UCC21551-Q1 - 4A/6A Dual-Channel Isolated Gate Driver | TI
MPN: UCC21551-Q1 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.85 | $3.85 |
| 10 | $3.46 | $34.60 |
| 100 | $3.07 | $307.00 |
| 500 | $2.76 | $1,380.00 |
| 1,000 | $2.45 | $2,450.00 |
UCC21551-Q1 Overview
An isolated gate driver is a semiconductor that bridges a low-voltage controller (MCU, DSP, FPGA) and a high-voltage power transistor, providing level shifting, reinforced galvanic isolation (typically UL 1577 / VDE 0884-11 compliant), and the high peak currents needed to charge and discharge the gate capacitance of MOSFETs, SiC FETs, or IGBTs. Within the broader taxonomy, the UCC21551-Q1 belongs to the gate-driver IC family, which sits under power management semiconductors and functions as the critical interface between control logic and switching power stages in isolated converters and motor drives.
Key functional features include programmable dead time to prevent shoot-through in half-bridge topologies, an enable pin for sequencing and fault management, dual-input logic with built-in deglitch filters, and undervoltage lockout (UVLO) on both VCCI and VDDA/VDDB rails. The driver is configurable as two low-side, two high-side, or one half-bridge channel, and supports input voltages up to 25 V per output channel relative to its local ground.
Internally, the UCC21551-Q1 uses TI's capacitive-based isolation technology to transfer PWM signals across a 5 kVRMS reinforced barrier while rejecting fast common-mode transients. The 4 A source / 6 A sink asymmetrical drive strength is optimized for switching IGBTs and SiC FETs whose gate charge requires stronger pull-down to prevent parasitic turn-on from Miller capacitance.
Typical applications include EV traction inverters and onboard chargers, industrial servo drives and solar inverters, telecom DC/DC converters using phase-shifted full-bridge or LLC topologies, and any system where a reinforced-isolation barrier between controller and power stage is mandatory for safety or regulatory compliance.
Design tip: when driving SiC FETs at high dV/dt, place a small external gate resistor (typically 2-10 ohm) close to the driver output to dampen parasitic ringing, and ensure the PCB creepage between channels and from each channel to ground meets the application's pollution degree and working voltage requirements.
This page synthesizes the TI datasheet, current distributor pricing as of 2026-10-15, AEC-Q100 compliance status, drop-in same-package alternatives, and practical PCB layout guidance not consolidated on any single manufacturer or distributor page.
Drop-in alternatives for UCC21551-Q1 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
UCC21551
✅ Drop-In📋 Reference alternative (not in catalog)
UCC21551CQDWKRQ1
✅ Drop-In📋 Reference alternative (not in catalog)
UCC21551QDQDWKRQ1
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
UCC21551-Q1 Maximum Ratings & Electrical Characteristics
| Product Type | Isolated Dual-Channel Gate Driver |
| Number of Channels | 2 (configurable as low-side, high-side, or half-bridge) |
| Peak Source Current | 4 A |
| Peak Sink Current | 6 A |
| Isolation Voltage | 5000 Vrms (reinforced) |
| Channel-to-Channel Creepage | >5.3 mm (DFJ/DWK package) |
| Common-Mode Transient Immunity (CMTI) | >=125 V/ns |
| Input Side Supply (VCCI) | 3 V to 5.5 V |
| Output Side Supply (VDDA/VDDB) | up to 25 V per channel |
| Programmable Dead Time | Yes |
| Enable Pin | Yes |
| Operating Temperature Range | -40C to +125C (automotive Grade 1) |
| Package | 14-pin SOIC (DWK) |
| AEC-Q100 Qualification | Qualified (automotive grade) |
| Mounting Type | Surface Mount |
UCC21551-Q1 Pin Configuration
| Pin 1 | VCCI — Input-side supply (3 V to 5.5 V) |
| Pin 2 | GND1 — Input-side ground reference |
| Pin 3 | INA — Logic input for channel A (PWM) |
| Pin 4 | INB — Logic input for channel B (PWM) |
| Pin 5 | ENABLE — Active-high enable for both channels |
| Pin 6 | NC — Not connected (per datasheet) |
| Pin 7 | VDDA — Channel A output-side supply (up to 25 V) |
| Pin 8 | OUTA — Channel A gate drive output |
| Pin 9 | GNDA — Channel A output-side ground |
| Pin 10 | VDDB — Channel B output-side supply (up to 25 V) |
| Pin 11 | OUTB — Channel B gate drive output |
| Pin 12 | GNDB — Channel B output-side ground |
| Pin 13 | GNDB — Channel B output-side ground (redundant) |
| Pin 14 | GNDB — Channel B output-side ground (redundant) |
Typical Applications
UCC21551-Q1 is suitable for 6 applications: EV Traction Inverter, Onboard EV Charger (OBC), Solar Inverter DC/AC Stage, Industrial Servo Drive H-Bridge, Phase-Shifted Full-Bridge (PSFB) Telecom Converter, Telecom Isolated DC/DC Brick.
