19-4464; Rev 0; 2/09 KIT ATION EVALU E L B A AVAIL 24-Channel Automotive Switch Monitor The MAX13362 is a 24-channel automotive contact monitor designed as an interface between mechanical switches and low-voltage processors or other logic circuits. The IC operates over a voltage range of 5.5V to 28V, and withstands voltages up to 40V. It protects lowvoltage circuitry from high voltages and reverse battery conditions. The MAX13362’s low-current operation under all operating conditions makes it suitable for use in electronic control units (ECUs) that are connected directly to the automotive battery. It has an adjustable scan mode that significantly reduces the current drawn in key-off. The MAX13362 features an SPI™ interface to monitor the switch status and set the device configuration. Multiple MAX13362s can be cascaded to support any multiple of 24 switches. The MAX13362 is available in a 6mm x 6mm, 40-pin thin QFN package and operates over the -40°C to +125°C temperature range. Features ♦ 9V to 18V Operating Voltage Range with Full Performance ♦ Fully Functional Range of 5.5V to 28V ♦ Switch Inputs Withstand 27V ♦ Switch Inputs Withstand Reverse Battery ♦ Ultra-Low Operating Current 100µA (typ) in Scan Mode ♦ Built-In Switching Hysteresis ♦ Built-In Switch Deglitching ♦ CMOS-Compatible Logic Outputs Down to 3.0V ♦ Interrupt Output to Processor ♦ Configurable Wetting Current (0mA, 5mA, 10mA, or 15mA) for Each Switch Input ♦ AEC-Q100 Qualified Ordering Information Applications Automotive Body Controllers PART Automotive Door Modules MAX13362ATL/V+ Automotive Smart Junction Boxes TEMP RANGE PIN-PACKAGE -40°C to +125°C 40 Thin QFN-EP* (6mm x 6mm) *EP = Exposed pad. +Denotes a lead(Pb)-free/RoHS-compliant package. /V Denotes an automotive qualified part. Typical Application Circuit Pin Configuration ECU CONNECTOR 0.047μF 0.047μF IN0 IN23 IN22 IN21 IN20 IN19 IN18 IN17 IN16 IN15 IN14 IN13 IN12 IN11 IN10 IN9 IN8 IN7 IN6 IN5 IN4 IN3 IN2 IN1 100Ω N.C. N.C. IN6 IN5 IN4 IN3 IN2 IN1 IN0 SD 29 28 27 26 25 24 23 22 21 BATTERY 9V TO 18V 24 SWITCHES, 1 BATTERY-CONNECTED 30 TOP VIEW IN7 31 20 VS IN8 32 19 VS IN9 33 18 GND IN10 34 17 VDD IN11 35 16 GND IN12 36 15 SDI IN13 37 14 CS IN14 38 13 SDO IN15 39 12 CLK IN16 40 11 N.C. MAX13362 VS SPI is a trademark of Motorola, Inc. 6 7 8 9 10 IN20 IN21 IN22 IN23 INT + 5 SD IN19 MICROCONTROLLER /LOGIC CIRCUIT INT 4 CS IN18 CLK 3 SDO IN17 SDI 2 GND 1 OUT VDD N.C. MAX13362 N.C. IN REGULATOR THIN QFN (6mm x 6mm) ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX13362 General Description MAX13362 24-Channel Automotive Switch Monitor ABSOLUTE MAXIMUM RATING VDD, CLK, SDI, CS to GND ......................................-0.3V to +6V VS, SD, INT to GND................................................-0.3V to +40V IN0–IN23 to GND.....................................................-15V to +27V SDO to GND ...............................................-0.3V to (VDD + 0.3V) ESD Protection, All Pins (HBM)............................................±2kV ESD Protection on Pins IN0–IN23 to IEC61000-4-2 Specification (with added 0.047µF capacitor, and/or 100Ω resistor)....±8kV Current Into Any Pin..........................................................±20mA Continuous Power Dissipation (TA = +70°C) (derate 37mW/°C above +70°C)(multilayer board)....2963mW Operating Temperature Range .........................-40°C to +125°C Junction Temperature........................................