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General 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. The state of each switch is sampled

through an SPI™ interface by reading the status register

and any switch can be prohibited from asserting an inter-

rupt by writing to the command register. Four of the

switch inputs are intended for ground-connected switch-

es (IN0–IN3), and the other four inputs (IN4–IN7), are

programmable in groups of two for either ground-con-

nected or battery-connected switches. Two switch inputs

(IN0, IN1) have direct level-shifted outputs (DO0, DO1)

to be used for PWM or other timing-based signals.

Switch input thresholds are set to 50% of the voltage

applied to BATREF. The threshold hysteresis is set by

connecting an external resistor from HYST to ground.

The MAX13036 supplies an adjustable wetting current to

each closed switch to clean mechanical switch contacts

that are exposed to adverse conditions.

The MAX13036 operates with a +6V to +26V battery volt-

age applied to BAT. A separate +2.7V to +5.5V logic sup-

ply input (V

) sets the interface voltage. The MAX13036 is

available in a 5mm x 5mm 28-pin TQFN package and

operates over the -40°C to +125°C temperature range.

Applications

Features

o +6V to +26V Operating Voltage Range

o +42V Compatibility on BAT

o Inputs Withstand Reverse Battery

o Withstands Dynamic Battery Voltage Drop While

is Present

o Ultra-Low Operating Current 17µA (typ) in

Scan Mode

o Resistor-Adjustable Switching Hysteresis

o CMOS-Compatible Logic Outputs (+2.7V min)

o Built-In Switch Debouncing

o Interrupt Output

o Immunity to Transients

o High Modularity

o Thermal Protection

o ±8kV HBM ESD Protection on IN0–IN7 Without

External Components

o Two Inputs (IN0, IN1) Programmable as Direct

Outputs

o Four Inputs (IN4–IN7) Programmable for BAT or

GND Related Switches

MAX13036

Automotive Contact Monitor

and Level Shifter

________________________________________________________________

Maxim Integrated Products

MAX13036

TQFN

TOP VIEW

DO0

GND

BATREF

BAT

N.C.

INO

DO1

N.C.

CLK

SDI

SDO

INT

GND

TDEB

WET

HYST

N.C.

*EP

*CONNECT EXPOSED PADDLE TO GROUND

IN7

IN6

IN5

IN4

IN3

IN2

IN1

Pin Configuration

19-0808; Rev 0; 4/07

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

EVALUATION KIT

AVAILABLE

Ordering Information

Denotes lead-free package.

EP = Exposed paddle.

PART TEMP RANGE

PIN-

PACKAGE

PKG

CODE

MAX13036ATI+ -40°C to +125°C

28 TQFN-EP*

(5mm x 5mm)

T2855-8

Body Computers

Window Lifters

Seat Movers

Electric Sunroofs

Other Control ECUs

Typical Application Circuit appears at end of data sheet.

SPI is a trademark of Motorola, Inc.

Summary of content (18 pages)

