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STMicroelectronics STCH03L
- Part No.:
- STCH03L
- Manufacturer:
- STMicroelectronics
- Category:
- AC DC Converters, Offline Switches
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
STCH03L.pdf
- Description:
- IC OFFLINE SWITCH FLYBACK 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,103
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Product details
Overview
STCH03L from STMicroelectronics is an offline quasi-resonant (QR) zero-voltage-switching (ZVS) PWM controller for primary-side constant current (CC) regulation in flyback AC-DC converters. It integrates a 650 V HV start-up circuit, supports latched overvoltage protection (OVP), delivers <10 mW standby power at 230 VAC, and operates in SO8 package for smartphone chargers and USB PD fast adapters.
For engineers reviewing the STCH03L datasheet, STCH03L pinout, STCH03L application, or STCH03L equivalent, key selection criteria include latched OVP behavior, primary-sensing CC regulation accuracy, ZCD-based QR timing control, and ultra-low quiescent current (290–335 µA) in burst mode.
Technical Context
The STCH03L implements peak-current-mode control with transformer demagnetization sensing on the ZCD pin to enable valley-switching at turn-on, minimizing switching losses and EMI. Its internal feedforward block uses ZCD current sourcing to compensate for mains voltage variation, enabling line-independent CC regulation without secondary current sensing.
It features adaptive UVLO with dual thresholds (9.5 V turn-on / 7.5 V exit under light load), intelligent frequency jittering (9 kHz modulation), and a dedicated latched OVP mode-distinct from the auto-restart STCH03-triggered after 4 consecutive cycles exceeding 2.5 V on FB, requiring full HV reset to recover.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standby Power | <10 mW at 230 VAC - meets stringent EU CoC Tier 2 and DOE Level VI requirements |
| OVP Mode | Latched (not auto-restart) - ensures safe shutdown during sustained overvoltage faults |
| Max Switching Frequency | 154 kHz top limit - prevents excessive EMI and MOSFET stress at medium loads |
| Burst-Mode IQ | 290–335 µA - enables ultra-low residual consumption during no-load operation |
| HV Start-up Voltage | 50 V typ. - initiates charging of VDD capacitor directly from rectified mains |
| ZCD Trigger Threshold | 60 mV (negative-going edge) - precisely detects transformer demagnetization for ZVS |
| UVP Threshold | 0.55 V typ. - protects against output short-circuit by limiting average current |
Pinout & Package
STCH03L is housed in an SO8 (Small Outline, 8-pin) surface-mount package with standard 1.27 mm pitch and exposed thermal pad (as per ST's SO8 mechanical drawing). Pin 1 is marked with a dot or bevelled corner; pins are numbered counter-clockwise.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 HV | High-voltage start-up input | Withstands up to 650 V; sources 7 mA to charge VDD capacitor when >50 V applied |
| 2 NC | No connect | Internal die isolation; used for PCB creepage/clearance compliance only |
| 3 FB | Feedback control input | Sets current sense threshold; determines burst-mode entry (0.6 V) and OVP latch point |
| 4 ZCD | Zero-current detection & voltage monitor | Detects transformer demagnetization (60 mV trigger); provides line feedforward and OVP/UVP sampling |
| 5 SENSE | Primary current sense input | Compares MOSFET RDS(on) voltage against FB-derived reference; includes 380 ns blanking |
| 6 GND | Signal and gate-drive ground return | Must be star-connected to minimize noise coupling into sensitive analog blocks |
| 7 GD | Gate-driver output | Totem-pole stage drives external MOSFET; 137 mA source / 240 mA sink capability |
| 8 VDD | IC supply rail | Operates from 11.5–23 V; restarts at 4.5 V after fault; clamped to 26.5 V internally |
Key Features
| Feature | Design Value |
|---|---|
| Primary-side constant current regulation | Eliminates secondary shunt regulator and optocoupler current feedback path, reducing BOM cost and component count |
| Latched overvoltage protection | Prevents repeated fault cycling during persistent overvoltage; requires full HV removal to reset |
| 650 V integrated HV start-up | Removes external high-voltage resistor network, cutting no-load dissipation and improving reliability |
| Intelligent burst-mode control | Maintains ZVS-like operation down to ~100 Hz, avoiding audible noise while achieving sub-10 mW standby |
| Adaptive UVLO with dual thresholds | Reduces bias consumption at light load by lowering UVLO exit threshold from 9.5 V to 7.5 V |
Applications
| Smartphone Fast Charging Adapter | USB Power Delivery (PD) Auxiliary Supply |
|---|---|
|
Use Scenario: 18–30 W compact wall adapter delivering programmable 5/9/12/15/20 V outputs via USB-C PD negotiation. IC Role / Device Role / Timing Role: Primary-side QR flyback controller managing CC/CV transition, ZCD-synchronized MOSFET turn-on, and latched OVP for safety-critical output regulation. Use Value: Enables single-chip primary-sensing CC regulation with <10 mW no-load consumption, eliminating secondary current sense IC and reducing total solution size by ≥15%. |
Use Scenario: Standby auxiliary supply powering PD controller, level shifters, and communication logic in multi-port USB-C hubs. IC Role / Device Role / Timing Role: Ultra-low-power offline controller maintaining regulated 5 V/100 mA output independent of main converter activity. Use Value: Delivers stable auxiliary rail with burst-mode IQ of 335 µA, ensuring continuous PD controller operation while meeting IEC 62368-1 no-load energy limits. |
| Set-Top Box (STB) External Power Adapter | Notebook PC Auxiliary Bias Supply |
|