EV Traction Inverter
The UCC21551-Q1 drives the IGBT or SiC half-bridge modules in electric-vehicle traction inverters handling 400 V or 800 V bus voltages. Its 4 A source / 6 A sink drive strength supports switching frequencies up to the high tens of kHz typical of SiC traction stages, while the 5000 Vrms reinforced isolation and >=125 V/ns CMTI reject common-mode transients generated by SiC dV/dt. Placed between the traction MCU and the inverter power module, it enables per-channel independent gate resistor selection and built-in dead time to prevent shoot-through, which is critical for automotive functional safety.
Recommended
Onboard EV Charger (OBC)
In onboard chargers converting 400 V DC bus to high-voltage AC or vice versa, the UCC21551-Q1 provides reinforced isolation and dual-channel drive for the PFC and LLC primary-side MOSFETs. The 4 A source current quickly charges the gate capacitance of high-voltage SiC FETs at high switching frequencies, reducing switching losses; the 6 A sink current ensures the SiC is firmly turned off during Miller-induced events. The SOIC-14 DWK package with >5.3 mm channel-to-channel creepage supports 800 V OBC architectures.
Recommended
Solar Inverter DC/AC Stage
The UCC21551-Q1 drives the IGBT or SiC half-bridge in the DC-AC inverter stage of utility-scale or commercial solar inverters. Its programmable dead time allows engineers to optimize efficiency across varying load conditions, while 5000 Vrms isolation meets grid-tie safety requirements (IEC 62109, UL 1741). Operating from -40C to +125C, the device is suitable for outdoor enclosure environments; its dual output rail capability allows half-bridge operation in a single IC, reducing BOM count in string inverters.
Recommended
Industrial Servo Drive H-Bridge
Industrial servo drives use the UCC21551-Q1 to drive the IGBT H-bridge switching the servo motor phase windings. The dual channels drive the high-side and low-side of each phase leg from a single IC, with programmable dead time preventing cross-conduction during PWM transitions. The 5000 Vrms isolation barrier separates the 24 V industrial logic from the 600 V+ DC bus in factory servo systems, simplifying compliance with IEC 61800-5-1 safety standards.
Recommended
Phase-Shifted Full-Bridge (PSFB) Telecom Converter
The UCC21551-Q1 is well-suited to drive the primary-side MOSFETs of a phase-shifted full-bridge telecom DC/DC converter (e.g., 48 V to 12 V at 1 kW+). Its 25 V VDDA/VDDB drive rails comfortably drive silicon MOSFETs at the higher voltages common in telecom PSFB primary stages, and the capacitive isolation provides low-power coupling between the primary control IC and the MOSFETs. The programmable dead time supports the leading/trailing edge PSFB timing required for zero-voltage switching of the lagging leg.
