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Renesas ISL85402IRZ
- Part No.:
- ISL85402IRZ
- Manufacturer:
- Renesas
- Package:
- 20-VFQFN Exposed Pad
- Datasheet:
-
ISL85402IRZ.pdf
- Description:
- IC REG BUCK BOOST ADJ 2.5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,352
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Product details
Overview
ISL85402IRZ from Renesas (formerly Intersil) is a synchronous buck controller with integrated 125mΩ high-side MOSFET and low-side gate driver, supporting buck, non-synchronous buck, and two-stage boost-buck topologies. It delivers 2.5A continuous output at 5V with 8–36V input, operates from –40°C to +105°C, and features ±1% voltage regulation accuracy for embedded power supplies.
For engineers reviewing the ISL85402IRZ datasheet, ISL85402IRZ pinout, ISL85402IRZ application, or ISL85402IRZ equivalent, key selection criteria include its programmable 200kHz–2.2MHz switching frequency, PFM mode quiescent current as low as 180µA (with AUXVCC tied to VOUT), hiccup-mode overcurrent protection, and flexible topology support across industrial, battery-powered, and point-of-load systems.
Technical Context
The ISL85402IRZ implements peak current mode control with cycle-by-cycle current limiting and frequency foldback under overload, plus hiccup-mode recovery for sustained short-circuit conditions. Its dual LDO architecture-main bias LDO (VIN-fed) and auxiliary LDO (AUXVCC-fed)-enables automatic switchover to reduce power loss during steady-state operation.
Topology flexibility is achieved via configurable MODE, EXT_BOOST, and LGATE pins: MODE selects forced PWM or PFM; EXT_BOOST enables boost-buck operation by detecting input voltage thresholds; LGATE drives external low-side MOSFETs in synchronous buck or boost stages, or is disabled for diode-based non-synchronous buck.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 36V in buck mode; extends below 2.5V in boost-buck configuration via EXT_BOOST monitoring |
| Output Current | 2.5A continuous at 5V VOUT, 8–36V VIN, 500kHz, +105°C ambient with still air |
| Switching Frequency | Programmable 200kHz–2.2MHz via FS resistor; supports external synchronization on SYNC pin |
| Voltage Regulation Accuracy | ±1% over temperature and line/load, referenced to internal 0.8V bandgap |
| Quiescent Current | 180µA in PFM mode (no load, AUXVCC = VOUT); <3µA in shutdown |
| Overcurrent Protection | Cycle-by-cycle limiting at default 3.6A; hiccup mode triggered at 115% of limit (≈4.14A) |
| Package | 20-lead 4mm × 4mm QFN with exposed thermal pad (RoHS-compliant, Pb-free) |
Pinout & Package
ISL85402IRZ is housed in a 20-lead 4×4 mm QFN package with an exposed thermal pad (PAD, Pin 21) that must be soldered to a large PCB ground plane for thermal management. The package is RoHS-compliant and rated for –40°C to +105°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN (1) | Enable control input | IC enabled when floating or >2V; disabled when pulled <0.8V; internal pull-up current ≤0.8µA at VIN=24V |
| FS (2) | Oscillator frequency setting | Resistor-to-GND sets frequency (200kHz–2.2MHz); open/VCC/GND forces 500kHz |
| SS (3) | Soft-start timing node | 5µA internal current charges external capacitor; controls startup ramp and hiccup-mode dummy soft-start duration |
| FB (4) | Feedback input | Inverting input of error amplifier; senses output via resistor divider; monitors overvoltage/undervoltage |
| COMP (5) | Error amplifier output | Drives PWM comparator; loop compensation implemented with RC network between COMP and FB |
| ILIMIT (6) | Current limit threshold programming | Resistor-to-GND sets cycle-by-cycle OCP threshold (default 3.6A); no resistor = internal default |
| MODE (7) | PFM/PWM mode selection | Pull to GND = forced PWM; float/VCC = PFM; resistor-to-GND programs PWM/PFM boundary current (e.g., 700mA default) |
| PGOOD (8) | Power-good status flag | Open-drain output; asserts low on EN disable, VOUT OV/UV (90%–110% of target), with 1000-cycle delay on power-up |
| PHASE (9,10) | High-side MOSFET source connection | Connects to inductor node; tied internally to source of integrated 125mΩ N-channel high-side MOSFET |
| EXT_BOOST (11) | Boost mode enable & input monitoring | Detects boost input voltage; <200mV → buck mode; >200mV → boost-buck mode; also used for boost OVP sensing |
| SYNC (12) | Frequency synchronization input/output | Accepts external clock (10% higher than local freq); outputs synchronized signal; auto-generates 180° phase shift in multi-IC setups |
| LGATE (13) | Low-side gate driver output | Drives external N-MOSFET in synchronous buck or boost; connect to VCC pre-startup to disable in non-synchronous buck |
| PGND (14) | Power ground return | Return path for high-current switching paths (PHASE, LGATE, BOOT); requires low-impedance connection to large ground plane |
