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STMicroelectronics SRK1001TR
- Part No.:
- SRK1001TR
- Manufacturer:
- STMicroelectronics
- Category:
- Power Supply Controllers, Monitors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SRK1001TR.pdf
- Description:
- ADAPTIVE SYNCHRONOUS RECTIFICATI
- Quantity:
- Payment:
- Shipping:
Inventory:2,900
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Product details
Overview
SRK1001TR from STMicroelectronics is a secondary-side adaptive synchronous rectification controller for flyback converters, supporting QR and mixed CCM/DCM operation with 3.7–32 V VCC range, 185 V DVS sensing capability, and programmable TON/TOFF blanking (0.28–3.9 µs / 0.34–8.7 µs). It drives N-channel MOSFETs in AC-DC adapters and USB PD profile 4 chargers.
For engineers reviewing the SRK1001TR datasheet, SRK1001TR pinout, SRK1001TR application, or SRK1001TR equivalent, key selection criteria include adaptive ZCD-based turn-off timing, low-consumption mode entry via DIS pin or burst-mode detection, VAUX-assisted operation under CC regulation, and SO8 package compatibility with high-voltage drain-sense routing.
Technical Context
The SRK1001TR implements dual-turn-off logic: adaptive ZCD_OFF comparator targeting 300 ns body-diode residual conduction time (Tdiode_off), plus internal timer with 280 ns anticipation (Tant_timer) referenced to DVS rising edge. Its turn-on delay is fixed at 85 ns (TD_On_min), and blanking times are set by external resistors on TON/TOFF pins.
It features VAUX-assisted supply switching below 3.95 V VCC_SO_On, enabling stable operation during constant-current regulation down to 2 V output. Gate drive clamps at 11.6 V (VGDclamp) and delivers 0.6 A source / 1 A sink peak current to drive power MOSFETs directly.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 3.7–32 V - supports wide-input AC-DC supplies and maintains operation during CC regulation voltage droop. |
| DVS Sensing | 185 V max - enables direct high-side drain sensing without external level-shifting circuitry. |
| Quiescent Current | 170 µA in low-consumption mode - reduces no-load losses in battery chargers and USB PD adapters. |
| Gate Drive Clamp | 11.6 V - prevents overvoltage stress on N-MOSFET gate oxide when VCC exceeds 20 V. |
| TON Programming | 0.28–3.9 µs via RTON (33–250 kΩ) - masks ZCD noise during turn-on to avoid premature turn-off. |
| Adaptive Turn-off Target | Tdiode_off = 300 ns - ensures consistent zero-current switching across MOSFET RDS_ON variations and stray inductance. |
| Operating Frequency | Up to 300 kHz - compatible with high-density flyback designs using GaN primary switches. |
Pinout & Package
SRK1001TR is housed in an SO8 package (5.0 × 6.0 mm, 1.27 mm pitch), optimized for thermal dissipation in compact AC-DC layouts and compatible with standard reflow profiles. Pin 1 (DIS/SYNC) supports both disable control and external synchronization; Pin 2 (GD) delivers high-current gate drive directly to SR MOSFET gate; Pin 5 (DVS) requires ≥300 Ω series resistor for HV sensing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 DIS/SYNC | Disable input / sync trigger | Pulling high >4 cycles enters low-consumption mode; rising edge forces immediate SR MOSFET turn-off; internal 5 µA pull-up requires grounding if unused. |
| 2 GD | Gate driver output | Totem-pole stage sourcing 0.6 A / sinking 1 A; clamped at 11.6 V to protect MOSFET gate; must connect directly to SR MOSFET gate. |
| 3 GND | Power return path | Reference for all internal circuits and gate drive current; must be routed near SR MOSFET source to minimize ground loop inductance. |
| 4 VCC | Main supply input | 3.7–32 V operating range; requires local bypass capacitor; UVLO thresholds at 4.3 V (on) and 3.5 V (off). |
| 5 DVS | Drain voltage sense | Accepts up to 185 V referenced to GND; senses SR MOSFET drain via ≥300 Ω series resistor to limit transient current injection. |
| 6 VAUX | Auxiliary supply input | Enables VCC capacitor recharge during CC regulation when VCC falls below 3.95 V; connects to auxiliary winding or DVS-derived rectifier. |