-40°C to +150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VDD = 5V, VVS = 14V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA =+25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POWER SUPPLY VDD Operating Supply Range VDD VDD Supply Current IDD VS Supply Range VS Undervoltage Lockout Total Supply Current (Flowing into VS and VDD) VS Supply Current in Shutdown Mode VDD Supply Current in Shutdown Mode VVS 3 (Note 1) VUVLO ISUP ISDVS ISDVDD 5.5 V 10 µA 5.5 28 V 3 5.5 V 0.1 tPOLL = 64ms, tPOLL_ACT = 1ms; LP bit in internal register = 0, 24 channels active, all switches open, TA = +25°C 100 170 tPOLL = 64ms, tPOLL_ACT = 1ms; LP bit in internal register = 0, 24 channels active, all switches open 100 200 Continuous polling mode, wetting current set to 5mA 1000 VSD = 0, VVS = 14V, all switches open, TA = +25°C VSD = 0, VVS = 14V, TA = +25°C µA 6 10 µA 0.1 5 µA 3.7 V SWITCH INPUTS Input Voltage Threshold VTH VVS = 5.5V to 28V, measured with 100Ω series resistor for high-side switches Input Hysteresis VH VVS = 5.5V to 28V, measured with 100Ω series resistor for high-side switches Wetting Current Rise/Fall Time Wetting Current IN0–IN23 Input Current IN0–IN23 Input Leakage Current in Shutdown IN4–IN23 Dropout Voltage 2 2.5 tIWETT IWETT IIN_ ILEAKSD VDO15 0.2 V 5 µs Wetting current set to 15mA, 9V < VVS < 18V 12.7 15 17.25 Wetting current set to 15mA, (5.5V < VVS < 9V) or (18V < VVS < 28V) 10.5 15 19.5 16 30 mA VIN_ = 0, TA = +25°C VIN_ = 14V, TA = +25°C (Note 2) 2 VVS = 0 or 14V, VSD = 0, TA = +25°C IWETT = 15mA (Note 3) 2.8 _______________________________________________________________________________________ µA ±2 µA 4.0 V 24-Channel Automotive Switch Monitor (VDD = 5V, VVS = 14V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA =+25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS LOGIC LEVELS INT Output-Voltage Low VOLINT Sinking 1mA SDO Output-Voltage Low VOLSDO Sinking 1mA SDO Output-Voltage High VOHSDO Sourcing 1mA SDO Leakage Current in HighImpedance Mode SDI, CLK, CS Input-Voltage Low SDI, CLK, CS Input-Voltage High ILSDO 0.8 x VDD -1 +1 0.33 x VDD VIH VILSD SD Input High Voltage VIHSD 0.66 x VDD 30 µA V V 0.8 RPD V V V VIL SD Input Low Voltage SDI Internal Pulldown Resistor VCS = 5V 0.4 0.2 x VDD V 50 2.4 V 120 kΩ CLK Pin Leakage ILEAKCLK VCLK = 5V, TA = +25°C 1 µA CS Pin Leakage ILEAKCS VCS = 5V, TA = +25°C 1 µA SD Pin Leakage ILEAKSD VSD = 5V, TA = +25°C 1 µA INT Pin Leakage ILEAKINT VINT = high impedance, TA = +25°C 1 µA THERMAL SHUTDOWN Thermal Shutdown Threshold TSHDN Thermal Shutdown Hysteresis THYST Temperature rising (Note 4) +150 +165 °C 15 °C TIMING Switch Inputs Deglitching Time tGT CLK Frequency Range fCLK (Note 4) 0.01 Falling Edge of CS to Rising Edge of CLK Setup Time tLEAD Polling mode, input rise/fall time < 10ns (Note 4) 100 ns Falling Edge of CLK to Rising Edge of CS Setup Time tLAG Input rise/fall time < 10ns (Note 4) 100 ns tSI(SU) (Note 4) 30 ns SDI Hold Time After Falling Edge of CLK tSI(HOLD) (Note 4) 20 ns Time from Rising Edge of CLK to SDO Data Valid tVALID CSDO = 50pF (Note 3) 70 ns Time from Falling Edge of CS to SDO Low Impedance tSO(EN) (Note 4) 55 ns Time from Rising Edge of CS to SDO High Impedance tSDO(DIS) (Note 4) 55 ns SDI-to-CLK Falling Edge Setup Time 37 50 63 µs 4 MHz _______________________________________________________________________________________ 3 MAX13362 ELECTRICAL CHARACTERISTICS (continued) MAX13362 24-Channel Automotive Switch Monitor ELECTRICAL CHARACTERISTICS (continued) (VDD = 5V, VVS = 14V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA =+25°C.) PARAMETER MAX UNITS tPOLL_ACT SYMBOL -20 +20 % Polling Time Accuracy tPOLL -20 +20 % Time from Shutdown to