Description

Freescale offers multiple Switch Detection Interface Devices. The PC33972TEWR2 is a switch detection interface with suppressed wake-up. It is designed to detect the closing and opening of up to 22 switch contacts. The switch status, either open or closed, is transferred to the microprocessor unit (MCU) through a serial peripheral interface (SPI). The device also features a 22-to-1 analog multiplexer for reading inputs as analog. The PC33972TEWR2 has two modes of operation, Normal and Sleep. Normal mode allows programming of the device and supplies switch contacts with pull-up or pull-down current as it monitors switch change of state. The Sleep mode provides low quiescent current, making it ideal for automotive and industrial products requiring low sleep state currents. The device has improvements such as a programmable interrupt timer for Sleep mode that can be disabled, switch detection currents of 32 mA and 4.0 mA for switch-to-ground inputs, and an interrupt bit that can be reset.

Specifications and features

• Designed to Operate 5.5 V ≤ VPWR ≤ 28 V
• Switch Input Voltage Range -14 V to VPWR
• Interfaces Directly to Microprocessor Using 3.3 V/5.0 V SPI Protocol
• Selectable Wake-Up on Change of State
• Selectable Wetting Current (32 mA or 4.0 mA for switch-to-ground inputs)
• 8 Programmable Inputs (Switches to Battery or Ground)
• 14 Switch-to-Ground Inputs
• VPWR Standby Current 100 µA Typical, VDD Standby Current 20 µA Typical
• Pb-free 32-terminal suffix EK

Application Scenarios

The PC33972TEWR2 is suitable for various applications where switch detection and analog input reading are required. It can be used in automotive and industrial products that need low sleep state currents. The device can be integrated into microprocessor-based systems that utilize the SPI protocol for communication.

Comparison

- Can detect the closing and opening of up to 22 switch contacts

- Features a 22-to-1 analog multiplexer for reading inputs as analog

- Has two modes of operation: Normal and Sleep, for flexibility in different scenarios

- Provides low quiescent current in Sleep mode, making it ideal for automotive and industrial products

- Includes improvements such as a programmable interrupt timer and resettable interrupt bit

- Limited to operating within a voltage range of 5.5 V to 28 V

- Switch input voltage range is -14 V to VPWR

- Requires direct interface with a microprocessor using the SPI protocol

- Standby currents may not be suitable for ultra-low power applications

- Specific terminal suffix is required for lead-free applications