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STMicroelectronics TSM1012IST
- Part No.:
- TSM1012IST
- Manufacturer:
- STMicroelectronics
- Category:
- Voltage Reference
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
TSM1012IST.pdf
- Description:
- IC VREF SERIES 1% 8MINISO
- Quantity:
- Payment:
- Shipping:
Inventory:4,113
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Product details
Overview
TSM1012IST 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 TSM1012IST datasheet, TSM1012IST pinout, TSM1012IST application, or TSM1012IST equivalent, this device is selected for precision CV/CC feedback in isolated AC-DC power supplies where low quiescent current, high PSRR (65–100 dB), and minimal external components are critical.
Technical Context
The TSM1012IST implements independent voltage and current control loops using two transconductance amplifiers sharing a common open-collector output stage. Its internal 1.25 V reference feeds both loops: one amplifier compares output voltage via a resistor divider (CV+ and CV−), the other compares sensed current via Rsense and a Vref-derived threshold (CC+ and CC−).
Compensation is fully accessible-both op-amp negative inputs and outputs are externally exposed-enabling stable loop tuning for adapter and charger applications. The device features built-in 28 V VCC clamp and achieves 70–85 dB CMRR and 65–100 dB supply rejection over its full operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Voltage reference | 1.25 V ±0.5% (TSM1012A grade); enables precise CV/CC setpoints without external reference |
| Total supply current | 100–180 µA at VCC = 18 V; minimizes auxiliary supply loading in energy-sensitive adapters |
| Supply voltage range | 4.5 V to 28 V; accommodates wide input variations including clamped VCC from flyback snubbers |
| Input offset voltage | 0.5 mV (typ), 2 mV (max); ensures <1% current limit error with typical Rsense values |
| Transconductance gain | 0.5–1 mA/mV (sink only); defines output current response to differential input voltage |
| Common-mode range | 0 V to (VCC − 1.5 V); supports direct sensing across high-side current resistors |
| PSRR | 65–100 dB; rejects ripple and noise on VCC line critical in unregulated auxiliary supplies |
Pinout & Package
Package: SO-8 (Small Outline, 150 mil width), RoHS-compliant ECOPACK®.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VRef (Pin 1) | Analog output | Stable 1.25 V reference source for both CV and CC loop thresholds |
| CC− (Pin 2) | Analog input | Inverting input of current-control op-amp; connected to low side of Rsense |
| CC+ (Pin 3) | Analog input | Non-inverting input of current-control op-amp; tied to Vref-based threshold divider |
| CV− (Pin 4) | Analog input | Inverting input of voltage-control op-amp; connected to output voltage divider midpoint |
| CV+ (Pin 5) | Analog input | Non-inverting input of voltage-control op-amp; tied to Vref for fixed reference |
| GND (Pin 6) | Power supply | 0 V reference for all analog signals and internal biasing |
| OUT (Pin 7) | Analog output | Open-collector sink output shared by both op-amps; drives optocoupler LED |
| VCC (Pin 8) | Power supply | Main supply input with integrated 28 V Zener clamp; powers internal circuitry |
Key Features
| Feature | Design Value |
|---|---|
| Dual transconductance op-amps with ORed outputs | Enables single optocoupler interface for simultaneous CV and CC regulation without external logic |
| Fully accessible compensation nodes | Negative inputs and outputs of both op-amps exposed externally for stable loop tuning per application |
| Integrated 28 V VCC clamp | Eliminates need for external Zener diode when deriving VCC from unregulated flyback winding |
| Low 100–180 µA supply current | Reduces standby power loss and enables use with high-impedance auxiliary windings |
| ±0.5% reference accuracy (TSM1012A) | Ensures tight current limit tolerance (<2% error) without trimming in production battery chargers |
Applications
| USB-C Adapter Feedback | Lithium-Ion Charger Controller |
|---|---|
|
Use Scenario: Secondary-side regulation in 20–65 W USB-C PD adapters with variable output voltage. IC Role / Device Role / Timing Role: Dual-loop CV/CC feedback controller interfacing with optocoupler to adjust primary-side PWM duty cycle. Use Value: Enables ±1% voltage and ±2% current regulation accuracy while maintaining <300 µW no-load consumption. |
Use Scenario: Constant-current/constant-voltage charging for 1–4 cell Li-ion packs in portable medical devices. IC Role / Device Role / Timing Role: Precision analog controller managing charge termination and foldback during CC/CV transition. Use Value: Delivers <0.5% reference drift over temperature, ensuring safe full-charge cutoff across -20 °C to 60 °C ambient. |
| Industrial AC-DC Power Supply | Universal Wall Charger |
|
Use Scenario: Field-replaceable 12 V/2 A industrial adapter requiring long-term calibration stability and EMI resilience. IC Role / Device Role / Timing Role: Isolated feedback element providing high PSRR (≥90 dB) to suppress mains-borne noise on VCC rail. Use Value: Maintains regulation integrity under 10% THD input distortion without additional filtering components. |