Normal Operation tSTART 1 ms Polling Active Time Accuracy CONDITIONS MIN TYP 0.1 Note 1: When VVS is above 28V, the wetting current is disabled to limit power dissipation, and the switch inputs are not monitored. When VVS returns, there is a 1ms blanking time before the external switches are polled. Note 2: This current only flows during the polling active time thus the average value is much lower. For example with a polling time of 64ms and a polling active time of 1ms the average current on an input when connected to 14V is typically 16µA x 1/64 = 0.25µA. Note 3: Difference between VS and IN_ voltage when wetting current has dropped to 90% of its nominal value. Note 4: Guaranteed by design. CS tLEAD tLAG CLK tSI(SU) SDI tSI(HOLD) MSB IN tSO(EN) SDO tSDO(DIS) tVALID MSB OUT LSB OUT Figure 1. SPI Timing Characteristics 4 _______________________________________________________________________________________ 24-Channel Automotive Switch Monitor WETTING CURRENT vs. VS VOLTAGE IWETT = 15mA 10 IWETT = 10mA 5 IWETT = 5mA 0 MAX13362 toc02 MAX13362 toc01 15 MAX13362 toc03 20 WETTING CURRENT (mA) 15 10 5 VIN0 10V 0V 10V/div IWETT = 15mA IWETT 0mA 5mA 5mA/div IWETT = 10mA VINT 2V/div IWETT = 5mA VCS 2V/div 0 -40 -20 0 20 40 60 80 100 120 140 VS VOLTAGE (V) TEMPERATURE (°C) WETTING CURRENT (POLLING MODE) VS SUPPLY CURRENT vs. TEMPERATURE (CONTINUOUS MODE) MAX13362 toc04 2600 IWETT = 15mA FOR ALL CHANNELS SUPPLY CURRENT (μA) 5mA 1800 VS SUPPLY CURRENT vs. TEMPERATURE (POLLING MODE) 130 IWETT = 10mA FOR ALL CHANNELS 1400 IWETT = 5mA FOR ALL CHANNELS 1000 IWETT = 0mA FOR ALL CHANNELS 90 200 -40 -20 5.3 40 60 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (°C) 0 20 40 60 80 100 120 140 TEMPERATURE (°C) TEMPERATURE (°C) SWITCH THRESHOLD vs. TEMPERATURE (HIGH SIDE SWITCH) SWITCH THRESHOLD vs. TEMPERATURE (LOW-SIDE SWITCH) 3.3 SWITCH OPEN TO CLOSE 3.2 SWITCH CLOSE TO OPEN 3.1 HIGH SIDE SWITCH 15mA WETTING CURRENT 100Ω INCLUDED 3.0 5.0 -40 -20 80 100 120 140 3.4 MAX13362 toc08 MAX13362 toc07 5.6 20 3.4 SWITCH THRESHOLD (V) SUPPLY CURRENT (μA) 5.9 0 SWITCH THRESHOLD (V) VS SUPPLY CURRENT vs. TEMPERATURE (SHUTDOWN MODE) 6.2 110 600 1ms/div 6.5 120 100 ALL CHANNELS OPEN 4.096ms POLLING TIME 512μs POLLING ACTIVE TIME POLLING TIME = 65.536ms POLLING ACTIVE TIME = 1.024ms ALL CHANNELS OPEN IWETT = 5mA MAX13362 toc09 WETTING CURRENT (5mA/div) 2200 10ms/div MAX13362 toc06 8 9 10 11 12 13 14 15 16 17 18 SUPPLY CURRENT (μA) 5 6 7 MAX13362 toc05 WETTING CURRENT (mA) 20 SWITCH STATUS CHANGE (CONTINUOUS MODE) WETTING CURRENT vs. TEMPERATURE 3.3 SWITCH OPEN TO CLOSE 3.2 SWITCH CLOSE TO OPEN 3.1 LOW-SIDE SWITCH 15mA WETTING CURRENT 3.0 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (°C) -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (°C) _______________________________________________________________________________________ 5 MAX13362 Typical Operating Characteristics (VDD = VSD = 5V, VVS = 14V, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VDD = VSD = 5V, VVS = 14V, TA = +25°C, unless otherwise noted.) SWITCH STATUS CHANGE (POLLING MODE) SWITCH THRESHOLD vs. VS VOLTAGE (LOW-SIDE SWITCH) MAX13362 toc11 MAX13362 toc10 3.5 3.4 SWITCH THRESHOLD (V) MAX13362 24-Channel Automotive Switch Monitor SWITCH OPEN TO CLOSE 3.3 10V 5V/div VIN 0V 3.2 SWITCH CLOSE TO OPEN 3.1 2V/div VINT 0V 3.0 9 10 11 12 13 14 15 16 17 18 2ms/div VS VOLTAGE (V) Pin Description PIN NAME 1, 2, 11, 29, 30 N.C. No Connection. Not internally connected. 3 IN17 Switch Monitor Input Channel 17. Connect IN17 to a ground-connected switch. 