UCC21521 - 4A/6A 5.7kVrms Isolated Gate Driver | TI
MPN: UCC21521DWR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.65 | $3.65 |
| 10 | $3.28 | $32.80 |
| 100 | $2.86 | $286.00 |
| 500 | $2.48 | $1,240.00 |
| 1,000 | $2.15 | $2,150.00 |
Drop-in alternatives for UCC21521DWR — 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:
UCC21521Q-Q1
✅ Drop-In✓ In Stock
$1 / Unit
View Datasheet →UCC21520Q-Q1
✅ Drop-In✓ In Stock
$2.85 / Unit
View Datasheet →UCC21540QDWKRQ1
✅ Drop-In✓ In Stock
$2.21 / Unit
View Datasheet →UCC21550Q-Q1
✅ Drop-In✓ In Stock
$2.1 / Unit
View Datasheet →UCC21530Q-Q1
✅ Drop-In✓ In Stock
$2.1 / Unit
View Datasheet →NCP51520
✅ Drop-In📋 Reference alternative (not in catalog)
UCC21521DWR Maximum Ratings & Electrical Characteristics
| Channel Count | 2 |
| Peak Source Current | 4 A |
| Peak Sink Current | 6 A |
| Isolation Rating | 5700 Vrms |
| CMTI | 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 |
| Max Switching Frequency | 5 MHz |
| Isolation Technology | Capacitive coupling |
| Input Threshold | TTL and CMOS compatible (3.3 V logic) |
| Enable / Disable Pin | Yes (DIS) |
| Operating Temperature | -40C to +125C |
| Package | SOIC-16 (DW) |
| Mounting Type | Surface Mount |
| Configurations | Dual low-side, dual high-side, or half-bridge |
| RoHS Status | Compliant |
UCC21521DWR Pin Configuration
| Pin 1 | VCCI — Input-side supply voltage |
| Pin 2 | GND — Input-side ground |
| Pin 3 | INA — Input A, TTL/CMOS compatible |
| Pin 4 | NC — No connect |
| Pin 5 | DIS — Disable input (enable control) |
| Pin 6 | NC — No connect |
| Pin 7 | NC — No connect |
| Pin 8 | INB — Input B, TTL/CMOS compatible |
| Pin 9 | NC — No connect |
| Pin 10 | GNDB — Output B ground reference |
| Pin 11 | OUTB — Gate drive output B (6-A sink) |
| Pin 12 | VDDB — Output B supply |
| Pin 13 | VDDB — Output B supply |
| Pin 14 | VDDB — Output B supply |
| Pin 15 | OUTA — Gate drive output A (6-A sink) |
| Pin 16 | VDDA — Output A supply |
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: Industrial Motor Drives, Solar Inverters, EV Onboard Chargers, Isolated DC-DC Converters, SiC MOSFET Half-Bridge Power Stages, Battery Management and Test Equipment.
Industrial Motor Drives
In three-phase inverters for industrial motor drives, the UCC21521 drives the low-side and high-side IGBT or SiC MOSFET gates of each phase leg with 4-A source and 6-A sink currents, enabling switching frequencies well into the tens of kilohertz. Its 19-ns propagation delay and 5-ns delay matching keep PWM channels synchronized, reducing torque ripple and dead-time losses. The 5.7-kVrms reinforced barrier with 100-V/ns CMTI withstands dv/dt transients at the switch node, while the DIS pin supports safe fault shutdown of all gates simultaneously.
Recommended
Solar Inverters
Grid-tied solar inverters combine an MPPT DC-DC boost stage with a DC-AC H-bridge, both requiring isolated gate drive from a grounded controller. The UCC21521's 5.7-kVrms reinforced isolation provides the galvanic barrier between the DSP PWM outputs and the floating power-switch gates, while 100-V/ns CMTI keeps the outputs stable against boost-stage dv/dt. Its universal architecture supports dual low-side boost configurations and half-bridge arrangements, and the 4-A/6-A drive quickly charges large gate capacitances to minimize switching loss and maximize conversion efficiency.
Recommended
EV Onboard Chargers
EV onboard chargers use isolated LLC or phase-shifted full-bridge converters where the UCC21521 provides the isolated gate-drive barrier for the primary-side power switches. Its 5.7-kVrms rating satisfies reinforced-isolation requirements between the high-voltage battery bus and low-voltage control electronics, and the 100-V/ns CMTI handles hard-switching transients. With a -40C to +125C operating range and the automotive-qualified UCC21521Q-Q1 variant available, the driver meets underhood and harsh-environment requirements while the DIS pin enables coordinated shutdown during fault conditions.
