IR21531DPBF - 600V Half-Bridge Gate Driver, 8-PDIP | Infineon
MPN: IR21531DPBF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.2 | $3.20 |
| 10 | $2.88 | $28.80 |
| 100 | $2.55 | $255.00 |
| 500 | $2.21 | $1,105.00 |
| 1,000 | $1.92 | $1,920.00 |
IR21531DPBF Overview
A half-bridge gate driver is a power-management IC that produces two complementary gate-drive signals (high-side referenced to the switching node and low-side referenced to ground) for a pair of power MOSFETs or IGBTs arranged in a totem-pole half-bridge. Within the broader taxonomy, the IR21531DPBF sits in the gate-driver subcategory of power management ICs, above which are MOSFET/IGBT drivers, then switching power supply controllers. Its built-in oscillator means the half-bridge timing is set by a single external RT/CT pair, eliminating the need for a separate PWM controller.
Key specifications include a 600 V half-bridge rating (allowing direct operation from rectified 230 V AC), typical 0.6 µs internal deadtime, a programmable oscillator, an SD (shutdown) function on the CT pin at 1/6 Vcc, increased undervoltage lockout hysteresis, and matched propagation delays for the high-side and low-side outputs. The exposed GND pin supports the high peak gate currents required to switch MOSFETs in the tens-of-nanoseconds transition region.
The architecture is built on Infineon's high-voltage junction-isolation process, which integrates a 600 V level-shift structure on the same die as the 555-style oscillator. This monolithic integration reduces BOM count versus discrete driver + PWM designs and improves timing symmetry between the high-side and low-side channels, which directly lowers shoot-through risk in the half bridge.
Typical applications include fluorescent and HID electronic ballasts, low-power SMPS half-bridge converters, CCFL backlight inverters for displays, and motor-drive half-bridge stages. The 600 V rating allows direct rectification of 230 V AC without an additional bootstrap-clamp circuit, and the 1/6 Vcc shutdown input provides an easy interface to a fault or timer circuit.
When designing with this part, place a 100 nF (minimum) ceramic bypass capacitor directly on Vcc to keep the internal 15.6 V zener from absorbing fast switching transients, and select RT/CT to give an oscillator frequency well above the audible band (>20 kHz) for ballast applications. The bootstrap diode and capacitor must be sized for the worst-case high-side on-time per switching cycle.
This page synthesizes distributor pricing, parametric drop-in alternatives, and PCB-oriented design notes that complement the manufacturer datasheet rather than repeating its tables.
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Request AlternativesIR21531DPBF Maximum Ratings & Electrical Characteristics
| Product Type | Self-oscillating half-bridge gate driver |
| Topology | Half-bridge (high-side + low-side) |
| High-side Offset Voltage (max) | 600 V |
| Vcc Supply Voltage (max) | 20 V (internally clamped at 15.6 V) |
| Vcc Undervoltage Lockout | Increased hysteresis (per datasheet) |
| Internal Deadtime (typical) | 0.6 µs |
| Deadtime Temperature Coefficient | Low (tightened initial deadtime) |
| Oscillator Type | CMOS 555-equivalent, external RT/CT |
| Shutdown Feature | Yes, on CT pin at 1/6 Vcc |
| Integrated Zener Clamp on Vcc | 15.6 V |
| Startup Behavior | True micropower startup |
| Propagation Delay Matching | Matched high-side / low-side (per datasheet) |
| Package | 8-Pin PDIP (through-hole) |
| Mounting Type | Through-hole (THT) |
| Lead-Free / RoHS | Lead-free (PBF suffix); RoHS compliant |
| MSL Level | Not applicable (through-hole) |
IR21531DPBF Pin Configuration
| Pin 1 | Vcc — Logic supply voltage (internally clamped at 15.6 V via integrated zener) |
| Pin 2 | RT — Timing resistor connection for oscillator (sets charging current with CT) |
| Pin 3 | CT — Timing capacitor / shutdown node (1/6 Vcc SD threshold) |
| Pin 4 | GND — Logic and low-side gate-drive return |
| Pin 5 | LO — Low-side gate-drive output (referenced to GND) |
| Pin 6 | VS — High-side floating supply return / switching node |
| Pin 7 | HO — High-side gate-drive output (referenced to VS) |
| Pin 8 | VB — High-side floating supply (bootstrap to VS) |
Typical Applications
IR21531DPBF is suitable for 6 applications: Fluorescent Electronic Ballast, HID Lamp Ballast (Automotive/Street Lighting), Low-Power SMPS Half-Bridge Converter, CCFL Backlight Inverter, Half-Bridge Motor Drive Stage (Low Power), Electronic Transformer for Low-Voltage Halogen.
Fluorescent Electronic Ballast
The IR21531DPBF is a canonical driver for fluorescent lamp electronic ballasts in both 120 V and 230 V AC mains designs. The 600 V high-side offset rating allows direct rectification of 230 V AC without an additional bootstrap clamp, and the integrated 15.6 V Vcc zener eliminates the external clamp diode/zener that discrete ballast drivers require. Designers program the oscillator above 20 kHz (typically 30-50 kHz) via the RT/CT network to push switching harmonics above the audible band and avoid lamp buzz, while the 0.6 µs deadtime with low temperature coefficient prevents shoot-through between the high-side and low-side MOSFETs that would otherwise stress the half bridge during lamp ignition transients.
Recommended
HID Lamp Ballast (Automotive/Street Lighting)
For high-intensity discharge (HID) lamp ballasts the IR21531DPBF's 600 V rating and micropower startup make it well-suited to the high ignition voltages (typically 4-5 kV via an igniter transformer) and long preheat cycles these lamps require. The 1/6 Vcc shutdown feature on the CT pin lets a supervisory MCU or timer circuit disable the half bridge cleanly when the lamp is removed or the ballast is in fault, while the matched high-side/low-side propagation delays keep the ignition arc stable. The 8-PDIP package also withstands the elevated ambient temperatures inside a sealed luminaire housing better than many SOIC equivalents.