4 IN18 Switch Monitor Input Channel 18. Connect IN18 to a ground-connected switch. 5 IN19 Switch Monitor Input Channel 19. Connect IN19 to a ground-connected switch. 6 IN20 Switch Monitor Input Channel 20. Connect IN20 to a ground-connected switch. 7 IN21 Switch Monitor Input Channel 21. Connect IN21 to a ground-connected switch. 8 IN22 Switch Monitor Input Channel 22. Connect IN22 to a ground-connected switch. 9 IN23 Switch Monitor Input Channel 23. Connect IN23 to a battery-connected or ground-connected switch. When used for a battery-connected switch, add a 100Ω series protection resistor to the input. 10 INT Interrupt Output. INT is an open-drain output that asserts low when one or more of the inputs (IN0–IN23) change state and are enabled for interrupts, or when the overtemperature threshold is exceeded. 12 CLK SPI Serial Clock Input 13 SDO SPI Serial Data Output. SPI data is output on SDO on the rising edges of CLK while CS is held low. SDO is high impedance when CS is high. Connect SDO to a microcontroller data input or to a succeeding device in a daisy chain. 14 CS SPI Chip-Select Input. Drive CS low to enable clocking of data into and out of the IC. SPI data is latched into the device on the rising edge of CS. 15 SDI SPI Serial Data Input. SPI data is latched into the internal shift register on the falling edges of CLK while CS is held low. SDI has an internal 50kΩ pulldown resistor. Connect SDI to the SDO of a preceding device in a daisy chain or to the microcontroller data output. 16, 18 GND Ground. Pins 16 and 18 must be connected to ground. VDD Logic Supply Voltage. Connect VDD to a 3.3V or 5V logic supply. Bypass VDD to GND with at least a 0.1µF capacitor placed as close as possible to VDD. 17 6 FUNCTION _______________________________________________________________________________________ 24-Channel Automotive Switch Monitor PIN NAME FUNCTION 19, 20 VS Supply Voltage Input. VS should be protected from reverse battery using a series diode. Bypass VS to GND with a 0.1µF ceramic capacitor placed as close as possible to VS. In addition, bypass VS with a 47µF or greater capacitor. 21 SD Shutdown Input. Drive SD low to place the IC into shutdown mode. Drive SD high for normal operation. SD is battery-voltage compatible. 22 IN0 Switch Monitor Input Channel 0. Connect IN0 to a battery-connected or ground-connected switch. When used for a battery-connected switch, add a 100Ω series protection resistor to the input. 23 IN1 Switch Monitor Input Channel 1. Connect IN1 to a battery-connected or ground-connected switch. When used for a battery-connected switch, add a 100Ω series protection resistor to the input. 24 IN2 Switch Monitor Input Channel 2. Connect IN2 to a battery-connected or ground-connected switch. When used for a battery-connected switch, add a 100Ω series protection resistor to the input. 25 IN3 Switch Monitor Input Channel 3. Connect IN3 to a battery-connected or ground-connected switch. When used for a battery-connected switch, add a 100Ω series protection resistor to the input. 26 IN4 Switch Monitor Input Channel 4. Connect IN4 to a ground-connected switch. 27 IN5 Switch Monitor Input Channel 5. Connect IN5 to a ground-connected switch. 28 IN6 Switch Monitor Input Channel 6. Connect IN6 to a ground-connected switch. 31 IN7 Switch Monitor Input Channel 7. Connect IN7 to a ground-connected switch. 32 IN8 Switch Monitor Input Channel 8. Connect IN8 to a ground-connected switch. 33 IN9 Switch Monitor Input Channel 9. Connect IN9 to a ground-connected switch. 34 IN10 Switch Monitor Input Channel 10. Connect IN10 to a ground-connected switch. 