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STMicroelectronics VIPER27LN
- Part No.:
- VIPER27LN
- Manufacturer:
- STMicroelectronics
- Category:
- AC DC Converters, Offline Switches
- Package:
- 8-DIP (0.300", 7.62mm), 7 Leads
- Datasheet:
-
VIPER27LN.pdf
- Description:
- IC OFFLINE SWITCH FLYBACK 7DIP
- Quantity:
- Payment:
- Shipping:
Inventory:5,898
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Product details
Overview
VIPER27LN from STMicroelectronics is an off-line high-voltage PWM controller IC integrating an 800 V avalanche-rugged N-channel power MOSFET, adjustable current-limit protection (0.7 A typ.), 60 kHz fixed switching frequency with ±4 kHz jitter, and <50 mW standby power at 265 Vac - designed for flyback AC-DC converters in auxiliary power supplies for consumer electronics and white goods.
For engineers reviewing the VIPER27LN datasheet, VIPER27LN pinout, VIPER27LN application, or VIPER27LN equivalent, this device delivers integrated high-voltage startup, burst-mode operation for energy compliance, on-board soft-start, hysteretic thermal shutdown, and brown-out protection - all in a DIP-7 package optimized for cost-sensitive, low-to-medium power SMPS designs.
Technical Context
The VIPER27LN implements current-mode PWM control with cycle-by-cycle overcurrent sensing via internal SenseFET architecture and external RLIM resistor adjustment. Its oscillator features spread-spectrum frequency jittering (±4 kHz at 250 Hz) to reduce EMI filter cost and meet conducted emission standards without added components.
It integrates dual-level protection: first-level OCP via CONT-pin-adjustable threshold (0.66–0.74 A), second-level hiccup-mode OCP at 1 A, plus digital strobed OVP (2.7–3.3 V threshold, 2.2 µs sampling delay), brown-out detection (0.41–0.49 V falling threshold), and thermal shutdown at 150–160 °C with 30 °C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Power Section BVDSS | 800 V min - enables direct rectified universal AC input (85–265 Vac) without pre-regulator or voltage divider |
| Switching Frequency | 60 kHz ±4 kHz jitter - balances efficiency, transformer size, and EMI filtering cost in compact adapters |
| Standby Power | <50 mW at 265 Vac - meets Energy Star v2.0 and EU CoC Tier 2 no-load consumption requirements |
| Current Limit Set Point | Adjustable 0.66–0.74 A via RLIM resistor - allows precise peak-current tuning across line/load conditions |
| OVP Threshold | 2.7–3.3 V on CONT pin - digitally strobed and filtered for noise-immune output overvoltage shutdown |
| Brown-out Threshold | 0.41–0.49 V on BR pin - prevents erratic restart during low-input-line sag, ensuring monotonic power-down |
| Thermal Shutdown | 150–160 °C with 30 °C hysteresis - protects against sustained overload or poor heatsinking in enclosed adapters |
Pinout & Package
Package: DIP-7 (dual-in-line, 7-pin, through-hole), with pins 7 and 8 internally connected to DRAIN and bonded to metal frame for enhanced thermal dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1–2) | Device ground / power section source | Common reference for control logic, feedback, and current sense; must be low-impedance PCB plane |
| VDD (Pin 5) | Control section supply | Charged by HV startup current (−3 mA typ.) from DRAIN; clamped at 23.5 V; powers internal logic until auxiliary winding takes over |
| CONT (Pin 6) | Current limit & OVP input | Adjusts cycle-by-cycle OCP threshold via external RLIM; also monitors auxiliary winding for digital OVP detection |
| FB (Pin 7) | Feedback regulation input | Sourced current (−200 µA typ.) enables optocoupler-based loop control; triggers burst mode below 0.6 V |
| BR (Pin 8) | Brown-out protection input | Detects bulk capacitor undervoltage; shuts down non-latching when VBR falls below 0.45 V (typ.) |
| DRAIN (Pins 7–8) | High-voltage power switch drain | Carries full primary current; draws HV startup current; requires large copper pour for thermal management |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 800 V avalanche-rugged MOSFET | Eliminates external HV switch and gate driver, reducing BOM count and layout complexity in <20 W flybacks |
| Frequency jittering (±4 kHz @ 250 Hz) | Spreads EMI energy across spectrum, enabling smaller/cheaper EMI filters and faster EMC certification |
| Adjustable current limit via RLIM resistor | Enables precise peak-current optimization per transformer design without changing IC or layout |
| Strobed digital OVP with 2.2 µs delay | Rejects turn-off transients on auxiliary winding, preventing false trips during normal switching transitions |
| Burst-mode operation at light load | Reduces no-load consumption to <50 mW while maintaining regulated output via gated PWM bursts |
Applications
| ATX Auxiliary Supply | Set-Top Box Power |
|---|---|
Use Scenario: Provides +5 VSB rail in ATX PC power supplies, operating continuously during system sleep. IC Role / Device Role / Timing Role: Primary-side flyback controller managing isolated standby power delivery with burst-mode regulation. Use Value: Meets Intel's <50 mW +5 VSB requirement while eliminating external HV startup circuitry and reducing board area by 30% vs discrete solutions. |
Use Scenario: Powers main logic and tuner circuits in cable/satellite set-top boxes with variable load profiles. IC Role / Device Role / Timing Role: Off-line flyback controller with auto-restart after overvoltage faults caused by tuner load transients. Use Value: Digital OVP strobing prevents nuisance shutdowns during RF front-end switching events, improving field reliability. |
| DVD Player Adapter | Refrigerator Control Board |
Use Scenario: Delivers isolated 12 V and 5 V rails in wall-plug DVD player adapters with tight enclosure thermal limits. IC Role / Device Role / Timing Role: Integrated HV controller with on-chip soft-start (8.5 ms) and thermal shutdown (150 °C). Use Value: Soft-start reduces inrush stress on secondary rectifier and electrolytic capacitors, extending adapter lifetime in unventilated enclosures. |