| BOOT (15) | High-side gate driver bootstrap supply | Internal boot circuit generates gate drive voltage; 1µF ceramic cap required between BOOT and PHASE |
| VIN (16,17) | Main input supply | Connects to drain of integrated high-side MOSFET and input to main LDO; absolute max 44V transient, operating max 36V |
| SGND (18) | Analog/monitor ground | Reference for FB, COMP, MODE, ILIMIT, etc.; isolate from PGND to minimize noise coupling into control loop |
| VCC (19) | Main LDO output | 4.5V ±0.3V regulated supply for IC bias; requires ≥4.7µF ceramic decoupling to PGND |
| AUXVCC (20) | Auxiliary LDO input / boost OVP sense | In buck mode: accepts VOUT to enable LDO switchover (reducing dropout loss); in boost mode: senses boost output for OVP |
| PAD (21) | Thermal pad | Electrically isolated; must be soldered to PCB ground plane for thermal conduction (θJC = 3.5°C/W) |
Key Features
| Feature | Design Value |
|---|---|
| Integrated high-side MOSFET | 125mΩ rDS(ON) reduces conduction loss and eliminates external high-side switch component count |
| Topology flexibility | Single IC supports synchronous buck, non-synchronous buck (diode-based), and two-stage boost-buck for ultra-low input voltage operation |
| Ultra-low quiescent current | 180µA in PFM mode with AUXVCC connected to VOUT enables >10-year battery life in always-on IoT sensors |
| Robust fault protection | Hiccup-mode OCP prevents thermal runaway during sustained shorts; temperature-compensated current sense ensures consistent trip across temperature |
| Automatic LDO switchover | Main LDO switches to auxiliary LDO post-startup when AUXVCC >3.1V, reducing bias power dissipation at high VIN |
| Programmable current limit | ILIMIT pin allows precise tuning of OCP threshold (3.0–4.2A) to match inductor saturation and layout constraints |
Applications
| Industrial Motor Control Power | Portable Medical Device Supply |
|---|---|
Use Scenario: Powering microcontrollers, gate drivers, and analog front-ends in servo drives with 24V bus input and variable load demands. IC Role / Device Role / Timing Role: Synchronous buck regulator delivering stable 3.3V/5V rails; uses forced PWM mode for predictable EMI profile during motor commutation. Use Value: Integrated 125mΩ high-side MOSFET and 2.5A capability eliminate discrete FETs and reduce board area by >30% vs. controller-only solutions. | Use Scenario: Long-life battery-powered glucose meters and portable ultrasound probes requiring sub-200µA standby current. IC Role / Device Role / Timing Role: Primary DC-DC converter operating in PFM mode at light loads; leverages 180µA quiescent current and AUXVCC switchover for efficiency. Use Value: Extends single CR2032 battery life beyond 5 years in sleep mode while maintaining fast wake-up response via peak current mode control. |
| Automotive Body Control Module | Point-of-Load for FPGA I/O Banks |
Use Scenario: Regulating 5V rail from 12V vehicle battery in BCMs subject to cold-crank (4.5V) and load-dump (36V) transients. IC Role / Device Role / Timing Role: Buck converter with wide 3–36V input range and hiccup-mode OCP; handles intermittent short circuits from actuator faults. Use Value: Absolute maximum 44V VIN rating and built-in overvoltage/overtemperature protection meet AEC-Q100 stress requirements without external clamping. | Use Scenario: Generating 1.2V/1.8V/3.3V supplies for FPGA I/O banks with tight regulation and fast transient response. IC Role / Device Role / Timing Role: Synchronous buck controller using peak current mode control; COMP/FB loop compensation optimized for ceramic output capacitors. Use Value: ±1% regulation accuracy and <200ns minimum on/off times ensure stable core voltage under dynamic FPGA load steps up to 2A/µs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ISL85403IRZ | Higher 4A continuous output rating; identical pinout, package, and feature set; updated revision with improved thermal performance | Required where >2.5A sustained load or higher ambient temperatures (>+105°C) are present | Select ISL85403IRZ for new designs requiring higher current headroom or extended thermal margin |
| MP2451DT-LF-Z | 36V-input, 2A synchronous buck; no boost-buck capability; fixed 500kHz frequency; lacks PFM mode and AUXVCC switchover | Suitable only for basic buck conversion with fixed frequency and lower current demand | Choose MP2451DT-LF-Z only if topology simplicity and cost outweigh need for PFM efficiency or boost-buck flexibility |
Compared with ISL85402IRZ, the ISL85403IRZ offers direct upgrade path with higher current and thermal robustness, while the MP2451DT-LF-Z provides a lower-cost, functionally limited alternative lacking PFM, boost-buck, and LDO switchover-making ISL85402IRZ optimal for mixed-mode, battery-sensitive, or wide-input industrial applications.