35 IN11 Switch Monitor Input Channel 11. Connect IN11 to a ground-connected switch. 36 IN12 Switch Monitor Input Channel 12. Connect IN12 to a ground-connected switch. 37 IN13 Switch Monitor Input Channel 13. Connect IN13 to a ground-connected switch. 38 IN14 Switch Monitor Input Channel 14. Connect IN14 to a ground-connected switch. 39 IN15 Switch Monitor Input Channel 15. Connect IN15 to a ground-connected switch. 40 IN16 Switch Monitor Input Channel 16. Connect IN16 to a ground-connected switch. — EP Exposed Pad. Connect EP to GND for enhanced thermal performance. _______________________________________________________________________________________ 7 MAX13362 Pin Description (continued) 24-Channel Automotive Switch Monitor MAX13362 Functional Diagram VS VDD MAX13362 SDO IN0 IN1 IN2 IN3 IN4 IN5 IN6 IN7 IN8 IN9 IN10 IN11 IN12 IN13 IN14 IN15 IN16 IN17 IN18 IN19 IN20 IN21 IN22 IN23 1 OF 24 CS CLK SHIFT REGISTER + CONTROL WETTING CURRENT CONTROL INT SD 24 OF 24 SDI REF GENERATOR GND 8 _______________________________________________________________________________________ 24-Channel Automotive Switch Monitor The MAX13362 is a 24-channel automotive contact monitor designed as an interface between mechanical switches and low-voltage microcontrollers or other logic circuits. It features an SPI interface to monitor individual switch inputs and to configure interrupt capability, wetting current, switch configuration (battery-connected or ground-connected), polling time and polling active time. Any switch status change will cause an interrupt signal if the switch is interrupt enabled. The MAX13362 has three modes of operation: continuous mode, polling mode, and shutdown mode. VDD and VS V DD is the power-supply input for the logic input/ output circuitry. Connect VDD to a 3V to 5.5V logic-level supply. Bypass V DD to GND with at least a 0.1µF capacitor placed as close as possible to VDD. VS is the main power-supply input. Bypass VS to GND with a 0.1µF ceramic capacitor placed as close as possible to VS. In addition, bypass VS with a 47µF or greater capacitor. Mechanical Switch Inputs (IN0–IN23) IN0–IN23 are the inputs for remote mechanical switches. The switch status is indicated by the S0–S23 bits in the status register, and each switch input can be programmed to assert an interrupt (INT) by writing to the IE0–IE23 bits in the command register. All switch inputs are interrupt disabled upon power-up. The IN4–IN22 inputs are intended for ground-connected switches. The IN0–IN3 and IN23 inputs can be programmed for either ground-connected switches or CS battery-connected switches by writing to the LH0–LH3 and LH23 bits (see Table 2). The default configuration of the IN0–IN3 and IN23 inputs after power-up is for ground-connected switches. Wetting Current The MAX13362 applies a programmable wetting current to any closed switch to clean switch contacts that are exposed to adverse conditions. The wetting current for each switch can be set to 0mA, 5mA, 10mA, or 15mA by the W_.0 and W_.1 data bits in the command registers (see Table 5) by means of an SPI data transaction. When using wetting current, special care must be taken to avoid exceeding the maximum power dissipation of the MAX13362 (see the Applications Information section). Disabling the wetting current or limiting the active-wetting current time reduces power consumption. The default state upon power-up is with wetting current disabled. Interrupt Output (INT) INT is an active-low, open-drain output that asserts low when any of the switch inputs change state and