| 7 TOFF | Turn-off blanking programming | Resistor-to-GND sets TOFF_MIN (0.34–8.7 µs); determines post-turn-off noise immunity window before next ZCD evaluation. |
| 8 TON | Turn-on blanking programming | Resistor-to-GND sets TON_MIN (0.28–3.9 µs); masks DVS ringing after turn-on; capacitor ≥100 pF selects CCM/DCM timer mode. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive ZCD turn-off | Maintains 300 ns body-diode conduction time regardless of MOSFET RDS_ON or PCB stray inductance, eliminating current-inversion risk. |
| VAUX-assisted supply | Activates internal switch at VCC_SO_On = 3.95 V to recharge VCC capacitor from auxiliary sources, sustaining SR operation down to 2 V output. |
| Programmable blanking | Independent TON/TOFF resistive programming enables precise noise immunity tuning for diverse transformer layouts and MOSFET types. |
| Low-consumption mode | Enters automatically during burst-mode operation, DIS pin assertion, or SR conduction < TON_MIN + 300 ns - cuts Iq to 170 µA. |
| Fixed-frequency CCM timer | Uses 100 pF on TON pin to enable Tant_timer-based turn-off with 280 ns anticipation, preventing current inversion during high-load transitions. |
Applications
| AC-DC Adapters | USB Power Delivery (Profile 4) |
|---|---|
|
Use Scenario: 65 W laptop adapter operating in QR + CCM hybrid mode with 90–264 VAC input and 20 V output. IC Role / Device Role / Timing Role: Secondary-side SR controller managing N-MOSFET turn-on/turn-off based on DVS sensing and adaptive ZCD threshold to replace Schottky diode. Use Value: Achieves >94% efficiency at full load and <75 mW no-load consumption by entering low-consumption mode during burst cycles. |
Use Scenario: Multi-port USB PD charger delivering 20 V/3 A to Type-C port while maintaining 5 V/3 A on legacy ports. IC Role / Device Role / Timing Role: Synchronous rectifier driver coordinating with primary-side PWM controller to maintain tight CC/CV regulation across load steps. Use Value: Enables compliance with USB PD 3.0 profile 4 (20 V @ 5 A) by sustaining SR operation down to 2 V output during CC phase via VAUX assist. |
| Battery Chargers | Industrial SMPS |
|
Use Scenario: 45 W fast-charging wall adapter for smartphones with dynamic load ranging from 0.1 A to 3 A at 9 V. IC Role / Device Role / Timing Role: Adaptive SR controller detecting body-diode conduction onset and turning off MOSFET at zero-current crossing to minimize reverse recovery loss. Use Value: Reduces conduction loss by 40% vs. Schottky diode and eliminates thermal runaway risk during light-load intermittent charging. |
Use Scenario: 100 W industrial flyback supplying isolated 24 V/2 A for PLC I/O modules with strict EMI requirements. IC Role / Device Role / Timing Role: High-voltage SR controller interfacing with 185 V DVS node and driving 5 mΩ MOSFETs in fixed-frequency CCM/DCM boundary mode. Use Value: Supports EN 55032 Class B EMI limits by minimizing DVS ringing through programmable blanking and adaptive turn-off timing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar secondary-side synchronous rectification controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP6908GJ-Z | Lacks VAUX assist and adaptive ZCD; uses fixed-threshold ZCD with 10 mV hysteresis and no Tdiode_off targeting. | Suitable only for QR-only designs above 5 V output; cannot sustain SR operation below 4 V output or during CC regulation. | Prefer SRK1001TR where VAUX support, adaptive timing, or sub-4 V output operation is required. |
| NCP4306DR2G | Supports only QR operation; no CCM/DCM timer mode; maximum DVS rating 120 V; no DIS/SYNC pin for external disable. | Limited to low-power QR adapters (<30 W); incompatible with USB PD profile 4 or industrial 24 V SMPS requiring 185 V DVS tolerance. | Choose SRK1001TR for mixed-mode operation, higher DVS rating, or system-level disable/sync control. |
Compared with MP6908GJ-Z and NCP4306DR2G, SRK1001TR uniquely combines VAUX-assisted low-Vout operation, adaptive ZCD targeting fixed Tdiode_off, and dual-mode timer logic-enabling robust SR across QR, CCM, and transitional loads in high-density, high-efficiency flyback systems.
