MAX13036 Datasheet, PDF (9/18 Pages) Maxim Integrated Products – Automotive Contact Monitor and Level Shifter

BATREF
IN0
IN1
IN2
IN3
IN4
IN5
IN6
IN7
Automotive Contact Monitor
and Level Shifter
Functional Diagram
SD
BAT
V_L
MAX13036
WETTING
CURRENT
CONTROL
LEVEL
TRANSLATORS
DO0
DO1
DIGITAL
INTERFACE
CS
SPI
CLK
INTERFACE
SDI
SHIFT
SDO
REGISTER
INT
INTERRUPT
LOGIC
OT
WET
HYST TDEB
GND
Detailed Description
The MAX13036 automotive contact monitor and level
shifter monitors and debounces eight remote mechanical
switches and asserts an interrupt (INT) if a switch
changes state. Any of the switch inputs can be prohibited
from asserting an interrupt. The switch threshold levels
are set to 50% of the voltage applied to BATREF. All
switch inputs feature a common adjustable hysteresis,
debounce time and wetting current. Two switch inputs
(IN0, IN1) are programmable to have direct outputs (DO0,
DO1) useable for PWM or other timing based signals.
The MAX13036 features an SPI interface to monitor
individual switch inputs and to configure interrupt
masking, hysteresis and wetting current enable/disable,
switch configuration (battery connected or ground con-
nected), and scanning period.
The MAX13036 features three modes of operation: nor-
mal mode, scan mode, and shutdown mode. In normal
mode, the part is fully functional and sensing resistors
are connected to all switch inputs. In scan mode, the
sensing resistors are connected for a finite duration to
reduce power consumption. In shutdown mode, all
switch inputs are high impedance to further reduce
power consumption.
VL
V_L is the power-supply input for the digital input/output
buffers. The SPI interface (CS, CLK, SDI, SDO), and
digital outputs (DO0, DO1) are referenced to the volt-
age on V_L. Connect V_L to the system’s +2.7V to +5.5V
logic-level supply. Bypass V_L to ground with a 0.1µF
capacitor placed as close as possible to the device.
BAT
BAT is the main power-supply input. Bypass BAT to
ground with a 0.1µF ceramic capacitor placed as close
as possible to BAT. In addition, bypass BAT with a
10µF or greater capacitor. BAT can withstand DC volt-
ages up to +42V.
Mechanical Switch Inputs (IN0–IN7)
IN0 through IN7 are the inputs for remote mechanical
switches. The status of each switch input is indicated
by the SW0 through SW7 bits in the status register, and
each switch input can be programmed to not assert an
interrupt (INT) by writing to the P0 through P7 bits in the
command register. All switch inputs are configured to
assert an interrupt upon power-up.
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