Datasheet

MAX4822–MAX4825
+3.3V/+5V, 8-Channel Relay Drivers with Fast
Recovery Time and Power-Save Mode
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MAX4822/MAX4823 Pin Description
PIN
MAX4822
MAX4823
NAME FUNCTION
11RESET
Reset Input. Drive RESET low to clear all latches and registers (all outputs are high
impedance). RESET overrides all other inputs. If RESET and SET are pulled low at the
same time, then RESET takes precedence.
22CS
Chip-Select Input. Drive CS low to select the device. When CS is low, data at DIN is
clocked into the shift register on SCLK’s rising edge. Drive CS from low to high to latch
the data to the registers and activate the relay outputs.
33DIN Serial Data Input
44SCLK Serial Clock Input
55DOUT
Serial Data Output. DOUT is the output of the shift register. DOUT can be used to daisy-
chain multiple MAX4822/MAX4823 devices. The data at DOUT appears synchronous to
SCLK’s falling edge.
6 6, 13 N.C. No Connection. Not internally connected.
77GND Ground
88OUT8
Open-Drain Output 8. Connect OUT8 to the low side of a relay coil. This output is pulled
to PGND when activated, but otherwise is high impedance.
99OUT7
Open-Drain Output 7. Connect OUT7 to the low side of a relay coil. This output is pulled
to PGND when activated, but otherwise is high impedance.
10, 16 10, 16 PGND
Power Ground. PGND is a return for the output sinks. Connect PGND pins together and
to GND.
11 11 OUT6
Open-Drain Output 6. Connect OUT6 to the low side of a relay coil. This output is pulled
to PGND when activated, but otherwise is high impedance.
12 12 OUT5
Open-Drain Output 5. Connect OUT5 to the low side of a relay coil. This output is pulled
to PGND when activated, but otherwise is high impedance.
13 — PSAVE
Power-Save Control. Connect a timing capacitor from PSAVE to ground. The capacitor
value determines power-save timing as explained under the Applications Information
section. PSAVE can also be driven externally to control power-save mode
asynchronously. When asserted high, PSAVE reduces the current to all active outputs as
determined by the Power-Save Configuration Register (see Figure 1). To disable power-
save mode in all channels, drive PSAVE low for at least 3ms after the last output setting.
14 14 OUT4
Open-Drain Output 4. Connect OUT4 to the low side of a relay coil. This output is pulled
to PGND when activated, but otherwise is high impedance.
15 15 OUT3
Open-Drain Output 3. Connect OUT3 to the low side of a relay coil. This output is pulled
to PGND when activated, but otherwise is high impedance.
17 17 OUT2
Open-Drain Output 2. Connect OUT2 to the low side of a relay coil. This output is pulled
to PGND when activated, but otherwise is high impedance.
18 18 OUT1
Open-Drain Output 1. Connect OUT1 to the low side of a relay coil. This output is pulled
to PGND when activated, but otherwise is high impedance.