STMicroelectronics VIPER17LN

Overview

VIPER17LN from STMicroelectronics is a high-voltage 800 V avalanche-rugged flyback controller IC with integrated power MOSFET, operating at 60 kHz fixed frequency with ±4 kHz jittering, delivering up to 9 W in enclosed adapters and supporting <30 mW standby power at 265 VAC - deployed in AC/DC auxiliary supplies for LCD TVs, LED drivers, and set-top boxes.

For engineers reviewing the VIPER17LN datasheet, VIPER17LN pinout, VIPER17LN application, or VIPER17LN equivalent, key selection criteria include its DIP-7 package thermal performance (R_thJA = 110 °C/W on standard FR4), adjustable current limit via CONT pin, burst-mode operation under light load, and brown-out protection with 0.45 V threshold and 50 mV hysteresis.

Technical Context

The VIPER17LN integrates an 800 V N-channel SenseFET with 24 Ω typical R_DS(on) at 25 °C and implements current-mode PWM control with leading-edge blanking (300 ns) and minimum on-time (400 ns). Its oscillator uses spread-spectrum frequency jittering (±4 kHz at 250 Hz) to reduce EMI peak emissions without external filtering.

Brown-out protection monitors rectified input via BR pin (0.45 V threshold), while OVP uses digitally strobed sampling of the CONT pin during MOSFET off-time to detect overvoltage with 2.2 µs delay and 3.0 V trip level - both protections trigger safe auto-restart with low repetition rate (0.6 mA startup current post-fault).

Key Specifications

Pinout & Package

VIPER17LN is housed in a 7-pin DIP package with exposed drain pins (7 and 8) connected to the metal frame for enhanced thermal dissipation; copper area must be designed under DRAIN pins per layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ICE2QS03G and LNK304P, VIPER17LN offers higher voltage ruggedness (800 V), on-chip current limit tuning, and robust digital OVP - making it optimal for universal-input, safety-critical auxiliary supplies needing regulatory compliance and field reliability.

Availability

VIPER17LN is available at Aetrix Electronics and suitable for AC/DC adapter design, LED driver development, and auxiliary power supply integration requiring stable component supply across industrial, consumer, and white-goods programs.

Supply support for VIPER17LN 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 analog, MCU, power, and sensor solutions for automotive, industrial, and consumer markets.

VIPER17LN belongs to the VIPerPlus family of high-voltage offline controllers - engineered specifically for compact, low-cost, energy-compliant flyback converters in space-constrained consumer and industrial power supplies.

FAQ

What is the purpose of the CONT pin on VIPER17LN?

The CONT pin serves dual functions: (1) adjusting the cycle-by-cycle current limit threshold via an external resistor to match transformer and load requirements, and (2) monitoring the auxiliary winding voltage for digitally strobed overvoltage protection. It sinks current during OVP sampling and must be connected through ROVP and DOVP per Figure 27 in the datasheet.

How does VIPER17LN achieve <30 mW standby power?

VIPER17LN achieves sub-30 mW standby power through burst-mode operation - disabling switching cycles when FB voltage falls below 0.45 V - combined with ultra-low quiescent current (270 µA in UVLO state) and automatic shutdown of the HV startup generator once VDD reaches operating voltage. This eliminates wasteful trickle charging during no-load conditions.

Can VIPER17LN be used in a no-optocoupler, primary-side regulated design?

Yes - VIPER17LN supports primary-side regulation using the CONT pin to sample auxiliary winding voltage during MOSFET off-time. The internal OVP circuit uses this signal with 2.2 µs strobe delay and digital filtering to infer output voltage, eliminating the need for optocoupler-based feedback in many auxiliary and LED driver applications.

What thermal derating applies to VIPER17LN in DIP-7 package?

In DIP-7 package on standard single-sided FR4 (100 mm² copper), VIPER17LN has R_thJA = 90 °C/W. At 50 °C ambient, maximum continuous power is limited to ~5.6 W before junction temperature exceeds 150 °C - consistent with the 5 W open-frame rating in Table 2. Heatsinking under DRAIN pins improves performance by lowering R_thJP to 40 °C/W.