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STMicroelectronics VIPER27HN
- Part No.:
- VIPER27HN
- Manufacturer:
- STMicroelectronics
- Category:
- AC DC Converters, Offline Switches
- Package:
- 8-DIP (0.300", 7.62mm), 7 Leads
- Datasheet:
-
VIPER27HN.pdf
- Description:
- IC OFFLINE SWITCH FLYBACK 7DIP
- Quantity:
- Payment:
- Shipping:
Inventory:726
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Product details
Overview
VIPER27HN 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.), 115 kHz switching frequency with ±8 kHz jitter, and <50 mW standby power at 265 Vac - designed for flyback AC-DC converters in auxiliary power supplies for ATX systems, set-top boxes, and DVD players.
For engineers reviewing the VIPER27HN datasheet, VIPER27HN pinout, VIPER27HN application, or VIPER27HN equivalent, this device delivers integrated high-voltage startup, burst-mode operation for energy compliance, hysteretic thermal shutdown (150 °C), brown-out protection (0.45 V threshold), and OVP with digital strobe filtering - critical for reliable low/medium-power SMPS design under IEC 62368 and Energy Star requirements.
Technical Context
The VIPER27HN implements current-mode control with cycle-by-cycle sensing via internal SenseFET architecture, enabling accurate peak-current limiting without external shunt resistors. Its oscillator uses fixed-frequency spread-spectrum modulation (250 Hz rate) to reduce EMI peaks and lower filter component cost.
It features dual over-current protection: primary cycle-by-cycle limit (adjustable via CONT pin resistor) and secondary hiccup-mode OCP (1 A threshold). Brown-out detection (VBRth = 0.45 V) and overvoltage protection (VOVP = 3.0 V, strobed over 4 cycles) operate independently of feedback loop dynamics, ensuring robust fault response during line transients or output faults.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 115 kHz ±8 kHz jitter - reduces EMI spectral peaks and enables smaller EMI filter components. |
| Drain Voltage Rating | 800 V BVDSS - supports universal input (85–265 Vac) without external HV starter or snubber. |
| Standby Power | <50 mW at 265 Vac - meets EU CoC Tier 2 and DOE Level VI no-load energy regulations. |
| Current Limit | 0.7 A typ. (adjustable via RLIM on CONT pin) - sets maximum peak drain current for transformer sizing and diode stress management. |
| OVP Threshold | 3.0 V with 2.2 µs strobe window - rejects noise during MOSFET turn-off, preventing false trips in noisy flyback secondaries. |
| Brown-out Threshold | 0.45 V (hysteresis = 50 mV) on BR pin - disables switching before bulk capacitor discharge causes regulation loss or instability. |
| Thermal Shutdown | 150 °C with 30 °C hysteresis - protects against sustained overload or poor heatsinking without latch-up. |
Pinout & Package
VIPER27HN is housed in a DIP-7 package with exposed drain pins (pins 7 and 8) connected to the metal frame for enhanced thermal dissipation. The copper pour under DRAIN pins is mandatory per ST layout guidelines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (pins 1–2) | Power section source & control ground reference | Common return for all internal circuits; must be low-inductance connection to minimize noise coupling into FB/CONT. |
| VDD (pin 5) | Control section supply input | Charged by internal HV start-up current (−3 mA typ.) from DRAIN; clamped at 23.5 V to protect bias circuitry. |
| CONT (pin 6) | Adjustable current limit & OVP input | Connects to auxiliary winding via ROVP/RLIM; sinking current here lowers cycle-by-cycle current limit or triggers OVP when voltage exceeds 3.0 V. |
| FB (pin 7) | Feedback error amplifier input | Sourced current (−200 µA typ.) enables optocoupler-based regulation; voltage below 0.6 V activates burst mode for ultra-low standby. |
| BR (pin 8) | Brown-out detection input | Monitors scaled bulk voltage; pulls device into low-consumption shutdown if input falls below 0.45 V (hysteresis prevents chatter). |
| DRAIN (pins 7–8) | High-voltage power switch drain | Carries full primary current and HV start-up current; pins thermally tied to package frame - requires PCB copper area for heat spreading. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 800 V avalanche-rugged MOSFET | Eliminates external HV starter and reduces BOM count in universal-input flyback designs. |
| Frequency jittering (±8 kHz @ 250 Hz) | Lowers peak EMI by >10 dB, reducing need for Y-capacitors and common-mode chokes. |
| On-chip soft-start (8.5 ms) | Gradually ramps current limit during power-up to prevent transformer saturation and secondary diode overstress. |
| Burst-mode operation at light load | Reduces standby consumption to <50 mW while maintaining regulated output without audible noise. |
| Hysteretic thermal shutdown | Shuts down at 150 °C and restarts only after cooling to 120 °C - avoids thermal cycling damage during sustained overload. |
Applications
| ATX Auxiliary Power Supply | Set-Top Box SMPS |
|---|---|
Use Scenario: Provides +5 VSB rail in desktop PC power supplies operating across 85–265 Vac input with tight no-load power limits. IC Role / Device Role / Timing Role: Primary-side PWM controller managing flyback topology with self-supplied VDD from auxiliary winding. Use Value: Meets Intel ATX12V spec for <500 mW standby while delivering stable 5 VSB at up to 2.5 A - enabled by burst mode and low IDD_OFF (270 µA). |
Use Scenario: Powers main logic board and tuner in cable/satellite receivers requiring compact, low-cost AC-DC conversion. IC Role / Device Role / Timing Role: Off-line flyback controller with integrated HV MOSFET and OVP - eliminates external sense resistor and protection IC. Use Value: Enables single-layer PCB layout with DIP-7 footprint and achieves <150 mW no-load consumption - critical for CE marking and regional energy labels. |