is enabled for interrupts, or when the overtemperature threshold is exceeded. An external pullup resistor to VDD is needed on INT. INT is cleared when CS is driven low for a read/write operation. However, in polling mode, any switch state change or overtemperature change which occurs during an SPI transaction is stored and causes an additional interrupt after the SPI transaction is over and CS goes high (shown in Figure 2). If VDD is absent, the INT output is functional provided that it is pulled up to a different supply voltage. SWITCH STATUS CHANGE CLK INT NEW INTERRUPT Figure 2. Switch State Change During the SPI transaction _______________________________________________________________________________________ 9 MAX13362 Detailed Description MAX13362 24-Channel Automotive Switch Monitor Serial Peripheral Interface (CS, SDO, SDI, CLK) daisy chaining is possible) and enables data latching only if exactly 32 bits (or an integer multiple thereof) have been clocked in. The MAX13362 operates as a serial peripheral interface (SPI) slave device. An SPI master accesses and programs the MAX13362 by reading/writing the control registers. The control registers are 32 bits wide, have 2 command bits (or register addresses) and 30 data bits (see Table 1). Figure 3 shows the read/write sequence through SPI. The SPI logic counts the number of bits clocked into the IC (using a modulo-32 counter so that Status Register The status register contains the status of the switches connected to IN0–IN23. The status register also contains an overtemperature warning bit, a power-on-reset bit and a device type bit (see Table 1). The status register is accessed by the SPI-compatible interface. CS CLK SDI CB0 CB1 D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 D16 D17 D18 D19 D20 D21 D22 D23 D24 D25 D26 D27 D28 D29 Z DT RST T SDO S0 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 S21 S22 S23 x x x x x Z NOTE: X = UNUSED, Z = HIGH IMPEDANCE. Figure 3. SPI Read/Write Sequence Table 1. Bit Description BIT NAME CB0, CB1 D0–D29 S0–S23 T 10 BIT DESCRIPTION Command bits. Select the internal register to which data bits D0–D29 are to be written. Data bits. Switch state bit. 0 = switch open, 1 = switch closed. Overtemperature bit. When overtemperature occurs, this bit is set to 1. It is reset on the rising edge of CS. RST Power-on-reset bit. It indicates whether the IC has had a power-on-reset since the last SPI read. 0 = device has been reset. RST is set to 1 on the rising edge of CS. DT Device type. 0 = reserved for future use, 1 = MAX13362. ______________________________________________________________________________________ 24-Channel Automotive Switch Monitor The default configuration after power-on is LH_ = 0, ground connected. Table 2. Command Register Map D29 D28 D27 D26 D25 D24 D23 D22 D21 D20 D19 D18 D17 D16 D15 D14 D13 D12 D11 X LP X P3 D5 D4 W23. W22. W21 W20 W19 W18 W17 W16. W15 W14 W13 W12 W11 W10 W9. W8. W7. PA2 PA1 PA0 0 0 .0 .0 .0 .0 .0 0 .0 .0 .0 .0 .0 .0 0 0 0 W6. W5. W4. 0 0 0 W3. 0 W2. W1. W0. 0 0 0 X 0 0 W23. W22. W21 W20 W19 W18 W17 W16. W15 W14 W13 W12 W11 W10 W9. W8. W7. 1 1 .1 .1 .1 .1 .1 1 .1 .1 .1 .1 .1 .1 1 1 1 W6. W5. W4. 1 1 1 W3. 1 W2. W1. W0. 