Use Scenario: Supplies microcontroller and sensor rails in smart refrigerator control boards exposed to ambient temperatures up to 50 °C. IC Role / Device Role / Timing Role: Primary-side controller with brown-out protection (0.45 V BR threshold) and wide input range (85–265 Vac). Use Value: Prevents erratic MCU resets during utility voltage sags common in residential kitchens, ensuring uninterrupted temperature logging. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar off-line flyback controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ICE2QS03G (Infineon) | 700 V MOSFET, 65 kHz fixed freq, no built-in OVP strobing or brown-out input | Lacks digital OVP filtering and BR pin - requires external circuitry for robust OVP in noisy environments | Choose for higher efficiency at full load where 700 V rating suffices and external protection is acceptable |
| LNK306P (Power Integrations) | 725 V MOSFET, 66 kHz, integrated X-cap discharge, but no adjustable current limit or burst-mode threshold control | Uses primary-sensing topology; lacks CONT-pin flexibility for custom OCP tuning or auxiliary-winding OVP | Prefer for ultra-low-cost designs needing basic compliance, but avoid when precise current limit or OVP timing is critical |
Compared with ICE2QS03G and LNK306P, VIPER27LN offers superior integration of noise-immune OVP, dedicated brown-out input, and resistor-adjustable current limit - making it optimal for cost-sensitive, reliability-critical auxiliary supplies where design margin and regulatory pass rate are prioritized over marginal efficiency gains.
Availability
VIPER27LN is available at Aetrix Electronics and suitable for ATX auxiliary power supplies, set-top box SMPS, and DVD player adapters requiring stable component supply, long-term lifecycle support, and RoHS-compliant through-hole packaging.
Supply support for VIPER27LN 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, delivering intelligent power, analog, and microcontroller solutions for industrial, automotive, and consumer markets.
VIPER27LN belongs to ST's VIPer™ family of high-voltage offline controllers - engineered specifically for compact, low-cost, energy-efficient AC-DC conversion in sub-20 W auxiliary and adapter applications.
FAQ
What is the purpose of the BR pin on VIPER27LN?
The BR (Brown-out) pin monitors the rectified input voltage via a resistive divider. When voltage at BR falls below 0.45 V (typ.), the IC shuts down non-latching to prevent unstable operation during low-line conditions. It restarts automatically once BR rises above 0.45 V + 50 mV hysteresis. This ensures clean power-down behavior in fluctuating AC mains environments.
How does the CONT pin function in VIPER27LN?
The CONT pin serves two roles: (1) adjusting the cycle-by-cycle current limit threshold using an external RLIM resistor (0.66–0.74 A range), and (2) monitoring the auxiliary winding voltage for digital overvoltage protection. During MOSFET off-time, it samples the reflected output voltage; four consecutive exceedances of 3.0 V trigger safe auto-restart.
Can VIPER27LN operate without an auxiliary winding?
No - VIPER27LN requires an auxiliary winding to sustain VDD after startup. The internal HV startup circuit only charges VDD initially (−3 mA typical); once VDD reaches 14 V, the power MOSFET begins switching and the auxiliary winding must supply >8.5 V to maintain operation. Without it, VDD drops below 8.0 V and the IC shuts down.
What thermal considerations apply to the DIP-7 package?
The DIP-7 package uses pins 7 and 8 as DRAIN connections bonded directly to the metal frame. To achieve rated 1 W power dissipation at TA < 40 °C, a minimum 100 mm² copper pour (35 µm thick) must be placed under these pins. Thermal resistance junction-to-ambient is 100 °C/W on standard FR4; insufficient copper increases junction temperature and risks premature thermal shutdown.
VIPER27LN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- VIPer™ plus
- Package/Case:
- 8-DIP (0.300", 7.62mm), 7 Leads
- Packaging:
- Tube
- Product Status:
- Active
- Output Isolation:
- Isolated
- Internal Switch(s):
- Yes
- Voltage - Breakdown:
- 800V
- Topology:
- Flyback
- Voltage - Start Up:
- 14 V
- Voltage - Supply (Vcc/Vdd):
- 8.5V ~ 23.5V
- Duty Cycle:
- 80%
- Frequency - Switching:
- 60kHz
- Power (Watts):
- 20 W
- Fault Protection:
- Current Limiting, Over Temperature, Over Voltage
- Control Features:
- -
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 7-DIP
- Mounting Type:
- Through Hole
VIPER27LN FAQ
1.How can I place an order for VIPER27LN through Aetrix?
Please submit a Request for Quotation (RFQ) for VIPER27LN 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 VIPER27LN reliable?
The price and inventory of VIPER27LN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for VIPER27LN is usually 5 days.
3.What payment methods are accepted for VIPER27LN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for VIPER27LN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for VIPER27LN?
VIPER27LN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your VIPER27LN 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 VIPER27LN?
For technical support, including VIPER27LN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your VIPER27LN requirements.
6.How does Aetrix verify that VIPER27LN is sourced from the original manufacturer or authorized distributors?
All VIPER27LN 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 VIPER27LN meets industry standards.
7.What is the process for return or replacement of VIPER27LN?
All VIPER27LN units undergo pre-shipment inspection (PSI). If there is an issue with VIPER27LN, 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 VIPER27LN part is unused and in its original packaging.
Return procedure for VIPER27LN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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