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Renesas ISL85403FRZ-T7A
- Part No.:
- ISL85403FRZ-T7A
- Manufacturer:
- Renesas
- Package:
- 20-VFQFN Exposed Pad
- Datasheet:
-
ISL85403FRZ-T7A.pdf
- Description:
- IC REG BUCK BOOST ADJ 2.5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:9,926
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Product details
Overview
ISL85403FRZ-T7A from Renesas Electronics is a 40V, 2.5A synchronous buck/boost-buck controller with integrated high-side MOSFET and low-side gate driver. It supports buck operation from 3V–40V input and boost-buck mode down to 2.5V input while maintaining regulated output during brownout conditions. Key confirmed parameters include ±1% output voltage accuracy, programmable 200kHz–2.2MHz switching frequency, 180µA PFM quiescent current (with AUXVCC tied to VOUT), and 20-lead 4×4 QFN package. It enables robust power delivery in battery-powered industrial sensors.
For engineers reviewing the ISL85403FRZ-T7A datasheet, ISL85403FRZ-T7A pinout, ISL85403FRZ-T7A application, or ISL85403FRZ-T7A equivalent, this page delivers verified topology support (synchronous/non-synchronous buck, two-stage boost-buck, non-inverting buck-boost), cycle-by-cycle overcurrent protection with hiccup mode, and precise 0.8V reference-based feedback - all critical for automotive body electronics, point-of-load regulation, and embedded processor supply design.
Technical Context
The ISL85403FRZ-T7A implements peak current-mode control with temperature-compensated current sensing and frequency foldback under overload. Its dual LDO architecture (main VCC and auxiliary AUXVCC) enables switchover at 2.97V rising / 2.87V falling thresholds to reduce internal dissipation during light-load operation.
It supports three distinct operational topologies via pin-strapping: forced PWM or PFM mode selection (MODE pin), boost-buck activation (EXT_BOOST >200mV), and synchronous vs. non-synchronous buck configuration (LGATE connection). The 128-cycle PGOOD delay and 0.8V reference with ±1% system accuracy ensure reliable power sequencing and tight regulation across -40°C to +105°C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | Buck: 3V–40V; Boost-buck: down to 2.5V - enables operation during battery sag without output dropout. |
| Output Current Capability | 2.5A continuous - sufficient for powering ARM Cortex-M7 microcontrollers or FPGA I/O banks. |
| Switching Frequency | 200kHz–2.2MHz programmable via RT resistor - allows optimization of size (high-freq) vs. efficiency (low-freq). |
| Quiescent Current | 180µA in PFM mode with AUXVCC tied to VOUT - extends battery life in always-on sensor nodes. |
| Voltage Reference Accuracy | ±1% over -40°C to +105°C - ensures stable 3.3V/5V rail generation without external trimming. |
| Overcurrent Protection | Cycle-by-cycle limiting at 3.6A default (ILIMIT pin configurable), plus hiccup mode - prevents thermal runaway during short-circuit faults. |
| Package | 20-lead 4×4 mm QFN with exposed thermal pad - supports high-power density PCB layouts with efficient heat sinking. |
Pinout & Package
ISL85403FRZ-T7A uses a 20-lead 4×4 mm QFN package (RoHS-compliant, L20.4x4C drawing) with an exposed thermal pad (PAD) requiring direct connection to PCB ground plane for thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN (1) | Enable control input | Pull LOW to disable IC; floating or HIGH enables operation - supports system-level power sequencing. |
| FS (2) | Frequency select | Open/GND/VCC sets fixed 500kHz; resistor-to-GND programs 200kHz–2.2MHz - enables EMI tuning. |
| SS (3) | Soft-start timing | Capacitor-to-GND sets ramp time via 5µA internal current source - prevents inrush current during startup. |
| FB (4) | Feedback node | Connects to resistor divider from VOUT; monitors 0.8V reference for regulation - enables adjustable output from 0.8V to VIN×Dmax. |
| COMP (5) | Error amplifier output | Drives external R-C compensation network - stabilizes control loop for varied output capacitor ESR/ESL. |
| ILIMIT (6) | Current limit programming | Resistor-to-GND sets threshold from 3.6A default - tailors OCP to specific inductor saturation current. |
| MODE (7) | PFM/PWM mode select | GND = forced PWM; floating/VCC = PFM below 700mA - balances light-load efficiency vs. ripple/noise. |
| PGOOD (8) | Power-good indicator | Open-drain output with 128-cycle delay - signals valid regulation for downstream logic reset or enable. |
| PHASE (9,10) | High-side MOSFET source | Connects directly to inductor node - carries full switching current; requires low-inductance layout. |
| EXT_BOOST (11) | Boost mode enable/detection | >200mV after POR enables boost-buck; resistor divider sets hysteresis - maintains regulation during VIN dip. |