| DVD Player Power Stage | White Goods Auxiliary Supply |
Use Scenario: Delivers isolated +3.3 V and +12 V rails for servo control, display, and audio subsystems in consumer DVD/Blu-ray players. IC Role / Device Role / Timing Role: Primary-side regulated flyback controller with brown-out detection to prevent erratic behavior during brown-out events. Use Value: Ensures clean power sequencing and graceful shutdown when input dips below 85 Vac - supported by 0.45 V BR threshold and 50 mV hysteresis. |
Use Scenario: Supplies MCU, display, and sensor interfaces in washing machines, refrigerators, and dishwashers with long operational life requirements. IC Role / Device Role / Timing Role: Robust off-line converter with 800 V drain rating and thermal hysteresis - withstands surge and line transient stresses in industrial-grade appliances. Use Value: Achieves >10-year field reliability without derating, validated by ST's 150 °C junction temperature limit and 5 mJ avalanche energy rating. |
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 rating, 65 kHz fixed frequency, no integrated HV startup - requires external HV resistor network. | Lacks brown-out and OVP strobe; needs external circuitry for same protection level as VIPER27HN. | Prefer where lower BVDSS suffices and cost-sensitive designs accept added external components. |
| LNK306P (Power Integrations) | 725 V rating, 66 kHz, integrated HV switcher with frequency folding - no adjustable current limit or BR pin. | Uses primary-side regulation without optocoupler; lacks dedicated brown-out and OVP inputs. | Choose for simplified opto-free designs where burst-mode efficiency and safety certification are prioritized over programmable protection. |
Compared with ICE2QS03G and LNK306P, VIPER27HN provides higher voltage ruggedness (800 V), direct brown-out and OVP pin interfaces with digital filtering, and adjustable current limit - making it optimal for cost-sensitive, certified auxiliary supplies demanding robust line and load fault handling without external protection ICs.
Availability
VIPER27HN 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 manufacturing.
Supply support for VIPER27HN 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, microcontrollers, and analog ICs for industrial, automotive, and consumer markets.
VIPER27HN belongs to ST's VIPer™ family of off-line high-voltage converters - engineered specifically for low-to-medium power AC-DC flyback applications where integration, EMI reduction, and regulatory compliance are critical design drivers.
FAQ
What is the purpose of the BR pin on VIPER27HN?
The BR (Brown-out) pin monitors a scaled version of the rectified input voltage. When the voltage at this pin falls below 0.45 V (with 50 mV hysteresis), the IC shuts down its switching activity to prevent unstable operation during low-line conditions. It can be grounded if unused, and its internal hysteresis ensures noise immunity and prevents oscillation near the threshold.
How does the CONT pin function in VIPER27HN?
The CONT pin serves two roles: (1) adjusting the cycle-by-cycle current limit by sinking current through an external resistor (RLIM), lowering the default 0.7 A limit; and (2) receiving the auxiliary winding voltage for overvoltage protection - triggering shutdown if voltage exceeds 3.0 V for four consecutive OFF periods, with 2.2 µs strobe delay to reject turn-off noise.
Can VIPER27HN operate without an optocoupler?
No - VIPER27HN requires feedback via the FB pin, which sources −200 µA typical current. This necessitates an optocoupler-based secondary-side regulation loop to close the control system. Unlike primary-side sensing controllers, it does not support direct primary feedback and relies on isolated error signal transmission for tight output regulation.
What thermal considerations apply to the DIP-7 package of VIPER27HN?
The DIP-7 package uses pins 7 and 8 as DRAIN terminals connected directly to the internal MOSFET drain and metal frame. ST mandates a minimum 100 mm² copper pour under these pins for heat dissipation. Thermal resistance junction-to-ambient is 100 °C/W on standard FR4, so continuous 12 W operation requires careful heatsinking or derating above 40 °C ambient to maintain TJ ≤ 150 °C.
VIPER27HN 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:
- 115kHz
- 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
VIPER27HN FAQ
1.How can I place an order for VIPER27HN through Aetrix?
Please submit a Request for Quotation (RFQ) for VIPER27HN 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 VIPER27HN reliable?
The price and inventory of VIPER27HN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for VIPER27HN is usually 5 days.
3.What payment methods are accepted for VIPER27HN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for VIPER27HN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for VIPER27HN?
VIPER27HN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your VIPER27HN 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 VIPER27HN?
For technical support, including VIPER27HN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your VIPER27HN requirements.
6.How does Aetrix verify that VIPER27HN is sourced from the original manufacturer or authorized distributors?
All VIPER27HN 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 VIPER27HN meets industry standards.
7.What is the process for return or replacement of VIPER27HN?
All VIPER27HN units undergo pre-shipment inspection (PSI). If there is an issue with VIPER27HN, 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 VIPER27HN part is unused and in its original packaging.
Return procedure for VIPER27HN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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