ISL6731BFBZ - CCM PFC Controller, 14-SOIC | Renesas
MPN: ISL6731BFBZ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.42 | $1.42 |
| 10 | $1.28 | $12.80 |
| 100 | $1.13 | $113.00 |
| 500 | $0.96 | $480.00 |
| 1,000 | $0.82 | $820.00 |
| 2,500 | $0.74 | $1,850.00 |
ISL6731BFBZ Overview
A Power Factor Correction (PFC) controller is a type of switch-mode power supply controller that shapes the input current of an AC-DC converter to follow the line voltage waveform, raising the displacement power factor toward unity and reducing total harmonic distortion (THD) below 10%. PFC sits at the front end of AC-DC converters in Power Management systems, ahead of bulk-energy storage and downstream isolated DC-DC converters. Active PFC topologies such as CCM boost, CRM boost, and interleaved boost all rely on a dedicated controller IC for current shaping and feedback regulation.
Key features include a wide input voltage range supporting universal 85-264 VAC operation (after rectification), cycle-by-cycle overcurrent protection (OCP), over-power limit (OPL), over-temperature protection (OTP), input brownout, output overvoltage protection (OVP), and output undervoltage protection (UVP). The device also provides soft-start, programmable switching frequency, and a sync input enabling synchronization to a downstream converter for reduced EMI.
The ISL6731BFBZ uses a transconductance (gm) error amplifier with an internal 3.3 V reference and a multiplier that combines the rectified AC line voltage with the error-amp output to program the peak inductor current on each switching cycle. This analog current-mode control loop ensures near-unity power factor across the full AC-line cycle, while the soft-start and OVP/UVP comparator train prevent start-up inrush and fault-induced stress.
Typical applications include 80 PLUS-compliant desktop PC and server SMPS, 300 W to 2 kW industrial SMPS, front-end PFC stages for telecom rectifiers, UPS input PFC stages, and e-mobility chargers. The 14-SOIC package, 1.5 A gate drive, and integrated protection suite make it well suited to compact, high-density AC-DC converters in industrial and IT equipment.
When designing with the ISL6731BFBZ, place the current-sense resistor (RCS) on the return-side of the boost inductor for accurate cycle-by-cycle current protection and route the VINS and RTN analog grounds separately. The ISET/SYNC pin sets switching frequency via an external resistor; choose 1% tolerance to keep the frequency within ±5% of nominal.
Drop-in alternatives for ISL6731BFBZ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ISL6731BFBZ (same form factor and footprint) — differing in Package, Protection Features, RoHS Status, Topology.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ISL6731AFBZ
✅ Drop-In📋 Reference alternative (not in catalog)
ISL6731BFBZ-T
✅ Drop-In📋 Reference alternative (not in catalog)
UCC28019ADR
✅ Drop-In✓ In Stock
$0.42 / Unit
View Datasheet →NCP1654
✅ Drop-In📋 Reference alternative (not in catalog)
FAN7930MX
✅ Drop-In📋 Reference alternative (not in catalog)
ISL6731BFBZ Maximum Ratings & Electrical Characteristics
| Topology | Power Factor Correction (PFC), Continuous Conduction Mode (CCM) boost |
| Switching Frequency Range | 56.5 kHz to 70.7 kHz |
| Package | 14-SOIC (Pb-Free, M14.15) |
| Operating Temperature Range | -40 C to +125 C |
| Gate Driver Output Voltage | 12.5 V internally clamped |
| Gate Drive Peak Current | 1.5 A (source/sink) |
| PFC Control Mode | Average current mode with multiplier |
| Protection Features | Cycle-by-cycle OCP, Over Power Limit (OPL), OTP, Input brownout, Output OVP, Output UVP |
| Soft-Start | Integrated |
| Sync Input | Yes (ISET/SYNC pin) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant (Pb-Free) |
ISL6731BFBZ Pin Configuration
| Pin 1 | VCC — Supply voltage for the IC |
| Pin 2 | GND — Analog ground return |
| Pin 3 | OVP/UVP — Output overvoltage and undervoltage protection sense |
| Pin 4 | MULT — Multiplier input (rectified AC line) |
| Pin 5 | IAC — AC line current sense |
| Pin 6 | CAOUT — Current amplifier output |
| Pin 7 | CFF — Feedforward capacitor for line-voltage compensation |
| Pin 8 | VSENSE — Output voltage feedback |
| Pin 9 | COMP — Error amplifier compensation output |
| Pin 10 | CS — Cycle-by-cycle current sense |
| Pin 11 | ISET/SYNC — Frequency-set resistor / sync input |
| Pin 12 | RT/CT — Timing resistor/capacitor for oscillator |
| Pin 13 | GD — Gate driver output to external MOSFET |
| Pin 14 | NC — Not connected (per datasheet) |
Typical Applications
ISL6731BFBZ is suitable for 6 applications: Desktop PC and Server SMPS (80 PLUS), Telecom Rectifier Front End, Industrial SMPS and Welding Inverter Front End, UPS Input PFC Stage, E-Mobility Level 2 AC Charger, LED Driver Front End (High-Bay and Stadium).
