TIC10024-Q1 Datasheet, PDF (71/81 Pages) Texas Instruments – 24-Input Multiple Switch Detection Interface (MSDI) Device With Adjustable Wetting Current for Automotive Systems

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TIC10024-Q1
SCPS268 – SEPTEMBER 2017
11 Power Supply Recommendations
There are two supply input pins for the TIC10024-Q1: V_S and V_DD. V_S is the main power supply for the entire chip
and is essential for all critical functions of the device. The V_S supply is designed to be connected to a 12-V
automotive battery (through a reverse blocking diode) with nominal operating voltage no greater than 16V. The
V_DD supply is used to determine the logic level on the SPI communication interface, source the current for the SO
driver, and sets the pull-up voltage for the /CS pin. It can also be used as a possible external pull-up supply for
the /INT pin as an alternative to the V_S supply and it shall be connected to a 3 V to 5.5 V logic supply. Removing
V_DD from the device disables SPI communications, but does not impact normal operation of the device.
To improve stability of the supply inputs, some decoupling capacitors are recommended on the PCB. Figure 47
shows an example on the on-board power supply decoupling scheme. The battery voltage (V_BAT) is decoupled
on the Electronic Control Unit (ECU) board using a large decoupling capacitor (C_BUFF). The diode is installed to
prevent damage to the internal system under reversed battery condition. C_VS shall be installed close to the
TIC10024-Q1 for best decoupling performance. The voltage regulator provides a regulated voltage for the digital
portion of the device and for the local microcontroller and its output is decoupled with C_DECOUPLE. Table 28 lists
recommended values for each individual decoupling capacitor shown in the system diagram.
Table 28. Decoupling Capacitor Recommendations
CRC RULE
C_BUFF
C_VBAT
C_VS
C_DECOUPLE
VALUE
100 μF, 50 V rated, ±20%
100 nF, 50V rated, ±10%; X7R
100 nF, 50 V rated
100 nF~1 μF
ECU
connector
VBAT
CVBAT CBUFF CVS
Voltage
Regulator
GND
CDECOUPLE
37 38
VS VS
VDD 19
TIC10024-Q1
VDD
MCU
Electronic Control Unit (ECU)
Copyright © 2016, Texas Instruments Incorporated
Figure 47. Recommended Power Supply Decoupling
Copyright © 2017, Texas Instruments Incorporated
Product Folder Links: TIC10024-Q1
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