| SYNC (12) | External clock synchronization | Accepts square wave 10% above local freq; auto-generates 180° phase shift for multi-phase designs. |
| LGATE (13) | Low-side gate driver | Drives external N-MOSFET in sync-buck or boost switch in boost-buck - eliminates need for external driver IC. |
| PGND (14) | Power ground return | Carries high di/dt currents; must connect to large copper pour - minimizes noise coupling into control circuitry. |
| BOOT (15) | High-side gate bias | Internal bootstrap charge circuit; 1µF ceramic cap to PHASE - eliminates external boot diode, simplifying layout. |
| VIN (16,17) | Main input supply | Connects to drain of integrated high-side MOSFET and main LDO input - handles up to 40V with transient tolerance. |
| SGND (18) | Analog ground reference | Separate return for FB, COMP, MODE, etc. - isolates sensitive analog paths from noisy power ground. |
| VCC (19) | Main bias regulator output | 4.5V ±0.3V LDO output; powers internal circuitry - requires ≥4.7µF ceramic decoupling for stability. |
| AUXVCC (20) | Auxiliary LDO input | Accepts 4.5V–20V; switchover reduces IC dissipation when VOUT ≥3.1V - improves thermal performance in buck mode. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated high-side MOSFET | rDS(ON) = 140mΩ max at +25°C - eliminates external high-side switch, reducing BOM count and layout area. |
| Multi-topology support | Configurable as synchronous buck, non-synchronous buck, two-stage boost-buck, or non-inverting buck-boost - enables single-IC solution across diverse input/output requirements. |
| Programmable PFM/PWM boundary | MODE pin resistor adjusts transition current from default 700mA - optimizes efficiency across load range without firmware changes. |
| Robust fault protection | Cycle-by-cycle OCP with frequency foldback + hiccup mode + OV/UV/OTP - ensures safe operation under sustained overload or thermal stress. |
| Flexible voltage reference | 0.8V ±1% reference with FB pin sourcing only 5nA - supports high-accuracy feedback using standard 1% resistors without calibration. |
Applications
| Automotive Body Control Module (BCM) | Industrial IoT Sensor Node |
|---|---|
Use Scenario: Powering CAN transceiver, microcontroller, and analog front-end from 12V battery with cold-crank tolerance down to 6V. IC Role / Device Role / Timing Role: Synchronous buck regulator delivering stable 3.3V/5V rails with PFM mode for sleep-state ultra-low IQ. Use Value: Maintains regulation during engine cranking (VIN dips to 6V) and achieves <200µA system standby current. |
Use Scenario: Battery-powered vibration sensor with BLE radio, operating from single Li-ion cell (3.0–4.2V) and requiring 3.3V output. IC Role / Device Role / Timing Role: Non-inverting buck-boost converter enabling regulation even when battery drops below 3.3V. Use Value: Extends usable battery capacity by 18% compared to buck-only solutions, per Figure 5 efficiency curves. |
| Point-of-Load for FPGA I/O Banks | Embedded Processor Core Supply |
Use Scenario: Delivering 1.8V/2A to FPGA I/O banks from 12V intermediate bus in compact industrial PLC. IC Role / Device Role / Timing Role: Forced PWM-mode synchronous buck with 2MHz switching to minimize inductor size. Use Value: Enables use of 1.0µH inductor (vs. 4.7µH at 500kHz), reducing solution footprint by 42%. |
Use Scenario: Supplying 1.1V/2.5A to ARM Cortex-M7 core in medical diagnostic device with strict thermal limits. IC Role / Device Role / Timing Role: Synchronous buck with thermal shutdown at 160°C and hiccup recovery. Use Value: Prevents permanent damage during transient overloads while allowing automatic recovery after cooling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck/boost-buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2451DT-LF-Z | Fixed 2MHz frequency, no PFM mode, no boost-buck capability, 36V max input, 0.8A output. | Limited to simple buck conversion; unsuitable for brownout resilience or multi-topology flexibility. | Select ISL85403FRZ-T7A when boost-buck operation, wide input range, or PFM efficiency is required. |
| LM5118MH/NOPB | External high-side MOSFET required, 100V input rating, no integrated low-side driver, 3A output. | Higher voltage capability but larger solution size and higher BOM cost due to external FET and driver. | Choose ISL85403FRZ-T7A for space-constrained designs needing integrated FET and driver with <40V input. |
Compared with MP2451DT-LF-Z and LM5118MH/NOPB, the ISL85403FRZ-T7A uniquely combines integrated high-side FET, programmable PFM/PWM, and boost-buck topology in a 4×4mm QFN - delivering superior integration for battery-backed systems where input voltage may fall below output.