Desktop PC and Server SMPS (80 PLUS)
The ISL6731BFBZ is the front-end CCM PFC stage in 80 PLUS-compliant desktop and server SMPS, typically operating from universal 85-264 VAC input and delivering 400 VDC bulk rail at 300 W to 1.5 kW. Its 56.5 kHz to 70.7 kHz switching range, 1.5 A gate drive, and integrated protection suite (OCP, OPL, OTP, brownout, OVP, UVP) deliver >0.99 power factor and <10% THDi required by 80 PLUS Gold and Platinum specifications. Pair with a downstream LLC or phase-shifted full-bridge stage for the DC-DC conversion. Recommend TPS54360 (TI) for the standby rail and UCC25640 (TI) for the LLC controller.
Recommended
Telecom Rectifier Front End
In -48 V telecom rectifier front ends, the ISL6731BFBZ drives the CCM PFC boost stage that converts 85-264 VAC to a 400 VDC intermediate bus, which then feeds an isolated DC-DC stage producing -48 VDC. The 1.5 A gate drive handles high-RDS(on) MOSFETs for >2 kW rectifier modules, while cycle-by-cycle OCP and OVP safeguard against telecom bus short events. The ISET/SYNC pin allows synchronizing to the system clock to minimize EMI in densely packed rectifier shelves. Recommend UCC25640 for the LLC stage and ISO5451 for gate-drive isolation.
Recommended
Industrial SMPS and Welding Inverter Front End
Industrial three-phase and single-phase SMPS, including welding inverter front ends, use the ISL6731BFBZ as the CCM PFC controller to comply with harmonic-current standards (IEC 61000-3-2) and reduce input current distortion below 5%. The 1.5 A peak gate-drive current allows direct driving of large 600 V or 1200 V IGBT/MOSFET switches without external buffer stages, simplifying the BOM and improving reliability. The wide -40 C to +125 C operating range and integrated OTP support harsh industrial enclosures. Recommend UCC25640 for the LLC stage and DRV8350 for any downstream motor-control stage.
Recommended
UPS Input PFC Stage
Online UPS systems in the 1-10 kVA range use the ISL6731BFBZ as the input PFC stage that conditions rectified mains to a stable 400 VDC bus feeding the inverter. Its integrated brownout, OVP, UVP, and OTP protection suite provides the fault coverage UPS systems require to ride through input anomalies and meet IEC 62040-3 power-quality targets. The 1.5 A gate drive supports the high-current boost inductor required for 5 kW+ PFC stages without an external gate driver. Recommend UCC25640 for the auxiliary DC-DC and ISO5451 for inverter-stage gate isolation.
Recommended
E-Mobility Level 2 AC Charger
Level 2 AC EV chargers (6.6 kW to 19.2 kW) use the ISL6731BFBZ as the CCM PFC front-end of the on-board charger module, converting 208-240 VAC single-phase (or 3-phase) input to a 400 VDC battery bus. Two ISL6731BFBZ controllers can be interleaved via the SYNC pin to reduce input current ripple by half and shrink the input EMI filter, satisfying IEC 61851-21-2 conducted emissions limits. The integrated protection suite (OCP, OPL, OTP, brownout, OVP, UVP) meets IEC 61851-1 safety requirements for off-board and on-board EVSE. Recommend UCC25640 for the downstream LLC and ISO5451 for isolation.
Recommended
LED Driver Front End (High-Bay and Stadium)
High-bay and stadium LED drivers in the 500 W to 2 kW range use the ISL6731BFBZ as the CCM PFC front-end to comply with harmonic-current regulations (IEC 61000-3-2 Class C) and supply a clean 400 VDC rail to the downstream LLC or flyback LED-current regulator. The 1.5 A gate drive supports direct switching of large MOSFETs for >1 kW designs, while the integrated OTP and OVP protect against LED-array over-voltage events. Recommend UCC25640 for the LLC stage and TPS92515 for the LED current regulator.
