VIPER38LDTR - 800V Offline Flyback Converter | STMicroelectronics
N.º da peça: VIPER38LDTR ✓ Ativo| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $1.85 | $1,85 |
| 10 | $1.66 | $16,60 |
| 100 | $1.42 | $142,00 |
| 500 | $1.18 | $590,00 |
| 1.000 | $0.98 | $980,00 |
VIPER38LDTR Visão geral
An AC/DC off-line switcher is a power-supply IC that converts rectified mains voltage into a regulated DC rail directly, replacing a discrete MOSFET, gate driver, PWM controller, and current-sense amplifier with one monolithic device. Within the broader IC taxonomy it belongs to the VIPerPlus family of integrated switchers, which sits under AC/DC converters -> power management ICs -> power semiconductors. This category is essential for low-power isolated and non-isolated SMPS designs where board area, BOM count, and standby consumption are critical concerns, especially under modern energy-saving standards such as Energy Star, EuP, and CoC Tier-2.
Key features of the VIPER38LDTR include 800 V minimum drain breakdown voltage (avalanche-rugged), selectable OCP threshold (I_Dlim), fixed 60 kHz PWM operation, very low standby consumption, burst-mode operation under light load, and built-in thermal shutdown. The integration removes dozens of discrete components, allowing a complete 5 V/300 mA auxiliary supply to fit on a PCB area below 100 mm².
The architecture combines a vertical power MOSFET with an analog PWM controller on the same die, enabling tight current-mode feedback and eliminating the gate-drive parasitic losses that plague discrete solutions. The avalanche-rated MOSFET absorbs the energy of transformer leakage inductance spikes, removing the need for an external TVS clamp diode in many designs.
Typical applications include auxiliary supplies for white goods and appliance standby rails, low-power industrial control supplies, IoT smart-home gateways fed from AC mains, LED driver auxiliary rails, and metering/telemetry modules. The wide input range makes the part robust against under-voltage brownout conditions on weak AC grids.
Designers should note that the device requires a current-sense resistor on the source pin and an external bootstrap capacitor. Pay close attention to primary-side Snubber design and to thermal copper area under the exposed die pad to ensure the 800 V MOSFET remains within SOA during line-surge events.
This page synthesizes distributor pricing, datasheet electrical parameters, drop-in alternatives (VIPER38LD, VIPER38HD, and the wider VIPerPlus family), and practical SMPS design notes not found in the manufacturer datasheet alone.
Alternativas drop-in para VIPER38LDTR — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
VIPER38LD
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
VIPER38HD
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
VIPER37LD
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
VIPER28LD
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
VIPER38LDTR Classificações máximas e características elétricas
| Topologia | Offline Flyback |
| Frequência de comutação | 60 kHz (fixed) |
| Tensão de ruptura dreno-fonte | 800 V (avalanche-rugged) |
| Input Voltage AC Min | 8.5 VAC |
| Input Voltage AC Max | 23.5 VAC |
| Output Power (typical) | 1.5 W |
| Configuração de saída | Non-isolated / Flyback |
| Control Mode | PWM Current-Mode |
| OCP Threshold | Selectable (I_Dlim) |
| Light-Load Operation | Burst mode |
| Encapsulamento | NSOIC-16 (16-SO) |
| Faixa de temperatura de operação | -40 C to +150 C (junction) |
| Family | VIPerPlus |
| Product Type | Peak power high-voltage converter |
| Tipo de montagem | Surface Mount |
| Nível MSL | 3 (per JEDEC J-STD-020, manufacturer data not supplied) |
Configuração de pinos do VIPER38LDTR
| Pino 1 | DRAIN — High-voltage MOSFET drain (800 V avalanche-rugged) |
| Pino 2 | SOURCE — Power MOSFET source / signal ground reference |
| Pino 3 | VCC — Supply voltage for control circuitry (decoupled to GND) |
| Pino 4 | COMP — Compensation network for current-mode loop |
| Pino 5 | FB — Feedback input from optocoupler / auxiliary winding |
| Pino 6 | OCP — Over-current protection threshold selection |
| Pino 7 | CS — Current-sense input (external sense resistor to SOURCE) |
| Pino 8 | TOFF — Off-time / blanking capacitor pin |
| Pino 9 | GND — Signal ground |
| Pino 10 | NC — Not connected (per datasheet) |
| Pino 11 | NC — Not connected (per datasheet) |
| Pino 12 | NC — Not connected (per datasheet) |
| Pino 13 | NC — Not connected (per datasheet) |
| Pino 14 | NC — Not connected (per datasheet) |
| Pino 15 | NC — Not connected (per datasheet) |
| Pino 16 | DRAIN — High-voltage MOSFET drain (alternate thermal/electrical tie-in) |
Aplicações típicas
VIPER38LDTR é adequado para 6 aplicaçãos: White Goods Auxiliary Standby Rail, IoT Smart-Home Gateway Power Supply, LED Driver Auxiliary Supply, Industrial Sensor & Metering Telemetry Power, Appliance User-Interface Module, Battery-Charger Aux Supply for Power Tools.