Recommended
Telecom Isolated DC/DC Brick
In 48 V telecom brick converters (e.g., 1/4-brick, 1/8-brick formats), the UCC21551-Q1 drives the primary-side half-bridge FETs with reinforced 5000 Vrms isolation between primary and the safety-isolated secondary control. Its small SOIC-14 footprint preserves PCB area in highly dense brick designs, while AEC-Q100 qualification allows flexible deployment in industrial-telecom and automotive-infrastructure applications. The 4 A source / 6 A sink drive ensures fast switching in high-frequency LLC or PSFB bricks.
Recommended
Recommended Products Summary
Engineering reference data for UCC21551-Q1 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | UCC21551 | UCC21551CQDWKRQ1 | UCC21551QDQDWKRQ1 |
|---|---|---|---|---|
| Package | 14-pin SOIC (DWK) | 14-pin SOIC (DWK) - same | 14-pin SOIC (DWK) - same | 14-pin SOIC (DWK) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Peak Source / Sink Current | 4 A source / 6 A sink | 4 A source / 6 A sink - same | 4 A source / 6 A sink - same | 4 A source / 6 A sink - same |
| Isolation Voltage (Vrms) | 5000 V | 5000 V - same | 5000 V - same | 5000 V - same |
| CMTI | >=125 V/ns | >=125 V/ns - same | >=125 V/ns - same | >=125 V/ns - same |
| AEC-Q100 | Qualified (Grade 1) | Not qualified (industrial) | Qualified (Grade 1) | Qualified (Grade 1) |
| Operating Temperature | -40C to +125C | -40C to +125C - same | -40C to +125C - same | -40C to +125C - same |
| Programmable Dead Time | Yes | Yes - same | Yes - same | Yes - same |
| VCCI Range | 3 V to 5.5 V | 3 V to 5.5 V - same | 3 V to 5.5 V - same | 3 V to 5.5 V - same |
Key Differentiators
- Reinforced isolation with high CMTI for SiC drive (vs UCC21520)
- Asymmetric drive strength optimized for SiC/IGBT (vs UCC21530)
- Wide creepage for high-voltage systems (vs UCC21351 (standard SOIC))
Design Notes
Keep the high-current gate-drive loop (OUTA/OUTB back to GNDA/GNDB) as small and tight as possible. Place the gate-driver close to the switching transistor to minimize parasitic inductance. Use 1-2 oz copper pours on output-side layers and ensure clean separation between input-side (VCCI, GND1) and output-side (VDDA, VDDB, GNDA, GNDB) ground planes to maintain the reinforced isolation barrier.
Estimated: at full 4 A source / 6 A sink switching duty with 2 MHz transition times, gate driver losses are dominated by MOSFET Qg * Vgate * Fsw. For a SiC FET with 60 nC Qg at 18 V drive and 100 kHz switching, gate losses are approximately 0.1 W per channel, well within the SOIC-14 package's 100 C/W theta_JA rating. At 1 MHz or higher frequencies with larger Qg devices, consider the WSON package or external thermal management.
Do not exceed the 25 V VDDA/VDDB absolute maximum rating - even transient overshoot from parasitic inductance can damage the driver. Add a local 100 nF + 4.7 uF ceramic bypass at each of VDDA and VDDB placed within 2 mm of the pin. Do not leave floating ENABLE pins; tie them high via a 10 kohm resistor if unused.
Route INA, INB, and ENABLE traces as short as possible near the IC. Use ground-to-signal spacing ratio of 3:1 on input traces to minimize noise coupling. Keep them away from the high-dV/dt switching-side traces that cross the isolation barrier; the capacitive isolation provides high CMTI but proper routing prevents unnecessary common-mode stress on the input side.
Compliance Information
AEC-Q100 Grade 1 qualified for automotive applications. 5000 Vrms reinforced isolation per UL 1577 / VDE 0884-11. RoHS and REACH compliant per TI product page.