Use Scenario: 12 V/2 A external adapter powering legacy STB platforms with strict CE/EN55032 Class B EMI requirements. IC Role / Device Role / Timing Role: QR ZVS controller implementing frequency jittering (9 kHz) and valley-skipping to suppress narrowband EMI peaks. Use Value: Achieves Class B compliance without Y-capacitor doubling or additional EMI filters, reducing BOM cost and board area. |
Use Scenario: On-board 19 V-to-5 V/3.3 V auxiliary supply for EC, keyboard backlight, and sensor interface in thin-and-light notebooks. IC Role / Device Role / Timing Role: Isolated flyback controller providing galvanically separated bias rails with thermal shutdown (150 °C trip) and UVP for short-circuit resilience. Use Value: Integrates OTP, UVP, and latched OVP in one SO8 device, replacing discrete protection circuits and simplifying layout near high-density CPU/GPU zones. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar offline QR flyback controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STCH03 | Auto-restart OVP (not latched); identical pinout and electrical specs except OVP recovery behavior | Suitable where transient overvoltage events require automatic recovery without manual reset | Select STCH03L only when system-level safety mandates non-autorestart OVP per IEC 62368-1 Annex G |
| MP6004GQ-Z | Higher max frequency (200 kHz); no integrated HV start-up; requires external HV resistor network | Used in higher-power (>45 W) adapters where faster switching enables smaller magnetics | Choose MP6004GQ-Z if design targets >30 W output or needs tighter frequency control; STCH03L preferred for <30 W ultra-low-standby designs |
Compared with STCH03, STCH03L adds mandatory latched OVP for enhanced fault containment, while MP6004GQ-Z trades integrated HV start-up for higher-frequency flexibility-making STCH03L optimal for cost-sensitive, safety-critical sub-30 W USB-C adapters.
Availability
STCH03L is available at Aetrix Electronics and suitable for smartphone fast charging adapters, USB PD auxiliary supplies, and set-top box external power supplies requiring stable component supply, long-term lifecycle support, and certified low-standby performance.
Supply support for STCH03L 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, and analog/mixed-signal devices for industrial, automotive, and consumer markets.
The STCH03L belongs to ST's STCHx family of offline QR controllers, engineered specifically for ultra-low-standby, primary-sensing CC/CV flyback converters in compact AC-DC adapters and USB-C power solutions.
FAQ
What distinguishes STCH03L from STCH03?
STCH03L implements latched overvoltage protection (OVP), meaning it remains disabled until HV and VDD fully discharge after an OVP event. STCH03 uses auto-restart OVP, recovering automatically once VDD drops below 4.5 V. All other electrical parameters, pinout, and package are identical-only the OVP recovery logic differs.
Can STCH03L operate without an optocoupler?
Yes-STCH03L supports primary-side constant current (CC) regulation using ZCD-based line feedforward and FB pin voltage scaling, eliminating the need for optocoupler-based current feedback. However, an optocoupler is still required for precise CV regulation and cross-regulation in multi-output designs.
What is the role of the ZCD pin beyond quasi-resonant triggering?
The ZCD pin serves three critical functions: (1) detecting transformer demagnetization for ZVS turn-on, (2) sourcing current proportional to input voltage for line feedforward compensation, and (3) sampling output voltage at demagnetization end for OVP/UVP-enabling all three protections using a single pin without external components.
How does STCH03L achieve <10 mW standby power at 230 VAC?
It combines four key elements: a zero-power 650 V HV start-up cell (leakage <1 µA), burst-mode operation with 290–335 µA quiescent current, adaptive UVLO that lowers turn-off threshold under light load, and intelligent frequency reduction that scales switching down to ~100 Hz-collectively minimizing all conduction, switching, and bias losses.
STCH03L Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Output Isolation:
- Isolated
- Internal Switch(s):
- No
- Voltage - Breakdown:
- -
- Topology:
- Flyback
- Voltage - Start Up:
- 17 V
- Voltage - Supply (Vcc/Vdd):
- 11.5V ~ 23V
- Duty Cycle:
- 50%
- Frequency - Switching:
- 196kHz
- Power (Watts):
- -
- Fault Protection:
- Over Current, Over Voltage
- Control Features:
- -
- Operating Temperature:
- -25°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 8-SOIC
- Mounting Type:
- Surface Mount
STCH03L FAQ
1.How can I place an order for STCH03L through Aetrix?
Please submit a Request for Quotation (RFQ) for STCH03L 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 STCH03L reliable?
The price and inventory of STCH03L are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STCH03L is usually 5 days.
3.What payment methods are accepted for STCH03L?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STCH03L transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STCH03L?
STCH03L orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STCH03L 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 STCH03L?
For technical support, including STCH03L datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STCH03L requirements.
6.How does Aetrix verify that STCH03L is sourced from the original manufacturer or authorized distributors?
All STCH03L 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 STCH03L meets industry standards.
7.What is the process for return or replacement of STCH03L?
All STCH03L units undergo pre-shipment inspection (PSI). If there is an issue with STCH03L, 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 STCH03L part is unused and in its original packaging.
Return procedure for STCH03L:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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