White Goods Auxiliary Standby Rail
The VIPER38LDTR is a strong fit for 5 V/300 mA standby rails in washing-machine, dishwasher, and oven control boards where the AC mains is the only power source. Its integrated 800 V avalanche-rated MOSFET tolerates universal mains inputs (85-265 VAC after rectification) and the burst-mode standby keeps wall-plug consumption below the 50 mW Energy Star ceiling. Compared with discrete flyback solutions, the VIPerPlus monolithic integration removes the gate driver and discrete MOSFET, shrinking the PCB to a quarter of the previous footprint and reducing BOM line items by about 30%.
Recomendado
IoT Smart-Home Gateway Power Supply
Smart-home hubs, Wi-Fi bridges, and Zigbee coordinators fed directly from the mains benefit from the VIPER38LDTR's ultra-wide input range (8.5-23.5 VAC bias, extending to universal mains) and low standby current under burst mode. The 60 kHz fixed switching frequency lets designers use small ferrite transformers and meet EN 55022 Class B conducted emissions without complex filtering. Output regulation accurate to plus or minus 5% under 10% line variation is achievable across global AC networks, supporting worldwide SKU consolidation for gateway OEMs.
Recomendado
LED Driver Auxiliary Supply
Constant-current LED drivers in commercial fixtures (downlights, troffers, streetlights) use the VIPER38LDTR as an auxiliary standby rail to power the control MCU, occupancy sensors, and DALI communication interface while the main LED current is off. The burst-mode operation at light load keeps standby below 50 mW, satisfying the EU 2019/2020 Ecodesign directive for lighting. The 800 V avalanche MOSFET absorbs transformer leakage spikes that occur during mains surge events, increasing field reliability in outdoor and industrial luminaires.
Recomendado
Industrial Sensor & Metering Telemetry Power
Smart electricity meters, gas meters, and industrial PLCs require an isolated or non-isolated auxiliary rail that survives harsh grid conditions. The VIPER38LDTR's 800 V avalanche rating handles sustained over-voltage from 265 VAC brownout transients and induction spikes on long mains runs. The fixed 60 kHz PWM and selectable I_Dlim allow precise short-circuit behavior in utility-meter environments, where the auxiliary supply must operate for 15+ years without field service.
Recomendado
Appliance User-Interface Module
Display modules, touch panels, and Wi-Fi connectivity boards in ovens, refrigerators, and induction hobs use the VIPER38LDTR to generate a clean 5 V or 3.3 V rail from universal mains. The 800 V monolithic integration simplifies safety isolation certification and the selectable current-limit pin lets one BOM cover multiple SKUs across product lines. Under no-load the part enters burst mode, which is essential for Energy Star and 2019/2020 EU 2009/125/EC standby compliance in connected appliances.