Recommended
Isolated DC-DC Converters
In high-density isolated DC-DC converters such as full-bridge and push-pull topologies, the UCC21521 drives both primary-side switches with tight 5-ns channel matching, which maintains flux balance in the transformer and prevents saturation. The 4-A/6-A drive strength supports fast edge rates up to 5 MHz, allowing small magnetics and high power density. Capacitive coupling delivers the isolation barrier without optocoupler aging effects, ensuring consistent 19-ns delay over lifetime, while TTL/CMOS-compatible inputs interface directly with 3.3-V digital controllers.
Recommended
SiC MOSFET Half-Bridge Power Stages
SiC MOSFETs switch with very high dv/dt, and the UCC21521 is explicitly designed for this environment: its minimum 100-V/ns CMTI prevents dv/dt-induced false turn-on, and the 6-A sink current rapidly discharges gate charge to hold the SiC switch firmly off during opposite-switch transients. Programmable dead time via the interlock logic prevents shoot-through in half-bridge legs, and 19-ns delay plus 6-ns maximum pulse-width distortion keeps high-frequency (hundreds of kHz to MHz) PWM accurate, maximizing the efficiency benefits of SiC technology.
Recommended
Battery Management and Test Equipment
High-voltage battery testers and BMS-adjacent power conversion stages need safe isolated drive of load switches and converter transistors. The UCC21521's 5.7-kVrms isolation protects low-voltage measurement circuitry from the battery bus, while the DIS enable pin allows the test controller to gate off power stages immediately on fault detection. The -40C to +125C range and capacitive-isolation robustness ensure stable timing (19-ns delay, 6-ns PWD) across environmental stress, supporting repeatable, high-accuracy battery cycling and formation equipment.
Recommended
Recommended Products Summary
Engineering reference data for UCC21521DWR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | UCC21521Q-Q1 | UCC21520Q-Q1 | NCP51520 |
|---|---|---|---|---|
| Package | SOIC-16 (DW) | SOIC-16 (DW) - same | SOIC-16 (DW) - same | SOIC-16 - similar, verify footprint |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | onsemi |
| Peak Source Current | 4 A | 4 A | 4 A | [DATA_NEEDED] |
| Peak Sink Current | 6 A | 6 A | 6 A | [DATA_NEEDED] |
| Isolation Rating | 5.7 kVrms | 5.7 kVrms | 5.7 kVrms | [DATA_NEEDED] |
| CMTI | 100 V/ns min | 100 V/ns min | 100 V/ns min | [DATA_NEEDED] |
| Enable / DIS Pin | Yes | Yes | No (pin logic differs) | [DATA_NEEDED] |
| AEC-Q100 Qualification | No (standard grade) | Yes (Q1) | Yes (Q1) | No |
| Operating Temperature | -40C to +125C | -40C to +125C | -40C to +125C | [DATA_NEEDED] |
Key Differentiators
- DIS enable pin for sequencing and fault shutdown (vs UCC21520Q-Q1)
- Reinforced 5.7-kVrms barrier with >=100-V/ns CMTI (vs NCP51520)
- Universal architecture (dual low-side, dual high-side, half-bridge) (vs UCC21540QDWKRQ1)
Design Notes
Place 100-nF to 1-uF decoupling capacitors within 2 mm of VCCI/GND and VDDA/VDDB to their respective grounds. Keep the gate loop (VDD-OUT-gate-source return) as short and small as possible; excessive parasitic inductance causes gate ringing, overshoot, and dv/dt-induced turn-on. Per the TI datasheet typical application, add an external gate resistor to control switching speed and damp ringing.
Unused input pins must not float: tie INA and INB to GND when a channel is not driven, and pull DIS to the inactive level. Floating inputs near thresholds can cause output chatter under high-dv/dt. Use short, ground-referenced traces from the controller to INA/INB, and add a small RC filter if the PWM source is noisy or routed near switching nodes.
When substituting UCC21520 or competitor parts, verify pin 5 (DIS) logic first - TI E2E forum threads document failures from reversed enable logic between UCC21521 and UCC21541. Also confirm VCCI range compatibility with your controller supply (3.3-V vs 5-V logic) and ensure output supply rails (VDDA/VDDB) respect the datasheet absolute maximum limits for your gate voltage.
Size the VDDA/VDDB supply for the total gate charge: I_avg = Qg x fsw per channel. For example, a 60-nC SiC MOSFET at 500 kHz needs 30 mA average per channel plus margin for the driver quiescent current. Under-supplied rails cause slower switching and reduced 4-A/6-A peak capability, increasing switching losses.
Compliance Information
RoHS compliant per TI product page. AEC-Q100 qualification applies to the UCC21521Q-Q1 variant, not the standard part. Additional compliance details not present in provided data.
