MAX382/MAX384
Low-Voltage, 8-Channel/Dual 4-Channel
Multiplexers with Latchable Inputs
_______________________________________________________________________________________ 7
______________________________________________________________Pin Description
2, 17
PIN
MAX382 MAX384
NAME* FUNCTION
1 WR WRITE Logic Input
—
1
A0, A1 Address Logic Inputs (see
Truth Tables
at end of data sheet)
3 3 EN Enable Logic Input (see
Truth Tables
at end of data sheet)
4 4 V- Negative Supply Voltage Input. Connect to GND for single-supply operation.
5–8 — NO1–NO4 Analog Signal Inputs—bidirectional
— 5–8 NO1A–NO4A Analog Signal Inputs—bidirectional
9 — COM Analog Signal Output—bidirectional
— 9, 10 COMA, COMB Analog Signal Outputs—bidirectional
10–13 — NO8–NO5 Analog Signal Inputs—bidirectional
— 11–14 NO4B–NO1B Analog Signal Inputs—bidirectional
14 15 V+ Positive Supply Voltage Input
15 16 GND Ground
2, 16, 17 A0, A2, A1 Address Logic Inputs (see
Truth Tables
at end of data sheet)—
18 18 RS RESET Logic Input
__________Applications Information
The internal structures of the MAX382/MAX384 include
translators for the A2/A1/EN/WR/RS digital inputs, latch-
es, and a decode section for channel selection (see
Truth Tables
). The analog-signal switches consist of
parallel combinations of N and P MOSFETs.
WRITE (WR) and RESET (RS) strobes are provided for
interfacing with µP-bus lines, alleviating the need for the
µP to provide constant address inputs to the mux to
hold a particular channel (Figures 2–7).
When the WR strobe is in the low state (less than 0.8V)
and the RS strobe is in the high state (greater than
2.4V), the muxes are in the transparent mode—they
act similar to nonlatching devices, such as the
MAX398/MAX399.
When the WR goes high, the previous BCD address
input is latched and held in that state indefinitely.
RS turns off all channels when it is low. All switches stay
off until RS and EN are high and WR is low.
The MAX382/MAX384 work with both single and dual
supplies and function over the +2.4V to +16V single-
supply range. For example, with a single +5V power
supply, analog signals in the 0V to +5V range can be
switched normally. If negative signals around 0V are
expected, a negative supply is needed.
The EN latch allows all switches to be turned off under
program control. This is useful when two or more are
cascaded to build 16-line and larger analog-signal mul-
tiplexers.
*Analog inputs and outputs are names of convenience only. Inputs and outputs are identical and interchangeable.