Recomendado
Battery-Charger Aux Supply for Power Tools
Cordless drill and outdoor-tool chargers need a continuous 5 V supply for interface LEDs, fuel-gauge ICs, and wireless authentication modules while the main battery-charging converter operates. The VIPER38LDTR's current-mode control provides clean auxiliary power that does not inject ripple into the measurement circuitry of the charging IC. Its non-isolated topology shrinks the charger footprint and weight, suiting the small-form-factor requirements of modern 18 V to 60 V power-tool battery chargers.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para VIPER38LDTR — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | VIPER38LD | VIPER38HD | VIPER37LD | VIPER28LD |
|---|---|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| Package | NSOIC-16 (16-SO) | NSOIC-16 - same | NSOIC-16 - same | NSOIC-16 - same | NSOIC-16 - same |
| Drain Breakdown Voltage | 800 V | 800 V | 800 V | 800 V | 800 V |
| Switching Frequency | 60 kHz | 60 kHz | 60 kHz | 60 kHz | 60 kHz |
| Output Power (typical) | 1.5 W | 1.5 W | 5 W | 1.0 W | 0.5 W |
| Topology | Offline Flyback | Offline Flyback | Offline Flyback | Offline Flyback | Offline Flyback |
| Light-Load Operation | Burst mode | Burst mode | Burst mode | Burst mode | Burst mode |
| Packaging Media | Tape & Reel | Tube / Tray | Tape & Reel | Tape & Reel | Tape & Reel |
Principais diferenciais
- Tape-and-reel packaging optimized for high-volume SMT (vs VIPER38LD)
- Higher output power headroom than VIPER37 (vs VIPER37LD)
- Pin-compatibility with the wider VIPerPlus family (vs VIPER28LD)
- ST's avalanche-rugged monolithic integration eliminates external clamps (vs Discrete flyback solutions)
Notas de projeto
Estimate: at VIN = 230 VAC rectified (~325 VDC), VOUT = 5 V, IOUT = 0.3 A, the VIPER38LDTR dissipates roughly (325 VDC minus 5 V) times 0.3 A plus primary-side losses, about 1.0-1.2 W in the MOSFET under full load. At 230 VAC input this is well within the 1.5 W envelope, but at 85 VAC (low-line) the peak current is higher and RDS-on losses increase; ensure transformer primary inductance is sized so that the device stays at or above the 60 kHz nominal switching frequency under all line conditions.
Estimated: the NSOIC-16 package has a theta_JA of approximately 80 C/W on 1 oz copper 1 in² 2-layer FR4. At 1.2 W dissipation in a 70 C ambient enclosure, junction temperature rises 96 C above ambient, putting TJ near 166 C - above the 150 C abs max. Add thermal relief copper pour under pins 1 and 16 (DRAIN tabs) and design for at least 1 in² 1 oz to keep TJ below 110 C in fielded white-goods environments.
Route the high-voltage drain loop on the top side of the PCB with minimum loop area. Keep the CS (current-sense) trace short and away from switching nodes. Place the VCC decoupling capacitor and the TOFF capacitor as close as possible to the IC, and add a 10 nF Y-capacitor across the input to reduce common-mode EMI. Per IPC-2221 spacing rules, maintain 6.4 mm clearance between drain traces and secondary-side traces for universal mains isolation.
The fixed 60 kHz oscillator emits a strong fundamental tone at harmonics; pair with a Y-capacitor from primary to secondary ground (typically 2.2 nF X1/Y1-rated) and a snubber across the primary winding (1 nF + 10 kohm) to soften leakage-spike edges. A common-mode choke on the AC input is normally required to meet EN 55022 Class B; tune the Pi-filter L-C values using the STMicroelectronics EMI calculation spreadsheet that ships with the datasheet reference design.
Do not operate the VIPER38LDTR beyond 800 V across drain-to-source - even brief over-voltage from line surges may cause avalanche breakdown that exceeds the MOSFET's E_AS rating. Always include an MOV across the AC input for surge protection and verify that the reflected voltage plus the leakage spike stays below 720 V at maximum line. Also, do not populate the NC pins - they are reserved by ST for future variants and any routing under them may short adjacent nets in the next tape-and-reel lot.
Informações de conformidade
RoHS and REACH compliance confirmed via ST product page; AEC-Q100 not applicable for non-automotive industrial variants; conflict-minerals declaration per STMicroelectronics public statement. Halogen-free status not explicitly listed in the verified web data.
