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STMicroelectronics TSM1051CD
- Part No.:
- TSM1051CD
- Manufacturer:
- STMicroelectronics
- Category:
- Battery Chargers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TSM1051CD.pdf
- Description:
- IC BATT CONTRL 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,898
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Product details
Overview
TSM1051CD from STMicroelectronics is a constant voltage (CV) and constant current (CC) controller IC for secondary-side feedback in flyback SMPS, used in AC/DC adaptors and battery chargers. It integrates dual transconductance op-amps with ORed outputs, a 1.210 V ±0.5% bandgap voltage reference, and a –200 mV current-sense threshold. Delivers precision regulation with only three external components: voltage-divider resistors, sense resistor, and optional RC compensation.
For engineers reviewing the TSM1051CD datasheet, TSM1051CD pinout, TSM1051CD application, or TSM1051CD equivalent, this device supports accurate CV/CC loop control in space-constrained power supplies where low-voltage operation (2.5–12 V VCC), high mains rejection, and minimal BOM count are critical design requirements.
Technical Context
The TSM1051CD implements two independent control loops: one voltage loop using an internal 1.210 V reference and transconductance gain Gmv = 3.5 mA/mV, and one current loop referenced to –200 mV with transconductance gain Gmi = 7 mA/mV. Both op-amp outputs are wired in common-collector (ORed) configuration to drive a single current-sink output stage.
It operates from 2.5 V to 12 V supply, features low input bias currents (50 nA at Vctrl, 25 µA at Ictrl), and enables full external compensation via accessible inverting inputs and output node. The SO-8 package supports higher thermal dissipation (RthJA = 130 °C/W) than SOT23-6, enabling stable operation up to 85 °C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Voltage reference | 1.210 V ±0.5% at 25 °C; sets precise CV threshold via R1/R2 divider - enables ±1% output voltage accuracy over temperature |
| Current sense threshold | –200 mV ±2% at 25 °C; defines CC trip point - allows accurate current limit setting with Rsense = Vsense/Ilim |
| Gmv (Vctrl gain) | 3.5 mA/mV; converts 1 mV error at Vctrl into 3.5 mA sink current - provides linear, predictable voltage loop response |
| Gmi (Ictrl gain) | 7 mA/mV; converts 1 mV error at Ictrl into 7 mA sink current - delivers fast, high-gain current limiting action |
| Output stage | Sinking-only OUT pin; 50 mA short-circuit current, 200 mV VOL @ 10 mA - drives optocoupler LED directly without external transistor |
| Supply range | 2.5 V to 12 V VCC; supports wide-input auxiliary supplies - eliminates need for dedicated LDO in many adaptor designs |
| Total supply current | 2 mA typical; excludes sinking current - enables low-power operation and reduces self-heating in sealed enclosures |
Pinout & Package
Housed in an SO-8 (Small Outline-8) package per JEDEC MO178AB, with 1.27 mm lead pitch, 5.0 mm × 4.0 mm body, and 1.65 mm max height. RoHS-compliant ECOPACK® with lead-free second-level interconnect.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Vctrl (Pin 1) | Voltage loop inverting input | Connected to mid-point of R1/R2 divider; deviation from 1.210 V generates proportional sink current to regulate output voltage |
| Gnd (Pin 8) | Power and signal reference | 0 V return for all analog circuitry and supply - must be low-impedance connection to minimize noise coupling into CV/CC loops |
| Out (Pin 7) | Current-sink output | Drives optocoupler LED cathode; sinks up to 50 mA - no external transistor needed; series RLED limits current under high VCC |
| Ictrl (Pin 6) | Current loop inverting input | Connected to high-side of sense resistor; voltage drop below –200 mV triggers CC mode - enables accurate foldback or constant-current charging |
| Vsense (Pin 3) | Current loop non-inverting reference input | Internally tied to –200 mV reference; used to bias sense resistor low-side - ensures precise current threshold independent of ground bounce |
| VCC (Pin 2) | Positive supply rail | Power source for internal reference and op-amps; must stay within 2.5–12 V - can be derived from auxiliary winding or local LDO |
| Nc (Pin 4) | No connect | Not internally bonded - must remain unconnected to avoid parasitic coupling or mechanical stress on bond wire |
| Nc (Pin 5) | No connect | Not internally bonded - floating; no routing or copper pour required beneath this pad |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent CV/CC control loops | Enables single-chip compliance with USB PD, QC, and proprietary fast-charge protocols requiring both voltage and current regulation stages |
| ORed op-amp outputs | Guarantees that whichever loop (voltage or current) demands stronger correction dominates the OUT pin - prevents conflict and ensures safe foldback behavior |
| Low external component count | Only R1/R2 divider, Rsense, and optional RC network required - reduces BOM cost, PCB area, and qualification effort vs discrete solutions |
| Full external compensation access | Vctrl and Ictrl inverting inputs + OUT pin allow independent tuning of CV and CC loop stability - avoids oscillation during transient load steps |
| High AC mains rejection | Internal architecture minimizes sensitivity to primary-side ripple - maintains tight regulation even with low-cost transformer designs and minimal input filtering |
Applications
| USB-C Adaptor | Smartphone Battery Charger |
|---|---|
|
Use Scenario: 20 W USB-C wall adapter with programmable 5/9/12 V output and 3 A current limit. IC Role / Device Role / Timing Role: Secondary-side CV/CC feedback controller interfacing with optocoupler to regulate flyback transformer output. Use Value: Enables ±1% voltage accuracy and ±3% current limit accuracy across line/load/temperature - meets USB PD 3.0 specification without trimming. |
Use Scenario: Compact 10 W smartphone charger with CC/CV lithium-ion charging profile and thermal derating. IC Role / Device Role / Timing Role: Dual-loop regulator managing constant-current bulk charge and constant-voltage termination phases. Use Value: Precise –200 mV current threshold allows accurate 2 A CC setting with standard 1206 Rsense; eliminates need for external current DAC or microcontroller. |
