1. HPDRIVE high pass driver output. The capacitor should be connected to the first high pass filter in HPDRIVE.
AD8232 driver this pin to keep the HPSENSE at the same level as the reference voltage.
2. +IN instrumentation amplifier positive input. +IN is usually connected to the left arm (LA) electrode.
3. – IN instrumentation amplifier negative input. – IN is usually connected to the right arm (RA) electrode.
4. RLDFB right leg driver feedback input. RLDFB is the right leg driver circuit feedback pin.
5. RLD right leg driver output. The drive electrodes (usually for the right leg) should be connected to the RLD pin.
6. SW fast recovery switch pin. This pin should be connected to the output of the second high pass filter.
7. OPAMP+ op amp inverting input.
8. REFOUT reference voltage buffer output. Instrument amplifier output reference this potential.
REFOUT should be used as a virtual ground for any point in a circuit that requires a reference signal.
9. OPAMP operational amplifier inverting input.
10. OUT op amp output. This output provides a fully conditioned heart rate signal.
OUT can be connected to the input side of the ADC.
11. LOD – lead off output end of the comparator. Fall detection mode in DC lead, and when the IN electrode is disconnected,
LOD – in the high state, otherwise it is in a low state. In the exchange of lead off detection mode, LOD is always in the low state.
Lead off comparator output. In the DC lead off detection mode, when the +IN electrode is disconnected, the LOD+ is in a high level,
On the contrary, it is in a low level state. In the exchange of lead off detection mode, and when the IN or +IN electrode is disconnected, LOD+ is in a high level state,
When these two electrodes are connected, they are in a low level state.
12. LOD+
13. SDN shutdown control input. Driving the SDN to a low level, which can be turned into a low power shutdown mode.
14. AC/DC lead off mode control input. For DC lead off mode, the AC/DC pin should be driven to a low level.
For the AC lead off mode, the AC/DC pin should be driven to the highest level.
15. FR fast recovery control input. FR drive to the high level can be fast recovery mode; otherwise, it should be driven to a low level.
16. GND power supply.
17. +VS supply pin.
18. REFIN reference voltage buffer input. REFIN (high impedance input pins) can be used to set the level of the reference voltage buffers.
19. IAOUT instrumentation amplifier output pin.
20. HPSENSE instrumentation amplifier for high pass detection input.
HPSENSE is connected to the R and C nodes that are set at the turn frequency of the DC blocking circuit.
EP exposed pad. The exposed pad should be GND or not connected