Availability
ISL85402IRZ is available at Aetrix Electronics and suitable for industrial motor control, portable medical devices, automotive body electronics, and FPGA point-of-load power supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for ISL85402IRZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Renesas Electronics Corporation is a global semiconductor leader delivering trusted embedded design innovation, with deep expertise in power management, microcontrollers, and analog solutions.
The ISL85402IRZ belongs to Renesas' high-voltage synchronous buck controller family, designed specifically for industrial, automotive, and battery-powered systems demanding wide input range, topology flexibility, and robust protection in compact 4×4 QFN packages.
FAQ
What is the maximum continuous output current of the ISL85402IRZ?
The ISL85402IRZ delivers 2.5A continuous output current under defined conditions: 5V VOUT, 8–36V VIN, 500kHz switching frequency, and +105°C ambient temperature with still air. Actual maximum current depends on thermal design, board layout, and ambient conditions-die temperature must not exceed +125°C. Derating is required at higher ambient temperatures or lower airflow.
Can the ISL85402IRZ operate in boost-buck topology, and what is required to enable it?
Yes, the ISL85402IRZ supports boost-buck operation. Enable it by applying a voltage >200mV to the EXT_BOOST pin after VCC power-on reset. In this mode, the low-side driver (LGATE) controls the boost switch, while the high-side MOSFET regulates the buck stage. A resistor divider on EXT_BOOST sets boost input UV/OV thresholds, and PFM is disabled during boost PWM activity.
How does the AUXVCC switchover function improve efficiency in the ISL85402IRZ?
The ISL85402IRZ's AUXVCC switchover reduces bias power loss by switching from the main VIN-fed LDO to an auxiliary LDO powered by the regulated output voltage (e.g., VOUT). When AUXVCC rises above 3.1V, the IC disables the main LDO-lowering dropout voltage and internal power dissipation. This improves light-load efficiency, especially at high VIN, and is active only in buck (not boost) mode.
What protection features does the ISL85402IRZ include, and how do they operate?
The ISL85402IRZ integrates cycle-by-cycle current limiting with frequency foldback, hiccup-mode overcurrent protection (triggered at 115% of programmed limit), overvoltage protection (latching at 120% of reference, non-latching at 110%), overtemperature shutdown at +155°C, and power-good monitoring with 2ms delay. All protections are hardware-based and require no external components.
Is the ISL85402IRZ pin-compatible with any newer Renesas parts for design upgrades?
Yes, the ISL85402IRZ is pin-compatible with the ISL85403IRZ, which offers identical 20-lead 4×4 QFN packaging, same pinout, and full functional compatibility-including all modes, protections, and interface signals. The ISL85403IRZ increases continuous output current to 4A and improves thermal resistance, making it a drop-in upgrade for higher-power applications.
ISL85402IRZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 20-VFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Up, Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck, Boost, Buck-Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 34V
- Current - Output:
- 2.5A
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Both
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (4x4)
ISL85402IRZ FAQ
1.How can I place an order for ISL85402IRZ through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL85402IRZ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for ISL85402IRZ reliable?
The price and inventory of ISL85402IRZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL85402IRZ is usually 5 days.
3.What payment methods are accepted for ISL85402IRZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL85402IRZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL85402IRZ?
ISL85402IRZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL85402IRZ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for ISL85402IRZ?
For technical support, including ISL85402IRZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL85402IRZ requirements.
6.How does Aetrix verify that ISL85402IRZ is sourced from the original manufacturer or authorized distributors?
All ISL85402IRZ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ISL85402IRZ meets industry standards.
7.What is the process for return or replacement of ISL85402IRZ?
All ISL85402IRZ units undergo pre-shipment inspection (PSI). If there is an issue with ISL85402IRZ, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The ISL85402IRZ part is unused and in its original packaging.
Return procedure for ISL85402IRZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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