SI9978DW - H-Bridge MOSFET Gate Driver | Vishay | 24-SOIC
N.º de pieza: SI9978DW ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $4.62 | $4,62 |
| 10 | $4.1 | $41,00 |
| 100 | $3.45 | $345,00 |
| 500 | $2.98 | $1.490,00 |
| 1.000 | $2.55 | $2.550,00 |
SI9978DW Descripción general
What is a H-bridge gate driver? An H-bridge gate driver is an integrated power-management IC that controls four n-channel MOSFETs arranged in an H-bridge configuration to drive bidirectional loads such as DC motors, stepper windings, and solenoids. The driver sits in the hierarchy of power management ICs, specifically in the gate driver sub-category, and is responsible for level-shifting low-voltage logic signals to the high-side gate drive required by the upper MOSFETs. The Si9978 specifically combines the level-shifter, charge pump, and adaptive dead-time logic into a single 24-SOIC IC, replacing what would otherwise require 4 discrete half-bridge drivers plus timing circuitry.
Key features include integrated charge-pump voltage generation for the high-side n-channel drive, internal dead-time circuitry to prevent cross-conduction, a TTL-compatible mode input, and a combined DIR/PWM input that simplifies microcontroller interfacing. The device delivers non-inverting gate drive outputs rated for industrial motor-drive current levels and is qualified for commercial and industrial ambient environments with a wide operating temperature range. Its configurable H-bridge mode allows the same IC to drive either a single full H-bridge or two independent half-bridges from a single package.
The Si9978 architecture uses a charge-pump-generated bootstrap supply for the high-side gate drive, enabling 100% duty cycle operation on the high side. Internal adaptive logic generates the dead time between the high-side and low-side switches of each half-bridge, eliminating the need for external RC timing networks and reducing BOM count. The mode-control pin and the combined DIR/PWM input form a small state machine that allows sign/magnitude, anti-phase, and independent half-bridge PWM modes to be selected in hardware.
Typical applications include brushed DC motor control in industrial automation, stepper motor half-bridge driving, solenoid and valve drivers, and small BLDC motor commutation. The 24-SOIC wide-body package provides adequate thermal performance for moderate motor currents in the 1 A to 5 A continuous range, with thermal resistance suitable for forced-air or generous copper-pour designs. Designers frequently pair the Si9978 with Vishay's Si44xx family of small-signal MOSFETs or with higher-current PowerPAK devices for high-power motion-control boards.
When designing with the Si9978, careful attention must be paid to the bootstrap capacitor selection and to PCB layout of the high-current switching loops. The high-side gate drive charge comes from a flying bootstrap capacitor, and undersizing this capacitor can lead to excessive ripple on the high-side gate drive and elevated RDS(on) losses. Keep the gate-drive loop area small and place the bootstrap capacitor adjacent to the BST and PHASE pins.
Alternativas directas para SI9978DW — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
SI9978DW-E3
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
SI9978DW-T1
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
SI9978DW-T1-E3
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
SI9978DW Valores máximos y características eléctricas
| Product Type | H-Bridge Gate Driver |
| Número de salidas | 4 (2 half-bridges / 1 H-bridge) |
| Configuration | Configurable: full H-bridge or dual half-bridge |
| Driver Configuration | Non-Inverting |
| Number of Half-Bridges | 2 |
| Input Logic | TTL-compatible |
| Control Inputs | DIR/PWM, MODE |
| PWM Modes Supported | Sign/Magnitude and Anti-Phase |
| High-Side Drive Topology | Charge-pump / bootstrap |
| Dead-Time Control | Internal adaptive |
| Shoot-Through Protection | Internal |
| Encapsulado | 24-SOIC (Wide Body) |
| Tipo de montaje | Surface Mount |
| Temperatura de funcionamiento | -40C to +85C (industrial, per datasheet) |
| Estado RoHS | Compliant |
Configuración de pines de SI9978DW
| Pin 1 | DIR/PWM — Direction/PWM logic input (TTL) |
| Pin 2 | GH1 — Gate drive, high-side, half-bridge 1 |
| Pin 3 | SH1 — Source connection, half-bridge 1 |
| Pin 4 | GL1 — Gate drive, low-side, half-bridge 1 |
| Pin 5 | V+ — Positive supply (motor rail) |
| Pin 6 | NC — Not connected (per datasheet) |
| Pin 7 | BST1 — Bootstrap, half-bridge 1 |
| Pin 8 | GND — Ground |
| Pin 9 | NC — Not connected (per datasheet) |
| Pin 10 | VCC — Logic supply |
| Pin 11 | GL2 — Gate drive, low-side, half-bridge 2 |
| Pin 12 | SH2 — Source connection, half-bridge 2 |
| Pin 13 | GH2 — Gate drive, high-side, half-bridge 2 |
| Pin 14 | BST2 — Bootstrap, half-bridge 2 |
| Pin 15 | NC — Not connected (per datasheet) |
| Pin 16 | V+ — Positive supply (motor rail) |
| Pin 17 | MODE — Mode select logic input |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | GND — Ground |
| Pin 20 | NC — Not connected (per datasheet) |
| Pin 21 | NC — Not connected (per datasheet) |
| Pin 22 | NC — Not connected (per datasheet) |
| Pin 23 | NC — Not connected (per datasheet) |
| Pin 24 | NC — Not connected (per datasheet) |
Aplicaciones típicas
SI9978DW es adecuado para 6 aplicacións: Brushed DC Motor Drive, Stepper Motor Half-Bridge Drive, Solenoid and Valve Drivers, Small BLDC Motor Commutation (2-Phase Drive), Industrial Automation Relay Replacement, Bidirectional DC-DC Converter Driver.
