STMicroelectronics TSM1013IDT

Overview

TSM1013IDT from STMicroelectronics is a dual-op-amp-based constant voltage (CV) and constant current (CC) controller IC for secondary-side feedback in flyback SMPS, integrating a 2.5 V ±0.5% voltage reference, two transconductance op-amps (Gm = 3.5 mA/mV), and sink-only output stages. It operates from 4.5 V to 28 V supply, supports 0–105°C ambient, and enables precise adapter/battery charger regulation with optocoupler isolation.

For engineers reviewing the TSM1013IDT datasheet, TSM1013IDT pinout, TSM1013IDT application, or TSM1013IDT equivalent, key selection criteria include its dual-loop CV/CC control architecture, SO-8 package compatibility, internal 28 V clamp, low 1 mA quiescent current, and direct access to both op-amp inputs/outputs for external compensation.

Technical Context

The TSM1013IDT implements two independent transconductance operational amplifiers: one configured as a non-inverting CV controller referenced to the internal 2.5 V bandgap, the other as an inverting CC limiter using external Rsense and Vref-derived threshold. Both op-amps feature fully accessible negative inputs and outputs for external RC compensation networks (e.g., 22 kΩ + 2.2 nF).

Its architecture enforces ORing of CV and CC outputs into a single sinking node (Cc Out and Cv Out tied internally), ensuring immediate optocoupler activation when either loop exceeds setpoints. The integrated 28 V zener clamp protects Vcc during startup or overvoltage events without requiring external clamping components.

Key Specifications

Pinout & Package

Package: SO-8 (Small Outline Integrated Circuit, 150 mil width), RoHS-compliant, surface-mountable with standard reflow profile.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL431ACDR and UCC3803D, the TSM1013IDT uniquely integrates dual transconductance op-amps and a precision reference in one SO-8 package, enabling true secondary-side CV/CC co-regulation without external active components-reducing solution size by >40% and eliminating loop interaction risks inherent in discrete implementations.

Availability

TSM1013IDT is available at Aetrix Electronics and suitable for USB-C PD adapters, lithium-ion battery chargers, and industrial AC/DC power supplies requiring stable component supply, consistent parametric performance across batches, and long-term manufacturing continuity.

Supply support for TSM1013IDT 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 microcontrollers, power management ICs, analog chips, and sensors for industrial, automotive, and consumer markets.

The TSM1013IDT belongs to ST's dedicated SMPS secondary-side controller product line, engineered specifically to replace discrete op-amp + reference solutions in isolated flyback and forward converter feedback paths.

FAQ

What is the maximum allowable Vcc voltage before internal clamp activation?

The TSM1013IDT incorporates an internal zener clamp rated at 28 V. When Vcc exceeds this value-such as during startup surges or transformer ringing-the clamp activates to limit junction voltage, preventing damage. Absolute maximum rating is 28 V; operation above this risks permanent degradation. External clamping is unnecessary if Vcc stays within 4.5–28 V range.

Can TSM1013IDT drive an optocoupler directly without a series resistor?

No. The Cv Out and Cc Out pins are current-sinking outputs with 200–600 mV low-level voltage at 10 mA sink. A series current-limiting resistor (typically 1–10 kΩ) must be placed between the output and optocoupler LED anode to set forward current (e.g., 5 mA). Omitting it risks excessive LED current and premature optocoupler failure.

How does the TSM1013IDT handle simultaneous CV and CC conditions?

The TSM1013IDT internally ORs Cv Out and Cc Out into a single sinking node. When either op-amp output pulls low-indicating CV or CC violation-the combined sink activates the optocoupler identically. This ensures immediate primary-side response regardless of which limit is breached, with no priority or arbitration logic required.

Is external compensation mandatory for stable loop operation?

Yes. While the TSM1013IDT allows direct access to op-amp inputs and outputs, stability depends on proper external compensation. ST recommends 22 kΩ + 2.2 nF RC networks (Rvc1/Cvc1 for CV; Ric1/Cic1 for CC) per application note AN2195. Uncompensated loops may oscillate or exhibit overshoot, especially under light-load or wide-line conditions.