Recommended
Recommended Products Summary
Engineering reference data for ISL6731BFBZ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ISL6731AFBZ | ISL6731BFBZ-T | UCC28019A | NCP1654 | FAN7930MX |
|---|---|---|---|---|---|---|
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics | Texas Instruments | onsemi | onsemi |
| Package | 14-SOIC (M14.15) | 14-SOIC (M14.15) - same | 14-SOIC (M14.15) - same | 14-SOIC - same | 14-SOIC - same | 14-SOIC - same |
| Topology | CCM PFC | CCM PFC | CCM PFC | CCM PFC | CCM PFC | CCM PFC / Boundary |
| Switching Frequency Range | 56.5 kHz to 70.7 kHz | 56.5 kHz to 70.7 kHz | 56.5 kHz to 70.7 kHz | Up to ~65 kHz | Up to ~65 kHz | Variable, CCM mode |
| Gate Drive Peak Current | 1.5 A | 1.5 A | 1.5 A | 1.0 A | 1.0 A | 0.5 A |
| Integrated Brownout Protection | Yes | Yes | Yes | Yes | Yes | Yes |
| Output OVP / UVP | Yes | Yes | Yes | Yes | Yes | Yes |
| Operating Temperature Range | -40 C to +125 C | -40 C to +125 C | -40 C to +125 C | -40 C to +125 C | -40 C to +125 C | -40 C to +125 C |
Key Differentiators
- 1.5 A peak gate-drive current (vs UCC28019A / NCP1654)
- Integrated Over-Power Limit (OPL) (vs UCC28019A)
- Up to 70.7 kHz switching frequency (vs UCC28019A)
- Full SOIC-14 pinout and footprint compatibility (vs FAN7930MX)
Design Notes
Use a star-ground layout with separate analog ground (GND) and power ground returns. The ISL6731BFBZ current-sense resistor should be placed on the inductor return-side (low-side) for accurate cycle-by-cycle OCP, and the CS trace should be kelvin-connected to the resistor pad. Keep the high-current loop (input rectifier - boost inductor - MOSFET - sense resistor - rectifier) tight and minimize the loop area to reduce EMI. Decouple VCC with a 1 uF ceramic in parallel with a 10 uF electrolytic, placed within 5 mm of the IC pin.
Do not place large filter capacitance directly at the IAC input - the multiplier input is high-impedance and capacitive loading will distort the input current waveform, degrading power factor. The multiplier output (MULT) should be AC-coupled to the current amplifier (CAOUT) through a resistor-capacitor network per the datasheet reference circuit. When migrating to UCC28019A or NCP1654, verify the current-sense polarity - some alternatives use high-side sensing while the ISL6731BFBZ uses low-side (return-side) sensing.
At 70.7 kHz switching frequency and 1.5 A gate-drive peak current, the ISL6731BFBZ gate-driver dissipation can reach 0.3 W in a typical 600 V MOSFET application. The 14-SOIC package theta_JA is approximately 100 C/W on a 1 oz 2-layer board, giving a 30 C temperature rise at full load. For enclosed industrial designs with restricted airflow, use a 4-layer board with a dedicated ground plane on layer 2 to drop theta_JA to ~40 C/W and keep junction rise under 15 C. Decoupling the VCC pin and routing the GD trace with 25 mil minimum width further reduces AC losses.
Route the gate-drive (GD) trace as short as possible (<25 mm) and away from the IAC/MULT/VSENSE analog pins to avoid capacitive coupling that injects switching noise into the feedback path. Use the SYNC function (ISET/SYNC pin) to synchronize the ISL6731BFBZ to a fixed system clock when paired with a downstream LLC controller - this dithers the EMI spectrum and reduces peak emissions by 6-10 dB. A common-mode choke on the AC input and an X-capacitor across the rectifier complete a typical 6 dB-margin conducted-EMI filter.
Compliance Information
Pb-Free per Renesas ordering information (M14.15 SOIC package). RoHS/REACH compliance per distributor product listings; halogen-free status not explicitly stated in available data. Not AEC-Q100 qualified - this part targets industrial/commercial SMPS, not automotive.