| Laptop AC Adapter | Industrial Power Supply Module |
|
Use Scenario: 65 W laptop adapter supporting 20 V/3.25 A output with overvoltage and overcurrent protection. IC Role / Device Role / Timing Role: Primary feedback supervisor ensuring output remains within safety limits during dynamic load changes and fault conditions. Use Value: ORed output architecture guarantees immediate optocoupler activation if either voltage exceeds 20.5 V or current exceeds 3.35 A - meets IEC 62368-1 creepage and fault response requirements. |
Use Scenario: DIN-rail mounted 24 V/2 A industrial SMPS for PLC I/O modules requiring long-term reliability and EMI robustness. IC Role / Device Role / Timing Role: Isolated secondary-side regulation element decoupled from primary controller for enhanced safety and EMC performance. Use Value: Low 2 mA quiescent current and SO-8 thermal resistance (130 °C/W) enable continuous operation at 70 °C ambient without derating - extends MTBF in enclosed cabinets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant voltage and constant current control applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431 + LM358 | Discrete solution requiring ≥6 external components; no integrated –200 mV current reference or ORed outputs - needs external logic for CV/CC arbitration. | Used in legacy adaptors where cost-per-unit is prioritized over board space and design cycle time. | Select only when redesigning existing TL431-based platforms and BOM flexibility outweighs integration benefits. |
| UCC28704 | Primary-side digital controller with integrated HV start-up, QR control, and active clamp - no optocoupler needed; higher system efficiency but requires transformer redesign. | Targeted at new high-efficiency (>88%) designs where eliminating optocoupler improves reliability and reduces bill-of-materials. | Choose when upgrading to primary-side regulation and optimizing for efficiency, not when reusing existing flyback transformer and optocoupler layout. |
Compared with TL431+LM358, TSM1051CD reduces component count by 60% and eliminates CV/CC arbitration logic; versus UCC28704, it retains proven optocoupler-based isolation while offering lower design risk for cost-sensitive, volume production of legacy-compatible adaptors.
Availability
TSM1051CD is available at Aetrix Electronics and suitable for USB-C adaptors, smartphone battery chargers, and industrial DIN-rail power supplies requiring stable component supply, long-lifecycle support, and SO-8 thermal performance.
Supply support for TSM1051CD 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 TSM1051 belongs to ST's dedicated AC/DC controller product line, engineered specifically for secondary-side CV/CC regulation in isolated flyback converters targeting compact, low-cost, and high-reliability power adapters and chargers.
FAQ
What is the function of the Vsense pin on TSM1051CD?
The Vsense pin (Pin 3) is the non-inverting input of the internal current-sense amplifier and is internally biased to –200 mV. It connects to the low-side of the external sense resistor to establish the current-limit threshold. Unlike a generic comparator input, it forms part of a precision transconductance stage with 7 mA/mV gain and matched internal resistor dividers for ±2% threshold accuracy over temperature.
Can TSM1051CD operate with VCC below 3 V?
Yes - the device is specified down to 2.5 V VCC and functions reliably at this minimum, enabling use with low-dropout auxiliary windings or capacitive-dropper supplies. At 2.5 V, total supply current remains ≤2.2 mA, and output sink capability is reduced to ~27 mA, which is sufficient to drive most PC817-class optocouplers with appropriate RLED sizing.
How does the ORed output architecture prevent CV/CC conflict?
The two internal transconductance op-amps share a common collector output stage driving the OUT pin. When either loop demands increased sink current - e.g., voltage rises above setpoint or current exceeds limit - its output pulls the shared node lower. This inherent wired-OR ensures the more urgent condition always dominates, eliminating race conditions and guaranteeing monotonic foldback behavior without external arbitration logic.
Is TSM1051CD suitable for constant-power applications?
No - the TSM1051CD implements strictly constant-voltage and constant-current regulation with square-law V-I output characteristics. It lacks built-in power calculation, multiplication, or adaptive reference scaling. For constant-power control (e.g., PoE PSE), a dedicated digital controller or analog multiplier-based solution is required; this device supports only CV+CC boundary operation.
TSM1051CD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Battery Chemistry:
- -
- Number of Cells:
- -
- Current - Charging:
- Constant
- Programmable Features:
- -
- Fault Protection:
- -
- Charge Current - Max:
- -
- Battery Pack Voltage:
- -
- Voltage - Supply (Max):
- 12V
- Interface:
- -
- Operating Temperature:
- 0°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TSM1051CD FAQ
1.How can I place an order for TSM1051CD through Aetrix?
Please submit a Request for Quotation (RFQ) for TSM1051CD 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 TSM1051CD reliable?
The price and inventory of TSM1051CD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TSM1051CD is usually 5 days.
3.What payment methods are accepted for TSM1051CD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TSM1051CD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TSM1051CD?
TSM1051CD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TSM1051CD 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 TSM1051CD?
For technical support, including TSM1051CD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TSM1051CD requirements.
6.How does Aetrix verify that TSM1051CD is sourced from the original manufacturer or authorized distributors?
All TSM1051CD 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 TSM1051CD meets industry standards.
7.What is the process for return or replacement of TSM1051CD?
All TSM1051CD units undergo pre-shipment inspection (PSI). If there is an issue with TSM1051CD, 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 TSM1051CD part is unused and in its original packaging.
Return procedure for TSM1051CD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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