Datasheet

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 +V
S
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
7
OPAMP+
6
SW
8
REFOUT
9
OPAMP–
10
OUT
19
IAOUT
20
HPSENSE
18
REFIN
17
+V
S
16
GND
AD8232
TOP VIEW
NOTES
1. CONNECT THE EXPOSED PAD TO GND OR
LEAVE UNCONNECTED.
10866-002