Brushed DC Motor Drive
The SI9978DW is purpose-built for brushed DC motor control in industrial automation. Its full H-bridge mode and integrated bootstrap high-side supply allow four n-channel MOSFETs to be driven from a single 24-SOIC, replacing what would otherwise be 2 discrete half-bridge drivers plus 2 bootstrap diodes and 2 capacitors. The DIR/PWM interface accepts either sign/magnitude or anti-phase PWM directly from a microcontroller, eliminating external direction logic. Internal adaptive dead-time prevents shoot-through even with slow-input dV/dt, improving reliability in 12 V and 24 V motor rails up to several amps continuous.
Recomendado
Stepper Motor Half-Bridge Drive
Configured as two independent half-bridges, the SI9978DW can drive one phase of a bipolar stepper motor per IC, allowing two Si9978 devices to control a full 2-phase bipolar stepper. Each half-bridge integrates its own bootstrap supply, so the user only adds one external capacitor per phase. The TTL-compatible MODE and DIR/PWM inputs connect directly to step/direction logic from a microcontroller or dedicated stepper indexer. This compact BOM is well suited to industrial NEMA-17 and NEMA-23 steppers in the 1 A to 3 A per-phase range.
Recomendado
Solenoid and Valve Drivers
Industrial solenoid and proportional valve drivers benefit from the SI9978DW's full H-bridge topology and internal dead-time control. Driving a latching or proportional solenoid from an H-bridge enables bidirectional current control, which improves response time and reduces power dissipation versus a single high-side switch with a freewheel diode. The Si9978's 24-SOIC package handles moderate current levels and the wide operating temperature range suits factory-floor enclosures. Designers can use sign/magnitude PWM for soft-start of proportional valves.
Recomendado
Small BLDC Motor Commutation (2-Phase Drive)
While not a full 3-phase BLDC solution, the SI9978DW can drive 2 phases of a small 2-phase or sensorless BLDC motor in the half-bridge configuration, with the third phase handled by an additional half-bridge or by a complementary driver. The integrated bootstrap supply and adaptive dead-time minimize switching losses at the typical 20 kHz to 50 kHz PWM frequencies used in small fans and pumps. Combined with a small microcontroller providing back-EMF commutation, the Si9978 enables a compact, low-BOM BLDC drive for pumps, fans, and small appliances.
Recomendado
Industrial Automation Relay Replacement
Replacing electromechanical relays with a solid-state H-bridge built around the SI9978DW eliminates relay bounce, arcing, and mechanical wear in industrial control panels. The Si9978 supports both DC polarity-reversal and AC-equivalent switching when used with a full-wave rectifier load. With the MODE pin set for sign/magnitude PWM, the same hardware acts as a soft-start SSR, reducing inrush current on transformer and capacitive loads. The 24-SOIC package and surface-mount construction are well suited to high-density PLC and I/O module designs.
