UCC21521 - 4A/6A 5.7kVrms Isolated Gate Driver | Texas Instruments
MPN: UCC21521DWR β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.2 | $3.20 |
| 10 | $2.88 | $28.80 |
| 100 | $2.45 | $245.00 |
| 500 | $2.1 | $1,050.00 |
| 1,000 | $1.85 | $1,850.00 |
Drop-in alternatives for UCC21521DWR β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
UCC21520
β Drop-Inβ In Stock
$1.55 / Unit
View Datasheet βUCC21521Q-Q1
β Drop-Inβ In Stock
$1 / Unit
View Datasheet βUCC21520Q-Q1
β Drop-Inβ In Stock
$2.85 / Unit
View Datasheet βUCC21521A
β Drop-Inπ Reference alternative (not in catalog)
UCC21541
β‘ Same Packageπ Reference alternative (not in catalog)
UCC21540
β‘ Same Packageβ In Stock
$1.85 / Unit
View Datasheet βUCC21521DWR Maximum Ratings & Electrical Characteristics
| Channels | 2 (dual low-side, dual high-side, or half-bridge) |
| Peak Source Current | 4 A |
| Peak Sink Current | 6 A |
| Isolation Rating | 5.7 kVRMS (reinforced) |
| Isolation Technology | Capacitive coupling |
| CMTI (Common-Mode Transient Immunity) | 100 V/ns (minimum) |
| Propagation Delay | 19 ns (typical) |
| Delay Matching | 5 ns (maximum) |
| Pulse-Width Distortion | 6 ns (maximum) |
| Minimum Pulse Width | 10 ns |
| Maximum Switching Frequency | 5 MHz |
| Input Threshold | TTL/CMOS compatible, 3.3-V MCU friendly |
| Operating Temperature | -40C to +125C |
| Package | SOIC-16 (DW) |
| Mounting Type | Surface Mount |
| Enable Pin | Yes |
| Target Devices | MOSFETs, IGBTs, SiC MOSFETs |
| RoHS Status | [DATA_NEEDED: RoHS status] |
UCC21521DWR Pin Configuration
| Pin 1 | GND β Input-side ground reference |
| Pin 2 | INA β Input channel A (TTL/CMOS compatible) |
| Pin 3 | INB β Input channel B (TTL/CMOS compatible) |
| Pin 4 | EN β Enable input for both channels |
| Pin 5 | DT β Dead-time programming pin [DATA_NEEDED: confirm exact pin function per datasheet] |
| Pin 8 | VCCI β Input-side supply voltage |
| Pin 6 | NC β [DATA_NEEDED: confirm per datasheet] |
| Pin 9 | VDDA β Channel A output driver supply |
| Pin 12 | OUTA β Channel A gate-drive output |
| Pin 13 | VDDB β Channel B output driver supply |
| Pin 16 | OUTB β Channel B gate-drive output |
| Pin 11 | GNDA β Channel A driver ground return |
| Pin 14 | GNDB β Channel B driver ground return |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
UCC21521DWR is suitable for 6 applications: Solar Inverters, Motor Drives, EV Chargers and Onboard Power, Industrial Power Supplies, SiC/GaN Wide-Bandgap Power Stages, Battery Test and Formation Systems.
Solar Inverters
In solar string and micro inverters, the UCC21521 drives the half-bridge power stages switching SiC MOSFETs or IGBTs at 20-100 kHz. Its 5.7-kVRMS reinforced isolation separates the DC high-voltage bus from the controller domain, while 100-V/ns CMTI tolerates the steep switching edges of wide-bandgap devices. The 19-ns propagation delay and 5-ns matching keep dead time tight, improving conversion efficiency, and the EN pin with programmable dead time prevents shoot-through during PWM fault shutdown.
Recommended
Motor Drives
The UCC21521's universal configuration (dual low-side, dual high-side, or half-bridge) makes it well suited to three-phase inverter legs in industrial motor drives. The 5.7-kVRMS isolation barrier protects the MCU from the motor power stage, and 100-V/ns CMTI prevents false triggering from dv/dt at the switch node. 6-A sink current yields fast MOSFET/IGBT turn-off, limiting switching losses in drives up to several kW, while -40C to +125C operation covers industrial ambient conditions.
Recommended
EV Chargers and Onboard Power
In EV onboard chargers (OBC) and DC-DC stages, the UCC21521 drives CLLLC or LLC half-bridge/full-bridge switches with high switching frequency. Its 5-MHz capability and 10-ns minimum pulse width support high-frequency resonant topologies that shrink magnetics, and 5.7-kVRMS reinforced isolation satisfies battery-to-grid safety separation. The automotive UCC21521Q-Q1 variant offers an AEC-Q100 path; 5-ns channel matching preserves resonant waveform symmetry for efficiency.