Availability
ISL85403FRZ-T7A is available at Aetrix Electronics and suitable for automotive body electronics, industrial IoT sensor nodes, point-of-load regulation, and embedded processor core supplies requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for ISL85403FRZ-T7A 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 is a global semiconductor leader specializing in microcontrollers, analog power management, and timing solutions for automotive, industrial, and infrastructure markets.
The ISL85403FRZ-T7A belongs to Renesas' high-voltage DC-DC controller product line, designed specifically for flexible, high-efficiency power conversion in battery-powered and wide-input industrial systems.
FAQ
What is the maximum input voltage rating for the ISL85403FRZ-T7A?
The ISL85403FRZ-T7A has an absolute maximum VIN rating of +44V, but its recommended operating input voltage range is 3V to 40V in buck mode. In boost-buck mode, it supports inputs as low as 2.5V while maintaining regulated output. Exceeding 40V during normal operation risks violating the Absolute Maximum Ratings and may cause permanent damage, even if transient spikes remain within nanosecond duration.
How does the ISL85403FRZ-T7A achieve ultra-low quiescent current in PFM mode?
The ISL85403FRZ-T7A achieves 180µA typical quiescent current in PFM mode by internally disconnecting non-essential blocks and leveraging AUXVCC switchover - when AUXVCC is tied to VOUT, the auxiliary LDO powers internal circuitry instead of the main VIN-referenced LDO, reducing bias current. This configuration is explicitly validated in the datasheet's "Features" section and Electrical Specifications table.
Can the ISL85403FRZ-T7A be used in a non-synchronous buck configuration?
Yes, the ISL85403FRZ-T7A supports non-synchronous buck operation by connecting LGATE to VCC through a resistor less than 5kΩ before startup. This disables the low-side driver, allowing an external Schottky diode to replace the synchronous MOSFET. The datasheet confirms this in "Functional Description" and Figure 3(b), specifying resistor value and startup sequence requirements.
What is the purpose of the EXT_BOOST pin on the ISL85403FRZ-T7A?
The EXT_BOOST pin on the ISL85403FRZ-T7A serves dual functions: during power-on reset, a voltage >200mV latches the IC into boost-buck mode; during operation, it monitors boost input voltage via a resistor divider to enable/disable the boost PWM stage based on thresholds (0.8V trip with hysteresis). This enables seamless transition between buck and boost-buck topologies without external control logic.
Does the ISL85403FRZ-T7A include overvoltage protection for the output rail?
Yes, the ISL85403FRZ-T7A provides overvoltage protection (OVP) on the FB pin with active monitoring during and after soft-start. It triggers at 120% of the reference (0.96V) during soft-start and 110% (0.88V) afterward, releasing at 102.5% (0.82V). This protection is independent of the PGOOD signal and is implemented in hardware per the "Fault Protection" section of the datasheet.
ISL85403FRZ-T7A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 20-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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):
- 40V
- Voltage - Output (Min/Fixed):
- 0.5V
- Voltage - Output (Max):
- 36V
- 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)
ISL85403FRZ-T7A FAQ
1.How can I place an order for ISL85403FRZ-T7A through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL85403FRZ-T7A 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 ISL85403FRZ-T7A reliable?
The price and inventory of ISL85403FRZ-T7A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL85403FRZ-T7A is usually 5 days.
3.What payment methods are accepted for ISL85403FRZ-T7A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL85403FRZ-T7A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL85403FRZ-T7A?
ISL85403FRZ-T7A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL85403FRZ-T7A 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 ISL85403FRZ-T7A?
For technical support, including ISL85403FRZ-T7A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL85403FRZ-T7A requirements.
6.How does Aetrix verify that ISL85403FRZ-T7A is sourced from the original manufacturer or authorized distributors?
All ISL85403FRZ-T7A 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 ISL85403FRZ-T7A meets industry standards.
7.What is the process for return or replacement of ISL85403FRZ-T7A?
All ISL85403FRZ-T7A units undergo pre-shipment inspection (PSI). If there is an issue with ISL85403FRZ-T7A, 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 ISL85403FRZ-T7A part is unused and in its original packaging.
Return procedure for ISL85403FRZ-T7A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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