1 1 1 X 0 1 P2 P1 P0 LH2 LH3 LH2 LH1 LH0 IE23 IE22 IE21 IE20 IE19 IE18 IE17 IE16 IE15 IE14 IE13 IE12 IE11 IE10 3 D10 IE9 D9 IE8 D8 IE7 D7 IE6 D6 IE5 IE4 IE3 D3 D2 IE2 IE1 D1 IE0 D0 X NO OPERATION (NO DATA WRITTEN) CB1 CB0 1 0 1 1 LH_: Switch Configuration for IN0–IN3 and IN23 The LH0–LH3 and LH23 bits set the switch configuration for IN0–IN3 and IN23, respectively. Set LH_ to 0 to configure the input channel to ground connected. Set LH_ to1 to configure the input channel to battery connected. P0–P3: Polling Time P0–P3 are used to set the polling time as shown in Table 3. Table 3. Polling Time Setting Table 4. Polling-Active Time Setting PA0–PA2: Polling Active Time PA0–PA2 are used to set the polling active time as shown in Table 4. P3 P2 P1 P0 POLLING TIME (ms) PA2 PA1 PA0 POLLING ACTIVE TIME (µs) 0 0 0 0 Continuous* 0 0 0 64 0 0 0 1 4.096 0 0 1 128 0 0 1 0 4.096 0 1 0 256 0 0 1 1 4.096 0 1 1 512* 0 1 0 0 4.096 1 0 0 1024 0 1 0 1 4.096 1 0 1 2048 0 1 1 0 8.192 1 1 0 4096 0 1 1 1 16.384 1 1 1 4096 1 0 0 0 32.768 1 0 0 1 65.536 1 0 1 0 131 1 0 1 1 262.1 1 1 0 0 524.3 1 1 0 1 1049 1 1 1 0 2097 1 1 1 1 4194 *Default POR Value. *Default POR value. ______________________________________________________________________________________ 11 MAX13362 Command Register Three 32-bit command registers are used to configure the MAX13362 for various modes of operation and are accessed by the SPI-compatible interface (see Table 2). MAX13362 24-Channel Automotive Switch Monitor IE_: Interrupt Enable The IE_ bit programs the switch input channel, IN_, to be interrupt-enabled or interrupt-disabled (0 = interrupt disabled, 1 = interrupt enabled). The default value after power-on is 0. W_.0 and W_.1: Wetting Current W_.0 and W_.1 bits set the corresponding switch channel-wetting current as shown in Table 5. Table 5. Wetting Current Setting W_.1 W_.0 WETTING CURRENT (mA) 0 0 0* 0 1 5 1 0 10 1 1 15 *Default POR value. switches for a preset duration to reduce the power consumption. In shutdown mode, all switch inputs are high impedance and all circuitry is shutdown. Continuous Mode Operation (P0–P3 = 0) In continuous mode, reading of the switch status is initiated by a falling edge on CS. The microcontroller initiates a low pulse on CS to update the MAX13362 switch status register. If INT remains high, no action needs be taken by the microcontroller. If INT goes low, the microcontroller may perform a read operation to read the updated switch status. On the rising edge of CS, INT is updated. To get correct data, the microcontroller must wait 10µs before initiating a switch status read operation. (See Figure 4.) CS LP: Low Quiescent Current Bit In polling mode, when LP is set to 0, the IC is operating with the lowest quiescent current. The channels that are not enabled to interrupt have their wetting current disabled and are not monitored. The first pulse of wetting current after the switch is closed and sampled is 5mA unless the wetting current for that channel is set to 0mA. The default value of LP after power-on is 0. When LP is 1, all channels are monitored and the wetting current for each channel is set to the value determined by W_.0 and W_.1. If the MAX13362 is in continuous mode, LP is ignored. Operating Modes The MAX13362 features three modes of operation: continuous mode, polling mode, and shutdown mode. In continuous mode, the wetting currents (if enabled) are continuously applied to the closed switches. In polling mode, the wetting currents are applied to the closed SWITCH STATUS CHANGE INT UPDATED, PERFORM READ OPERATION INT Figure 4. Continuous Mode Operation Polling-Mode Operation In polling mode (see Figure 5), each switch input is sampled for a programmable polling active time set by the PA0–PA2 bits between 64µs and 4ms (see Table 4). Sampling is repeated at a period set by the P0–P3 bits (from 4ms to continuous, see Table 3). All switch inputs are sampled simultaneously at the end of the