TIC12400 24-Input Multiple Switch Detection Interface (MSDI) Device With Integrated ADC and Adjustable Wetting Current

1 Features

• Operates with Supply Voltage (V_S) from 6.5 V to 35 V with Over-voltage and Under-voltage Warning
• Monitors up 24 Direct Switch Inputs with 10 Inputs Configurable to Monitor Switches Connected to Either Ground or Supply
• Switch Input Withstands 40 V and Reverse Supply Condition Down to -24 V
• 6 Configurable Wetting Current Settings:
  (0 mA, 1 mA, 2 mA, 5 mA, 10 mA, and 15 mA)
• Integrated 10-bit ADC for Multi-Position Analog Switch Monitoring
• Integrated Comparator with 4 Programmable Threshold for Input Monitoring
• Ultra-low Operating Current in Polling Mode:
  68 μA Typical (t_POLL = 64 ms, t_{POLL_ACT} = 128 μs,
  All 24 Inputs Active, Comparator Mode, All Switches Open)
• Interfaces Directly to MCU Using 3.3 V/5 V Serial Peripheral Interface (SPI) Protocol
• Interrupt Generation to Support Wake-Up Operation on All Inputs
• Integrated Supply and Temperature Sensing
• ±8 kV Contact Discharge ESD Protection on Input Pins per IEC 61000-4-2 With Appropriate External Components
• 38-Pin TSSOP Package

2 Applications

• Signal Measurement
• PLC, DCS and PAC
• Instrumentation

3 Description

The TIC12400 is an advanced Multiple Switch Detection Interface (MSDI) device designed to detect external switch statuses. The TIC12400 supports 24 direct inputs, with 10 inputs configurable to monitor digital I/O switches. 6 wetting current settings can be programmed for each input to support different application scenarios. The TIC12400 features an integrated 10-bit ADC to monitor multi-position analog switches and a comparator to monitor digital switches independently of the MCU. The device supports wake-up operation on all switch inputs to eliminate the need to keep the MCU active continuously, thus reducing power consumption of the system. The TIC12400 supports 2 modes of operations: continuous and polling mode. In continuous mode, wetting current is supplied continuously. In polling mode, wetting current is turned on periodically to sample the input status based on a programmable timer, thus the system power consumption is significantly reduced. The TIC12400 also offers various fault detection and diagnostic features for improved system robustness.

1. For all available packages, see the orderable addendum at the end of the data sheet.

Simplified Schematic