PAGE 1
9-0808; Rev 0; 4/07 KIT ATION EVALU E L B AVAILA Automotive Contact Monitor and Level Shifter 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. The state of each switch is sampled through an SPI™ interface by reading the status register and any switch can be prohibited from asserting an interrupt by writing to the command register.
PAGE 2
MAX13036 Automotive Contact Monitor and Level Shifter ABSOLUTE MAXIMUM RATINGS (All voltages referenced to GND, unless otherwise noted.) VL ...........................................................................-0.3V to +6.0V BAT.........................................................................-0.3V to +42V BATREF, IN_ to BAT ................................................-45V to +45V BATREF, IN_ to GND...............................................-45V to +45V SD...............................
PAGE 3
Automotive Contact Monitor and Level Shifter (VL = +2.7V to +5.5V, BAT = +6V to +26V, SD = VL, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VL = +3.
PAGE 4
MAX13036 Automotive Contact Monitor and Level Shifter TIMING CHARACTERISTICS (VL = +2.7V to +5.5V, BAT = +6V to +26V, SD = VL, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VL = +3.3V, BAT = +14V, TA = +25°C) (Note 1) PARAMETER IN0 to DO0 Propagation Delay IN1 to DO1 Propagation Delay SYMBOL tPROP TYP MAX VBAT = 6V CONDITIONS MIN 22 35 VBAT = +14V 22 UNITS µs CLK Frequency fCLK Input rise/fall time < 2ns, VL = +3.0V to +5.
PAGE 5
Automotive Contact Monitor and Level Shifter CS tLEAD tLAG CLK tSI(SU) SDI tSI(HOLD) MSB IN tSO(EN) SDO tSO(DIS) tVALID MSB OUT LSB OUT Figure 1. SPI Timing Characteristics VL CS 1kΩ tSO(EN) MAX13036 CS tSO(DIS) SDO 15pF SDO 1/3VL VOL + 0.1VL Figure 2.
PAGE 6
Typical Operating Characteristics (VL = +3.3V, BAT = +14V, SD = VL, RWET = 61kΩ, RHYST = 90kΩ, CTDEB = 4700pF, TA = +25°C, unless otherwise noted.) WETTING CURRENT (mA) 20 GND-CONNECTED SWITCH 0 BAT-CONNECTED SWITCH -10 -20 -30 10 14 18 VBAT (V) 22 ADJUSTABLE HYSTERESIS ON MAX13036 toc02 BAT-CONNECTED SWITCH 30 80 130 180 230 RWET (kΩ) 280 20ms/div 330 BAT CURRENT vs. TEMPERATURE (SHUTDOWN MODE) 5 MAX13036 toc04 80 IIN_ 20mA/div -30 -40 -50 -60 BAT CURRENT vs.
PAGE 7
Automotive Contact Monitor and Level Shifter SWITCHING THRESHOLD vs. TEMPERATURE 9 8 VIN_ RISING 7 VIN_ FALLING 6 MAX13036 toc11 SWITCHING THRESHOLD (V) ADJUSTABLE HYSTERESIS OFF SWITCHING THRESHOLD vs.
PAGE 8
Automotive Contact Monitor and Level Shifter MAX13036 Pin Description 8 PIN NAME FUNCTION 1 IN1 Switch Input Channel 1. Connect IN1 to a switch connected to GND. IN1 can be programmed as a direct input with a level-shifted output on DO1 (see the Mechanical Switch Inputs (IN0–IN7) section). 2 IN2 Switch Input Channel 2. Connect IN2 to a switch connected to GND. 3 IN3 Switch Input Channel 3. Connect IN3 to a switch connected to GND. 4 IN4 Switch Input Channel 4.
PAGE 9
Automotive Contact Monitor and Level Shifter SD BAT VL DO0 MAX13036 DO1 BATREF DIGITAL INTERFACE IN0 CS SPI INTERFACE IN1 IN3 IN4 CLK SDI IN2 WETTING CURRENT CONTROL LEVEL TRANSLATORS SDO SHIFT REGISTER INT IN5 INTERRUPT LOGIC IN6 OT IN7 WET HYST TDEB 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.
PAGE 10
MAX13036 Automotive Contact Monitor and Level Shifter The first four inputs (IN0–IN3) are intended for groundconnected switches. The remaining four inputs (IN4–IN7) can be programmed in sets of two for either ground-connected or battery-connected switches by writing to the M0 and M1 bits (see Table 5). The default state after power-up is IN2–IN7 configured for ground-connected switches, and IN0/IN1 configured for direct inputs.
PAGE 11
Automotive Contact Monitor and Level Shifter Wetting current is activated on closed switches just after the debounce time. The wetting current pulse starts after the debounce time. A wetting current pulse is provided to all closed switches when a valid input change is detected. Wetting current rise and fall times are controlled to enhance EMC performance. There is one wetting current timer for all switch inputs.
PAGE 12
MAX13036 Automotive Contact Monitor and Level Shifter STATUS REGISTER IS COPIED TO SHIFT REGISTER SHIFT REGISTER IS COPIED TO COMMAND REGISTER CS 15 CLK SDI 14 WTOFF SC2 SW7 SDO 13 12 SC1 SC0 SW6 SW5 11 10 WEN WEND SW4 SW3 SW2 9 8 7 6 5 4 3 2 1 0 M1 M0 P7 P6 P5 P4 P3 P2 P1 P0 SW1 SW0 OT * * * * * * * * = UNUSED. Figure 5.
PAGE 13
Automotive Contact Monitor and Level Shifter Table 3. Programmable Scanning Period SC2 SC1 SC0 SCANNING PERIOD (ms) 0 0 0 64 0 0 1 32 0 1 0 16 0 1 1 8 1 0 0 4 1 0 1 2 ning period ([SC2:SC1:SC0] = [1:1:1] or [1:1:0]), the switch inputs are constantly being monitored and the sense resistors are always connected. The state [SC2:SC1:SC0] = [1:1:0] also disables adjustable hysteresis (normally set by RHYST) and fixes hysteresis at 0.166 x VBATREF.
PAGE 14
MAX13036 Automotive Contact Monitor and Level Shifter Table 5. Switch Configuration Controlled by M1 and M0 M0 IN7 AND IN6 SWITCH CONFIGURATION IN5 AND IN4 SWITCH CONFIGURATION IN3–IN0 SWITCH CONFIGURATION 0 0 Ground Ground Ground 0 1 Ground Battery Ground 1 0 Battery Ground Ground 1 1 Battery Battery Ground M1 Table 4). The DO0 and DO1 outputs are tri-stated when WEND = 1.
PAGE 15
Automotive Contact Monitor and Level Shifter Human Body Model The MAX13036 IN7–IN0 pins are characterized for ±8kV ESD protection using the Human Body Model. Figure 7a shows the Human Body Model and Figure 7b shows the current waveform it generates when discharged into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the device through a 1.5kΩ resistor.
PAGE 16
Automotive Contact Monitor and Level Shifter MAX13036 Typical Application Circuit BATTERY +6V TO +26V, +42V LOAD DUMP ECU CONNECTOR 0.01μF 4700pF IN0 IN1 IN2 IN3 IN4 IN5 IN6 IN7 BATREF TDEB BAT 47μF WET 0.1μF MAX13036 HYST 61kΩ 90kΩ IN +3.3V REGULATOR OUT GND DO0 VL DO1 SD SDO SDI CLK CS INT OT 0.
PAGE 17
Automotive Contact Monitor and Level Shifter QFN THIN.EPS PACKAGE OUTLINE, 16, 20, 28, 32, 40L THIN QFN, 5x5x0.8mm 21-0140 K 1 2 ______________________________________________________________________________________ 17 MAX13036 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.
PAGE 18
MAX13036 Automotive Contact Monitor and Level Shifter Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) PACKAGE OUTLINE, 16, 20, 28, 32, 40L THIN QFN, 5x5x0.8mm 21-0140 K 2 2 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.