STMicroelectronics TSM1012IDT

Overview

TSM1012IDT from STMicroelectronics is a dual-loop SMPS controller IC for secondary-side voltage and current regulation in flyback adapters and battery chargers. It integrates a 1.25 V ±0.5% reference, two transconductance op-amps with ORed sink outputs, operates from 4.5 V to 28 V, consumes only 100–180 µA, and supports -40 °C to +105 °C operation.

For engineers reviewing the TSM1012IDT datasheet, TSM1012IDT pinout, TSM1012IDT application, or TSM1012IDT equivalent, this device serves as a low-power, high-precision CV/CC feedback controller where supply rejection (≥65 dB), input offset drift (7 µV/°C), and output short-circuit capability (5–10 mA) directly impact loop stability and charge termination accuracy.

Technical Context

The TSM1012IDT implements two independent transconductance amplifiers sharing a common open-collector output stage - enabling hardware ORing of voltage and current control loops without external logic. Its internal 1.25 V reference feeds both amplifier inputs via external resistor dividers, allowing precise threshold setting for CV (via CV+/CV−) and CC (via CC+/CC−) modes.

Compensation is fully accessible: each amplifier's negative input and output pins are exposed for external RC networks (e.g., 22 kΩ + 2.2 nF), supporting stable loop design across wide load and line variations. The integrated 28 V Zener clamp on VCC protects against overvoltage during start-up or fault conditions in unregulated auxiliary supplies.

Key Specifications

Pinout & Package

Package: SO-8 (Small Outline, 150 mil width), RoHS-compliant ECOPACK®.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar CV/CC feedback controller applications.

Compared with TL431ACDBVR and UCC3803D, the TSM1012IDT uniquely integrates matched CV/CC paths with shared sinking output - reducing system-level component count by ≥4 devices while maintaining galvanic isolation and ±0.5% reference precision essential for USB PD and medical-grade chargers.

Availability

TSM1012IDT is available at Aetrix Electronics and suitable for smartphone fast charging adapters, laptop AC adapters, and industrial battery maintenance chargers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TSM1012IDT 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The TSM1012IDT belongs to ST's dedicated power management analog portfolio, engineered specifically for high-accuracy, low-quiescent-current secondary-side feedback in isolated SMPS - targeting efficiency-critical, safety-certified adapter and charger applications.

FAQ

What is the maximum allowable VCC voltage before the internal clamp activates?

The TSM1012IDT features an integrated Zener clamp with a nominal breakdown voltage of 28 V. When VCC exceeds this threshold under transient or fault conditions, the clamp conducts to limit voltage at the pin. Absolute maximum rating is 28 V, and sustained operation above this level risks permanent damage. Designers must ensure auxiliary supply peaks stay below 28 V or include external clamping.

Can the TSM1012IDT regulate both voltage and current simultaneously in a single output?

Yes - the TSM1012IDT uses hardware ORing of its two transconductance amplifier outputs to enforce the lower of the two regulated values. When either CV or CC loop demands lower output, the shared open-collector OUT pin pulls down the optocoupler LED, signaling the primary controller to reduce duty cycle. This produces the classic square-shaped V-I characteristic required for battery charging.

Is external compensation mandatory, or does the TSM1012IDT have internal frequency compensation?

External compensation is required and fully supported. Both amplifiers expose their inverting inputs and outputs for direct connection of RC networks. No internal compensation is provided. Typical networks use 22 kΩ + 2.2 nF per loop, placed between OUT and CC− or CV−, enabling stable phase margin across 10–100 kHz bandwidths depending on transformer and optocoupler characteristics.

How does the 0.5% reference tolerance translate to overall output voltage accuracy in a typical adapter design?

In a standard flyback adapter with R1/R2 feedback divider, the 0.5% VRef tolerance contributes directly to output voltage error. With careful resistor selection (0.1% tolerance, low TCR), PCB layout, and thermal management, total system accuracy remains within ±1% over -40 °C to +105 °C - meeting IEC 62368-1 and USB PD v3.0 requirements for regulated power supplies.