Infineon Technologies TCA355GXLLA1

Overview

TCA355GXLLA1 from Infineon Technologies is a bipolar monolithic proximity switch IC designed for inductive sensing of metallic targets without physical contact. It integrates oscillator, amplitude detector, hysteresis comparator, and push-pull output stages in a single PG-DSO-8-1 package. Key confirmed parameters: supply voltage range 5–30 V, oscillator frequency 15 kHz–1.5 MHz, open-loop current <0.9 mA, output saturation voltage <0.22 V at 50 mA, and operating ambient temperature –25 °C to +85 °C. It enables flush-mounted industrial proximity sensors for factory automation.

For engineers reviewing the TCA355GXLLA1 datasheet, TCA355GXLLA1 pinout, TCA355GXLLA1 application, or TCA355GXLLA1 equivalent, key selection considerations include its integrated turn-on delay control (pin 7), absence of external integrating capacitor requirement, fixed hysteresis stability over temperature and supply voltage, and compatibility with low-Q coils due to higher sensitivity.

Technical Context

The TCA355GXLLA1 implements a self-oscillating LC resonant circuit interface where metal proximity damps oscillation amplitude, triggering a comparator with fixed hysteresis. Its internal oscillator operates without external timing components but supports frequency tuning via external L/C network connected to pins 1 and 2.

Output logic is complementary: Q outputs high when coil is undamped (no target), low when damped (target present); /Q provides inverted state. Pin 7 (Turn-On Delay) allows RC-controlled power-up delay by adjusting charge current into internal node DD, enabling suppression of false triggers during supply ramp-up.

Key Specifications

Pinout & Package

Package: PG-DSO-8-1 (8-pin, exposed pad, RoHS-compliant, surface-mount SOIC variant).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar inductive proximity switch applications.

Compared with TCA355GXLLA1, TCA305G offers greater configurability at the cost of size and complexity, while TLV3012AIDBVR demands full external circuit design but enables ultra-low-power or high-frequency (>2 MHz) variants beyond TCA355's 1.5 MHz limit.

Availability

TCA355GXLLA1 is available at Aetrix Electronics and suitable for industrial automation, machine safety systems, and conveyor control applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for TCA355GXLLA1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Infineon Technologies is a German semiconductor manufacturer specializing in power management, sensor ICs, and automotive electronics, with leadership in industrial and high-reliability analog solutions.

The TCA series belongs to Infineon's dedicated proximity switch IC product line, engineered specifically for robust, maintenance-free inductive sensing in harsh factory environments - not general-purpose comparators or op-amps.

FAQ

What is the minimum supply voltage required for reliable operation of TCA355GXLLA1?

The TCA355GXLLA1 requires ≥5 V for full functionality with internal voltage reference stabilization. Operation between ~2.5 V and 5 V is possible only if VREF is externally tied to VS, disabling internal regulation. Below ~4.5 V, outputs disable automatically due to built-in UVLO, preventing erratic behavior during brownout.

Can TCA355GXLLA1 drive a relay directly without external transistors?

Yes - each output (Q and /Q) can sink or source up to 50 mA continuously and withstand short circuits for ≥10 seconds. For standard 5 V/10 mA coil relays, direct drive is fully supported. For higher-current relays (>50 mA), an external NPN/PNP pair or MOSFET buffer is required to avoid exceeding absolute maximum ratings.

How does the turn-on delay function work, and what resistor value is recommended?

Pin 7 controls internal charge current into the delay node DD. Connecting a resistor (e.g., 390 kΩ) between pin 7 and VS sets the blanking time. With no resistor (pin 7 tied to VS), delay is minimized. The delay scales approximately linearly with resistance and is independent of supply voltage above 5 V, enabling precise startup synchronization in multi-sensor systems.

Is external temperature compensation required for stable switching distance over temperature?

No - the TCA355GXLLA1's architecture inherently reduces temperature dependence of switching distance. Unlike earlier proximity ICs, it does not require external diode-based TC compensation (D in schematic). This simplifies design and improves long-term stability, especially in environments with ±40 °C ambient swings typical of outdoor or unconditioned factory floors.