOP VIEW

NOTES

1. CONNECT THE EXPOSED PAD TO GND OR

LEAVE UNCONNECTED.