STMicroelectronics TSM1011AIDT

Overview

TSM1011AIDT 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 (±0.5%), 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 TSM1011AIDT datasheet, TSM1011AIDT pinout, TSM1011AIDT application, or TSM1011AIDT equivalent, key selection criteria include reference accuracy (0.5%), dual-loop compensation accessibility, SO-8 thermal resistance (175 °C/W), ESD rating (2 kV), and CV/CC square-characteristic output behavior in regulated power supplies.

Technical Context

The TSM1011AIDT implements dual independent control loops: one op-amp configures as a voltage controller using external resistor dividers referenced to its internal 2.545 V reference; the second op-amp functions as a current limiter by comparing sensed voltage across Rsense against a threshold derived from the same reference. Both amplifiers feature common-collector (current sink) outputs wired together at the OUT pin.

Compensation is fully external and accessible-each op-amp's negative input and output are brought out to dedicated pins (CV−/CC− and OUT), enabling independent pole-zero tuning. The device operates over 0–105 °C and includes an internal 28 V Zener clamp on VCC to protect against transient overvoltage during start-up or short-circuit conditions.

Key Specifications

Pinout & Package

The TSM1011AIDT is housed in an SO-8 package (ECOPACK® compliant), with 1.27 mm pitch, 5.0 × 6.2 mm body, and exposed pad not present. Thermal performance is characterized at 175 °C/W junction-to-ambient.

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 TSM1011AIDT uniquely delivers factory-trimmed dual-loop regulation in a single SO-8 package-enabling tighter CV/CC coordination, lower BOM count, and higher reliability in isolated SMPS without compromising safety isolation.

Availability

TSM1011AIDT is available at Aetrix Electronics and suitable for smartphone fast charging adapters, laptop AC adapters, and industrial battery maintenance systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for TSM1011AIDT 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 TSM1011AIDT belongs to ST's power management analog controller product line, engineered specifically for high-accuracy, low-BOM secondary-side regulation in isolated flyback converters used in battery chargers and universal adapters.

FAQ

What is the function of the VRef pin on the TSM1011AIDT?

The VRef pin provides a stable, factory-trimmed 2.545 V output with ±0.5% initial accuracy and ≤30 mV drift over 0–105 °C. It serves as the precision reference for both the CV and CC control loops-driving resistor dividers for output voltage setting and generating the current-limit threshold via external resistor networks tied to CC+.

Can the TSM1011AIDT operate without an optocoupler?

No-the TSM1011AIDT is designed exclusively for isolated secondary-side regulation and requires an optocoupler to close the feedback loop to the primary-side PWM controller. Its OUT pin sinks current directly into the optocoupler LED; removing the optocoupler breaks regulation and risks uncontrolled output voltage or current.

How does the ORed output architecture affect CV/CC priority?

The ORed (common-collector) output forces the more restrictive loop-either CV or CC-to dominate regulation. When either op-amp demands higher sink current, the combined OUT node pulls harder on the optocoupler, reducing primary duty cycle. This intrinsic priority ensures immediate current limiting during overload before voltage excursion occurs.

Is external compensation mandatory for stable operation?

Yes-both CV and CC loops require external RC compensation networks connected between their respective negative inputs (CV−, CC−) and the OUT pin. The datasheet specifies typical values (22 kΩ + 2.2 nF per loop), and omitting them results in oscillation or slow transient response due to phase margin loss in the transconductance amplifiers.