Recommended
Low-Power SMPS Half-Bridge Converter
In low-to-medium power offline SMPS (typically below 200 W) the IR21531DPBF can replace a dedicated PWM controller plus separate half-bridge driver, reducing BOM count on the primary side. Its self-oscillating architecture is favored for simple resonant and quasi-resonant forward converters where closed-loop PWM complexity is not required, and the integrated Vcc clamp protects the auxiliary winding rectifiers during no-load bursts. The 600 V rating covers universal-input 85-265 V AC designs without an extra clamp network, and the micropower startup means the IC draws negligible quiescent current until Vcc reaches the UVLO turn-on threshold.
Recommended
CCFL Backlight Inverter
Cold-cathode fluorescent lamp (CCFL) backlight inverters for industrial LCD panels and early LED-backlit displays used Royer-topology oscillators that map directly onto the IR21531DPBF's 555-style oscillator and half-bridge output stage. The 0.6 µs deadtime prevents the cross-conduction that would otherwise burn the Royer transformer primary winding, while the high-side 600 V rating handles the transformer's reflected voltage during lamp striking. The CT-pin shutdown input also provides a clean interface to a brightness-control or fault-detection MCU that needs to disable the inverter on lamp failure.
Recommended
Half-Bridge Motor Drive Stage (Low Power)
For low-voltage brushless DC (BLDC) motor half-bridge stages and small induction-motor drives, the IR21531DPBF can drive the two switches of a half bridge with complementary gate signals derived from its on-chip oscillator. While it does not provide the commutation logic of a dedicated three-phase driver, it is useful for fixed-frequency or simple variable-frequency half-bridge motion where a single RT/CT pair sets the operating point. The matched high-side/low-side propagation delays limit the shoot-through window and improve EMI versus discrete gate-driver alternatives.
Recommended
Electronic Transformer for Low-Voltage Halogen
Electronic low-voltage halogen transformers rely on a self-oscillating half-bridge topology running at 30-60 kHz to drive a small ferrite transformer from the 230 V AC mains. The IR21531DPBF's 600 V rating, integrated 15.6 V Vcc zener, and programmable RT/CT oscillator fit this topology directly, with the 0.6 µs deadtime preventing the cross-conduction that can cause transformer saturation at high line. Its micropower startup also reduces standby loss, which is becoming important under tightening no-load energy regulations.
Recommended
Recommended Products Summary
Engineering reference data for IR21531DPBF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | IR21531SPBF |
|---|---|---|
| Brand | Infineon | Infineon |
| Package | 8-PDIP (through-hole) | SOIC-8 (SMD) - different footprint |
| High-side Offset Voltage (max) | 600 V | 600 V |
| Oscillator Type | CMOS 555-style (external RT/CT) | CMOS 555-style (external RT/CT) |
| Internal Deadtime (typical) | 0.6 µs | 0.6 µs |
| Vcc Clamp Voltage | 15.6 V (integrated) | 15.6 V (integrated) |
| Shutdown Feature | Yes (1/6 Vcc on CT) | Yes (1/6 Vcc on CT) |
| Mounting Type | Through-hole (THT) | Surface Mount (SMT) |
| Pinout vs IR21531DPBF | - | Pin-compatible logic, but SOIC-8 land pattern |
| Approx. qty-1 Price (USD, 2026-09-14) | ~$3.20 | ~$2.80 |
Key Differentiators
- Integrated 15.6 V Vcc zener clamp (vs Discrete 555 + external half-bridge driver design)
- Tightened initial deadtime with low temperature coefficient (vs Legacy IR2155 / IR2151 drivers)
- True micropower startup (vs Conventional high-Iq startup)
Design Notes
Place a 100 nF (minimum) low-ESR ceramic bypass capacitor directly on the IR21531DPBF Vcc pin (pin 1), within 2-3 mm of the package lead. The integrated 15.6 V zener clamps Vcc but is not designed to absorb the fast switching transients that propagate from the half-bridge node; without local bypassing the Vcc rail can ring above the zener during MOSFET switching edges and trigger premature UVLO. A 10 µF bulk capacitor from Vcc to GND is also recommended to absorb the energy delivered by the bootstrap diode during each high-side on-time.
Keep the high-current switching loop (Vcc -> HO -> high-side MOSFET -> low-side MOSFET -> GND) as small and tight as possible on the PCB, ideally directly under the IC's power pins. The 600 V high-side structure on the IR21531DPBF is sensitive to dV/dt coupling into the floating VB supply; a compact loop reduces radiated EMI and prevents the high-side from spuriously re-triggering due to capacitive coupling from the VS node. The bootstrap capacitor (typically 100 nF-1 µF ceramic from VB to VS) must be placed as close to pins 7 and 8 as layout allows.
Do not operate the IR21531DPBF with Vcc above its internal 15.6 V clamp for sustained periods - the integrated zener is sized for transient protection, not continuous dissipation. If your auxiliary winding can deliver more than ~50 mA continuous to Vcc, add a series resistor to limit current or use an external regulator. Also avoid running the oscillator below ~20 kHz in ballast applications, as the resulting acoustic resonance can shatter the lamp envelope; verify RT/CT against the manufacturer's curve in the datasheet before finalizing the BOM.
Compliance Information
PBF suffix indicates lead-free finish; RoHS status per Infineon product page. AEC-Q100 not applicable for this through-hole ballast driver. Halogen-free status not stated in the available distributor data.
