STMicroelectronics VIPER17HN

Overview

VIPER17HN from STMicroelectronics is a high-voltage off-line PWM switching regulator IC integrating an 800 V avalanche-rugged N-channel MOSFET, current-mode control, adjustable cycle-by-cycle current limit (0.4 A typ.), 115 kHz fixed switching frequency with ±8 kHz jitter, and <30 mW standby power at 265 VAC - designed for flyback converters in compact AC/DC adapters and auxiliary supplies.

For engineers reviewing the VIPER17HN datasheet, VIPER17HN pinout, VIPER17HN application, or VIPER17HN equivalent, key selection criteria include its DIP-7 package thermal performance (R_thJA = 110 °C/W on standard FR4), brown-out protection (0.45 V threshold), burst-mode operation below 0.45 V_FB, and integrated soft-start (8.5 ms).

Technical Context

The VIPER17HN implements a current-mode flyback controller with dual overcurrent protection: primary-side cycle-by-cycle limiting (adjustable via CONT pin) and secondary-level hiccup-mode OCP (0.6 A threshold). Its oscillator delivers fixed 115 kHz operation with 250 Hz spread-spectrum frequency jittering to reduce EMI peak amplitudes.

Brown-out detection (V_BRth = 0.45 V, hysteresis = 50 mV) disables switching when rectified input falls below safe operating level; thermal shutdown activates at 155 °C with 30 °C hysteresis. Startup is enabled by internal HV generator drawing current from DRAIN pin above 80 V.

Key Specifications

Pinout & Package

VIPER17HN is housed in a 7-pin DIP (Dual In-line Package) with exposed drain pads (pins 7 and 8) thermally connected to the metal frame for enhanced heat dissipation. The package complies with JEDEC MS-001 and supports through-hole mounting with ≥100 mm² copper pour under drain pins.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage flyback controller applications.

Compared with ICE3B0565J and LNK306PN, VIPER17HN offers superior universal-input robustness (800 V), precise current limit tuning, and integrated brown-out - making it optimal for high-reliability auxiliary supplies where input instability and thermal margin are critical.

Availability

VIPER17HN is available at Aetrix Electronics and suitable for AC/DC adapters, TV auxiliary supplies, capacitor-free LED drivers, and set-top box SMPS requiring stable component supply across extended product lifecycles.

Supply support for VIPER17HN 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, microcontrollers, and automotive ICs - with over 40 years of high-voltage analog process expertise.

VIPER17HN belongs to the VIPerPlus family of integrated HV converters, engineered specifically for cost-sensitive, space-constrained offline flyback applications demanding high reliability and regulatory compliance without external HV components.

FAQ

What is the purpose of the CONT pin on VIPER17HN?

The CONT pin serves two critical functions: (1) adjusting the cycle-by-cycle current limit threshold via an external resistor to match transformer design and safety margins; and (2) monitoring auxiliary winding voltage for overvoltage protection using digitally filtered strobed sampling (2.2 µs delay) to reject switching noise. It is not a general-purpose analog input.

How does VIPER17HN achieve <30 mW standby power?

VIPER17HN achieves ultra-low standby power through burst-mode operation triggered when FB voltage falls below 0.45 V, combined with deep UVLO hysteresis (VDD restart threshold = 4.5 V) and reduced HV startup current (0.6 mA vs. 3 mA normal) during fault recovery - minimizing average quiescent draw across universal AC inputs.

Can VIPER17HN replace VIPER22A in existing designs?

No - VIPER17HN (115 kHz, 800 V, DIP-7) and VIPER22A (60 kHz, 730 V, DIP-8) differ in pin count, switching frequency, voltage rating, and protection thresholds. Direct replacement would require PCB redesign, transformer re-optimization, and validation of OVP/Brown-out timing - especially due to missing pin 8 (NC on VIPER17HN vs. VDD on VIPER22A).

What thermal derating applies to VIPER17HN in DIP-7 package?

In DIP-7 on standard single-sided FR4 with 100 mm² copper pour, VIPER17HN's R_thJA is 90 °C/W. At 50 °C ambient, maximum continuous power is limited to ~0.8 W (T_J = 150 °C); above 60 °C ambient, power must be linearly derated to zero at 105 °C ambient per ST's thermal guidelines in DocID14419 Rev 11 Section 4.2.