Use Scenario: Multi-chemistry wall charger supporting NiMH, Li-ion, and lead-acid with selectable current limits. IC Role / Device Role / Timing Role: Programmable CC threshold generator using external resistor dividers referenced to VRef. Use Value: Allows three distinct current setpoints (500 mA, 1 A, 2 A) with <1% matching between channels via single VRef source. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-loop SMPS feedback controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431 + LM358 | Discrete solution: separate shunt reference + dual op-amp; requires ≥5 external passives for CV/CC | Higher BOM count and layout area; lacks integrated VCC clamp and matched reference/op-amp offsets | Preferred only when legacy designs require pin-compatible TL431 footprint and cost sensitivity outweighs integration benefits |
| UCC3803-1 | Single op-amp + reference; no dedicated CC loop-requires external comparator and logic for current limiting | Needs ≥3 extra components for CC function; no ORed output-requires external wired-OR or logic gate | Chosen when existing designs already use UCC3803-1 and only minor CV loop updates are needed |
Compared with TL431+LM358 and UCC3803-1, the TSM1012IST reduces component count by ≥4, eliminates offset mismatch between CV and CC paths, and integrates VCC protection-directly enabling compact, low-noise, single-optocoupler adapter designs.
Availability
TSM1012IST is available at Aetrix Electronics and suitable for USB-C adapters, lithium-ion battery chargers, and industrial AC-DC power supplies requiring stable component supply, long-lifecycle support, and guaranteed second-source availability.
Supply support for TSM1012IST 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 ICs, sensors, and analog products for industrial, automotive, and consumer markets.
The TSM1012IST belongs to ST's dedicated SMPS secondary-side controller product line, engineered specifically for high-accuracy, low-power CV/CC regulation in isolated flyback converters used in energy-efficient chargers and adapters.
FAQ
What is the maximum sink current capability of the TSM1012IST OUT pin?
The TSM1012IST OUT pin delivers up to 10 mA short-circuit sink current (Ios) when pulled to (VCC − 0.6 V), with typical low output voltage (Vol) of 250–400 mV at 5 mA load. This directly drives standard optocoupler LEDs (e.g., PC817, LTV-817) without external transistor buffering.
Can the TSM1012IST operate with VCC derived solely from an auxiliary winding without external regulation?
Yes-the TSM1012IST includes an internal 28 V Zener clamp on VCC (Pin 8), allowing direct connection to unregulated auxiliary windings. For reliable start-up under light loads, ensure minimum VCC ≥ 4.5 V; transient overshoot beyond 28 V is safely clamped.
How does the TSM1012IST achieve ORing between voltage and current control loops?
The two transconductance op-amps share a common open-collector output stage (Pin 7). When either loop detects overvoltage or overcurrent, its amplifier sinks current into OUT-activating the optocoupler. No external diodes or logic are needed, eliminating timing skew between CV and CC responses.
What is the recommended compensation network for stable CV loop operation?
A series RC network (Rcv1 = 22 kΩ, Cvc1 = 2.2 nF) between CV− (Pin 4) and OUT (Pin 7) provides proven phase margin >45° in typical 5 V/2 A flyback adapters. Compensation is fully customizable-both nodes are externally accessible for fine-tuning per transformer and optocoupler characteristics.
TSM1012IST Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Reference Type:
- Series
- Output Type:
- Fixed
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- -
- Current - Output:
- 2.5 mA
- Tolerance:
- ±1%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- 4.5V ~ 28V
- Current - Supply:
- 50mA
- Current - Cathode:
- -
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MiniSO
TSM1012IST FAQ
1.How can I place an order for TSM1012IST through Aetrix?
Please submit a Request for Quotation (RFQ) for TSM1012IST on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for TSM1012IST reliable?
The price and inventory of TSM1012IST are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TSM1012IST is usually 5 days.
3.What payment methods are accepted for TSM1012IST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TSM1012IST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TSM1012IST?
TSM1012IST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TSM1012IST order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for TSM1012IST?
For technical support, including TSM1012IST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TSM1012IST requirements.
6.How does Aetrix verify that TSM1012IST is sourced from the original manufacturer or authorized distributors?
All TSM1012IST products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TSM1012IST meets industry standards.
7.What is the process for return or replacement of TSM1012IST?
All TSM1012IST units undergo pre-shipment inspection (PSI). If there is an issue with TSM1012IST, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The TSM1012IST part is unused and in its original packaging.
Return procedure for TSM1012IST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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