Recommended
Industrial Power Supplies
Server, telecom, and industrial AC-DC converters use the UCC21521 in PFC and LLC half-bridge stages. The 4-A/6-A drive strength rapidly charges and discharges gate capacitance at high frequency, minimizing switching loss, while the 19-ns propagation delay reduces control-loop latency. The TTL/CMOS-compatible inputs connect directly to 3.3-V PWM controllers, and the enable pin allows orderly shutdown and brownout behavior under fault conditions detected by supervisory circuits.
Recommended
SiC/GaN Wide-Bandgap Power Stages
Wide-bandgap devices switch with dv/dt often exceeding 50 V/ns, and the UCC21521's minimum 100-V/ns CMTI prevents spurious turn-on of the complementary device. The 6-A sink current rapidly pulls SiC gates below their negative-recommended thresholds, improving noise immunity and turn-off speed up to 5-MHz operation. Tight 5-ns matching between channels keeps leg switching symmetric, reducing ripple current in half-bridge links and easing EMI filter design.
Recommended
Battery Test and Formation Systems
Battery cyclers and formation equipment use bidirectional DC-DC legs where the UCC21521's configurable dual-channel architecture supports both low-side and high-side drive. The 5.7-kVRMS barrier isolates the control electronics from series battery stacks, and the enable input supports per-channel safety interlocks. Programmable dead time avoids simultaneous conduction during charge/discharge reversal, protecting MOSFETs at high bus voltages during long test cycles.
Recommended
Recommended Products Summary
Engineering reference data for UCC21521DWR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | UCC21520 | UCC21521Q-Q1 | UCC21541 | UCC21540 |
|---|---|---|---|---|---|
| Package | SOIC-16 (DW) | SOIC-16 (DW) - same | SOIC-16 (DW) - same | SOIC-16 (DW) - same (pin 5 logic differs) | SOIC-16 (DW) - same footprint |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Peak Source Current | 4 A | 4 A | 4 A | 4 A | 2 A |
| Peak Sink Current | 6 A | 4 A | 6 A | 6 A | 4 A |
| Isolation Rating | 5.7 kVRMS | 5.7 kVRMS | 5.7 kVRMS | 5.7 kVRMS | 5.7 kVRMS |
| Propagation Delay | 19 ns typ | [DATA_NEEDED] | 19 ns typ | [DATA_NEEDED] | [DATA_NEEDED] |
| CMTI | 100 V/ns min | 100 V/ns min | 100 V/ns min | 100 V/ns min | 100 V/ns min |
| Automotive Grade | No (standard) | No | Yes (AEC-Q100) | No | No (Q1 variant available) |
| Pin 5 Function | DT / control | Same as UCC21521 | Same as UCC21521 | Reversed logic vs UCC21521 | [DATA_NEEDED] |
Key Differentiators
- Asymmetric 4-A source / 6-A sink drive (vs UCC21520)
- Automotive variant available (vs UCC21521Q-Q1 vs UCC21521A)
- Pin-5 logic consistency (vs UCC21541)
Design Notes
Place a 0.1-uF ceramic capacitor within 2-3 mm of each VDDA and VDDB pin, backed by 10-uF of bulk capacitance for gate-charge energy storage. Keep each gate-drive loop (driver OUT - gate - source - GNDA/GNDB) as small as possible to limit parasitic inductance ringing; vias down to the ground plane directly at the driver ground pins.
Do not blindly substitute the UCC21541: per TI E2E forum thread 1092667, pin 5 has reversed logic between the two devices, which can cause inverted behavior at startup. Also ensure the dead-time setting is greater than the sum of the power switch turn-off and turn-on delays to prevent shoot-through in half-bridge operation.
The 100-V/ns CMTI protects against dv/dt at the switch node, but the input-side VCCI and INA/INB traces should still be routed away from gate-drive and switch-node copper. Use a solid ground plane on the input side and avoid crossing the isolation barrier with signal routing on adjacent layers.
At 5-MHz switching with large MOSFETs, driver internal dissipation is roughly Qg * fsw * VDD per channel. Estimate total power and verify SOIC-16 theta-JA supports it without exceeding 125C junction; for very large Qg loads, reduce VDD or switching frequency.
Compliance Information
Standard UCC21521 is not AEC-Q100 qualified; the UCC21521Q-Q1 variant serves automotive applications. RoHS/REACH status [DATA_NEEDED] from TI product page.