Availability
SRK1001TR is available at Aetrix Electronics and suitable for AC-DC adapters, USB PD profile 4 chargers, and industrial SMPS requiring stable component supply, long-term lifecycle assurance, and traceable sourcing for production ramp.
Supply support for SRK1001TR 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, specializing in power management, analog, and microcontroller solutions for industrial, automotive, and consumer markets.
The SRK1001TR belongs to ST's synchronous rectification controller product line, engineered specifically for high-efficiency flyback converters operating across QR, DCM, and CCM modes with emphasis on light-load efficiency and design flexibility.
FAQ
What is the minimum output voltage supported by SRK1001TR in constant-current regulation?
The SRK1001TR supports CC regulation operation down to 2 V output by leveraging its VAUX pin to recharge the VCC capacitor when VCC drops below 3.95 V. This allows sustained synchronous rectification even as output voltage decreases during battery charging phases, avoiding fallback to less efficient diode conduction.
How does the adaptive turn-off mechanism differ from fixed-threshold ZCD comparators?
Unlike fixed-threshold ZCD comparators that trigger turn-off at a voltage level dependent on MOSFET RDS_ON and stray inductance, SRK1001TR's adaptive algorithm dynamically adjusts the ZCD_OFF threshold to maintain a fixed 300 ns body-diode residual conduction time (Tdiode_off), ensuring consistent zero-current switching across varying MOSFET parameters and layout parasitics.
Can SRK1001TR operate without an external capacitor on the TON pin?
Yes - omitting the capacitor on TON pin configures the IC for QR or DCM-only operation, where turn-off is governed solely by the adaptive ZCD_OFF comparator and internal timer referenced to transformer demagnetization time. A 100 pF capacitor enables fixed-frequency CCM/DCM mode with period-estimated timer anticipation.
What is the role of the DIS/SYNC pin beyond disabling the controller?
The DIS/SYNC pin serves dual functions: pulling it high for ≥4 switching cycles forces SR MOSFET turn-off and enters low-consumption mode, while applying a clean positive-going SYNC pulse triggers immediate turn-off independent of ZCD or timer - useful for precise system-level timing coordination or fault shutdown sequences.
SRK1001TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Applications:
- Flyback Power Supplies
- Voltage - Input:
- -
- Voltage - Supply:
- 3.7V ~ 32V
- Current - Supply:
- 17 mA
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
SRK1001TR FAQ
1.How can I place an order for SRK1001TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SRK1001TR 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 SRK1001TR reliable?
The price and inventory of SRK1001TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SRK1001TR is usually 5 days.
3.What payment methods are accepted for SRK1001TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SRK1001TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SRK1001TR?
SRK1001TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SRK1001TR 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 SRK1001TR?
For technical support, including SRK1001TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SRK1001TR requirements.
6.How does Aetrix verify that SRK1001TR is sourced from the original manufacturer or authorized distributors?
All SRK1001TR 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 SRK1001TR meets industry standards.
7.What is the process for return or replacement of SRK1001TR?
All SRK1001TR units undergo pre-shipment inspection (PSI). If there is an issue with SRK1001TR, 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 SRK1001TR part is unused and in its original packaging.
Return procedure for SRK1001TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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