polling active time. Wetting currents (if enabled) are applied to closed switches during the polling active time. Therefore, the polling mode reduces the current consumption from the VS power supply to some value dependent on the polling time chosen. POLLING TIME POLLING ACTIVE TIME SWITCH POSITION SAMPLED POLLING ACTIVE TIME GROUND-CONNECTED SWITCH-INPUT SWITCH POSITION SAMPLED INT SWITCH OPEN Figure 5. Switch Sampling in Polling Mode 12 ______________________________________________________________________________________ 24-Channel Automotive Switch Monitor Shutdown Mode In shutdown mode, all switch inputs are high impedance and the external switches are no longer monitored, reducing current consumption on VS to 6µA (typ). The IC resets upon entering shutdown mode and the contents of the command registers are lost. Therefore, any setting other than power-on-reset defaults needs to be reprogrammed after exiting from the shutdown mode. Applications Information Overtemperature Protection If the IC junction temperature exceeds +165°C, an interrupt signal is generated and the wetting currents are disabled to reduce the on-chip power dissipation. During an overtemperature event, the last switch status is retained in internal memory and the switch status is not updated. The interrupt output is cleared when CS goes high, but the overtemperature bit T in the output word remains for as long as the overtemperature condition persists. When the junction temperature drops by 15°C, the wetting currents are re-enabled and there is a 1ms blanking time before the switches can be polled. Reverse-Battery Tolerance The IN0–IN23 switch inputs withstand up to -15V DC voltage without damage. A reverse-battery diode is needed to protect VS as shown in the Typical Application Circuit. SD can be controlled from a bat- tery-level source but should be protected against reverse battery in the application. Wetting Current and Power Dissipation The maximum power dissipation happens when all switch inputs configured with 15mA continuous wetting current are all closed. Assuming the battery voltage is 14V, the corresponding power dissipated by the IC is 24 x 14V x 15mA = 5040mW. This exceeds the absolute maximum power dissipation of 2963mW. In polling mode, the wetting currents are pulsed at the programmed polling time to reduce the total power dissipated in the IC. ISO 7637 Pulse Immunity VS, SD, and IN0–IN23 are potentially exposed to ISO 7637 pulses. Bypass VS with a 0.1µF and a 47µF capacitor. The VS and SD voltage must be limited below 40V during load dump. Bypass IN0–IN23 with at least 0.047µF capacitors at the ECU connector. When IN0–IN3 or IN23 inputs are used with battery-connected switches, a 100Ω series resistor is needed. These external components allow VS, SD, and IN0–IN23 to withstand ISO 7637 pulses in the application circuit. Mechanical Switch Characteristics The MAX13362 is designed to operate with switches that have the following characteristics: 1) Minimum resistance value with switch open (due to leakage): 10kΩ. 2) Maximum resistance value with switch closed: 100Ω. Chip Information PROCESS: BiCMOS ______________________________________________________________________________________ 13 MAX13362 Any switch position change (if the switch is interruptenabled) is signaled through the active-low open-drain INT output. The INT output is cleared when CS goes low. MAX13362 24-Channel Automotive Switch Monitor Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 40 TQFN-EP T4066+5 21-0141 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.