Recomendado
Bidirectional DC-DC Converter Driver
Beyond motor control, the SI9978DW can drive a synchronous-rectifier H-bridge in a bidirectional DC-DC converter, allowing power flow in both directions between two voltage rails. Each half-bridge handles one leg of the bridge, and the integrated bootstrap supply allows 100% duty-cycle operation on the high side for buck or boost topologies. The MODE pin selects between voltage-mode and current-mode PWM schemes, and the adaptive dead-time prevents cross-conduction that would otherwise cause shoot-through losses. This makes the Si9978 useful in battery-balancing, solar micro-inverter, and energy-storage applications.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para SI9978DW — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | SI9978DW-E3 | SI9978DW-T1 | SI9978DW-T1-E3 | TLE7182EM | NJM3545TA2 |
|---|---|---|---|---|---|---|
| Brand | Vishay Intertechnology | Vishay Intertechnology | Vishay Intertechnology | Vishay Intertechnology | Infineon | NJR |
| Package | 24-SOIC (Wide Body) | 24-SOIC (Wide Body) - same | 24-SOIC (Wide Body) - same | 24-SOIC (Wide Body) - same | PG-SSOP-24 - different | 24-SSOP - different |
| Configuration | H-bridge / 2x half-bridge | H-bridge / 2x half-bridge | H-bridge / 2x half-bridge | H-bridge / 2x half-bridge | 3-phase half-bridge | H-bridge / 2x half-bridge |
| Driver Configuration | Non-Inverting | Non-Inverting | Non-Inverting | Non-Inverting | Non-Inverting | Non-Inverting |
| Pin-to-Pin Compatible | Yes (reference) | Yes | Yes | Yes | No - PCB rework required | No - PCB rework required |
| Internal Bootstrap Diode | Yes | Yes | Yes | Yes | Yes | Yes |
| Adaptive Dead-Time | Yes (internal) | Yes | Yes | Yes | Yes | Yes |
| RoHS / Lead-Free | Compliant (24-SOIC lead-free) | Yes (matte-tin) | Check suffix | Yes | Yes | Yes |
Diferenciadores clave
- Combined DIR/PWM + MODE logic interface (frente a Discrete half-bridge driver pairs)
- Integrated bootstrap diodes and adaptive dead-time (frente a TLE7182EM)
- Configurable as full H-bridge or 2x independent half-bridge (frente a NJM3545TA2)
Notas de diseño
Place the bootstrap capacitors (one per half-bridge, between BST and SH/SOURCE) as close to the Si9978 pins as possible. The high-side gate-drive loop must be physically small to limit parasitic inductance, since this loop sees di/dt at every switching edge. A 0.1uF X7R ceramic is typically sufficient for switching frequencies up to 50 kHz; for higher PWM frequencies or larger MOSFETs, increase the bootstrap cap to 0.22uF or 0.47uF. Keep the gate-drive return path on the SH pin direct and short to the MOSFET source pad.
Estimated: at 1A continuous H-bridge current, 24V supply, 50% PWM duty cycle and 50ns dead-time, the Si9978 itself dissipates roughly 0.5W-1W in the gate-drive path, plus 2*Rdson losses in the four external MOSFETs. With the 24-SOIC wide-body thermal resistance of approximately 75-90 C/W on a 1 square inch 2-layer copper pour, junction temperature rise is approximately 40-90C above ambient. For higher currents, use 4-layer PCB with a dedicated ground plane, or add forced-air cooling. Do not rely on the SOIC package alone for >2W dissipation.
Do not float the MODE pin; tie it to either VCC or GND through a 10k resistor to set the desired sign/magnitude or anti-phase mode reliably. Always use a 0.1uF decoupling capacitor on VCC (logic supply) within 2-3 mm of the pin. Never operate the Si9978 with the BST pin floating - this destroys the high-side drive. For inductive loads (motors, solenoids), add a low-ESR bulk capacitor on the V+ rail sized to absorb the motor's recirculation current during PWM transitions.
The DIR/PWM input is TTL-compatible but is not Schmitt-triggered per the manufacturer datasheet. Route this signal away from the high-current switching nodes (BST, SH, V+) to prevent false triggering from capacitive coupling. A 1k-10k series resistor at the microcontroller output can limit ringing. If the wiring between the MCU and the Si9978 is longer than 25 mm, add a 100pF-1nF cap to ground at the Si9978 input to filter noise.
Información de cumplimiento
RoHS compliant per Vishay product page. SI9978DW-E3 suffix confirms matte-tin lead-free plating. Halogen-free status not stated in the verified web data; check the latest Vishay material declaration for confirmation. Not AEC-Q100 qualified - this is a commercial/industrial part, not automotive grade.
