Infineon Technologies TCA785

Overview

TCA785 from Infineon Technologies is a bipolar phase-control IC designed to generate precisely timed trigger pulses for thyristors, triacs, and power transistors in AC power control systems. It supports 0°–180° phase-angle adjustment via analog control voltage (V11), delivers 250 mA output drive at pins 14/15, operates from 8–18 V supply, and functions across –25°C to +85°C ambient. Used in industrial AC controllers and three-phase rectifier gate drives.

For engineers reviewing the TCA785 datasheet, TCA785 pinout, TCA785 application, or TCA785 equivalent, this page provides verified functional specifications, confirmed package mapping (P-DIP-16-1), validated terminal roles, real-world timing behavior (30 µs base pulse, extendable to 180°), and direct alternatives with documented electrical and functional differences.

Technical Context

The TCA785 implements a zero-crossing synchronized ramp generator: line-synchronized input (pin 5) triggers a current-source-charged capacitor (C10 via R9), and comparison against control voltage (pin 11) determines firing angle ϕ. Each half-wave produces a positive output pulse at Q1/Q2 (pins 14/15), with pulse width adjustable up to 180° using external C12 (pin 12).

Logic outputs include inverted versions (pins 2/3/4), a NOR-combined output QZ (pin 7), and a ϕ+180° phase-shifted signal (pin 3). Inhibit (pin 6) disables all outputs; long-pulse mode (pin 13) extends Q1/Q2 to full conduction window. All logic is LSL-compatible and supports three-IC cascading for three-phase operation.

Key Specifications

Pinout & Package

Package: P-DIP-16-1 (Plastic Dual In-line Package, 16-pin, 0.3-inch width, standard through-hole mounting).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar phase-control applications.

Compared with UAA106 and TC785D, the TCA785 offers higher output drive, integrated zero-cross detection, and native three-phase scalability - making it optimal for industrial-grade AC power control where reliability, timing precision, and system-level integration matter.

Availability

TCA785 is available at Aetrix Electronics and suitable for industrial AC motor speed control, three-phase rectifier gate driving, and resistive heating regulation requiring stable component supply across extended production lifecycles.

Supply support for TCA785 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, automotive, and industrial control ICs with global manufacturing and quality certification (IATF 16949, ISO 9001).

The TCA785 belongs to Infineon's legacy bipolar phase-control product line, engineered specifically for robust, high-reliability AC power regulation in harsh industrial environments - emphasizing timing stability, thermal resilience, and direct gate-drive capability.

FAQ

What is the maximum load current the TCA785 can drive directly?

The TCA785 delivers up to 250 mA sink/source at pins 14 and 15 under specified conditions (VS = 12 V, TA = 25°C). This is sufficient to drive gate resistors of SCRs rated up to ~50 A average current or triacs up to ~25 A RMS, assuming typical gate trigger requirements of ≤100 mA peak and ≤5 V threshold. External buffers are required beyond these limits.

Can multiple TCA785 ICs share a single VREF source?

Yes - the internal reference voltage (pin 8, VREF ≈ 3.1 V) is designed to drive up to 10 TCA785 ICs in parallel. This ensures matched ramp generator slopes across devices, eliminating timing skew in multi-phase or redundant configurations. Total VREF load must remain within ±1% regulation tolerance, achieved using low-impedance PCB routing and local decoupling.

How does the inhibit function (pin 6) affect output behavior?

When pin 6 (I) is pulled high (>3.3 V), all primary outputs (Q1, Q2, Q̅1, Q̅2, QZ) are forced low and held inactive; the ramp generator continues running but its output is blocked from reaching logic gates. When pin 6 returns low (<1.7 V), normal phase-controlled operation resumes immediately on the next zero-cross event - no reset or delay is introduced.

Is the TCA785 RoHS compliant and lead-free?

Yes - the P-DIP-16-1 package variant (ordering code Q67000-A2321) is RoHS-compliant and lead-free, meeting EU Directive 2011/65/EU and JEDEC J-STD-609 Category 3. Lead-free soldering profiles (peak 260°C, 10 s max) apply. Full compliance documentation, including material declarations and test reports, is available upon request from Infineon's official product portal.