STMicroelectronics TSM1011IDT

Overview

TSM1011IDT from STMicroelectronics is a constant voltage (CV) and constant current (CC) controller IC for secondary-side regulation in flyback battery chargers and AC/DC adapters. It integrates a 2.545 V precision voltage reference, two transconductance op-amps with ORed outputs, and supports 4.5–28 V supply operation. Its current sink output stage enables direct optocoupler drive in isolated feedback loops.

For engineers reviewing the TSM1011IDT datasheet, TSM1011IDT pinout, TSM1011IDT application, or TSM1011IDT equivalent, key selection criteria include its dual-loop CV/CC control architecture, ±0.5% reference accuracy (TSM1011A variant), SO-8 package compatibility, and 2 kV ESD protection-critical for reliable adapter and charger design.

Technical Context

The TSM1011IDT implements two independent transconductance operational amplifiers-one configured for voltage regulation (CV loop) via resistive divider feedback to CV+ and CV−, the other for current limiting (CC loop) using Rsense and a VRef-derived threshold at CC+ and CC−. Both op-amp outputs are internally ORed at the open-collector OUT pin.

Its internal 2.545 V reference (±0.5% for TSM1011A, ±1% for TSM1011) feeds both control loops, enabling precise setpoint generation without external references. The device operates from 4.5 V to 28 V (clamped internally), with full functionality across 0–105 °C ambient temperature.

Key Specifications

Pinout & Package

The TSM1011IDT is housed in an SO-8 (Small Outline) package, RoHS-compliant and ECOPACK® certified, with standard 1.27 mm pitch and thermal resistance R_thJA = 175 °C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar constant voltage and constant current control applications.

Compared with TL431ACDBVR and UCC3803D, the TSM1011IDT uniquely integrates both CV and CC control in a single SO-8 IC with a shared reference and ORed output-reducing component count, improving loop coordination, and enabling tighter regulation (±0.5%) in space-constrained adapters and chargers.

Availability

TSM1011IDT is available at Aetrix Electronics and suitable for smartphone fast charging adapters, laptop AC adapters, and industrial battery maintenance chargers requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for TSM1011IDT 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, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The TSM1011 belongs to ST's dedicated power management IC portfolio for isolated SMPS feedback, engineered specifically to replace multi-component CV/CC solutions in cost-sensitive, high-volume AC/DC adapters and battery chargers.

FAQ

What is the maximum recommended supply voltage for TSM1011IDT?

The absolute maximum DC supply voltage (VCC) is 28 V, enforced by an internal Zener clamp. Operation above this level risks permanent damage. For reliable long-term use, VCC should be limited to ≤26 V under worst-case conditions including ripple and transient spikes.

Can TSM1011IDT regulate both voltage and current simultaneously?

Yes-the two transconductance op-amps operate independently but share a common open-collector output (OUT). When either CV or CC loop demands regulation, the corresponding op-amp pulls OUT low, activating the optocoupler and reducing primary-side duty cycle. This OR logic ensures priority-based, simultaneous enforcement of both limits.

Is external compensation required for stable operation?

Yes-both op-amps require external compensation. The CV loop uses a series RC network (e.g., 22 kΩ + 2.2 nF) between CV− and OUT; the CC loop uses an identical network between CC− and OUT. Uncompensated operation leads to oscillation or slow transient response, especially under light-load conditions.

How does the TSM1011IDT handle start-up and short-circuit conditions?

During start-up or short-circuit, VCC may fall below 4.5 V, disabling internal regulation. In such cases, current limiting relies solely on the primary-side PWM controller. To ensure full protection, designers must either guarantee minimum VCC via auxiliary winding or implement external undervoltage lockout with restart timing.