Overview
Description
The ISL85403 is a 40V, 2. 5A synchronous buck or boost-buck controller with an integrated high-side MOSFET and low-side driver. In Buck mode, the ISL85403 supports a wide input range of 3V to 40V. In Boost-Buck mode, the input range can be extended down to 2. 5V and output regulation can be maintained when VIN drops below VOUT, enabling sensitive electronics to remain on in low input voltage conditions. The ISL85403 has a flexible selection of Forced PWM mode and PFM mode. In PFM mode, the quiescent input current is as low as 180µA (AUXVCC connected to VOUT). The load boundary between PFM and PWM can be programmed to cover wide applications. The low-side driver can either be used to drive an external low-side MOSFET for a synchronous buck or left unused for a standard non-synchronous buck. The low-side driver can also be used to drive a boost converter as a preregulator followed by a buck controlled by the same IC, which greatly expands the operating input voltage range down to 2. 5V or lower. ISL85403 offers robust current protection. It uses peak current mode control with cycle-by-cycle current limiting. It is implemented with frequency foldback under current limit condition; also, the hiccup overcurrent mode ensures reliable operations under harsh short conditions. The ISL85403 has comprehensive protections against various faults including overvoltage and over-temperature protection.
Features
- Buck mode: input voltage range 3V to 40V
- Boost mode expands operating input voltage lower than 2.5V
- Selectable Forced PWM mode or PFM mode
- 300µA IC quiescent current (PFM, no load); 180µA input quiescent current (PFM, no load, VOUT tied to AUXVCC)
- Less than 5µA (MAX) shutdown input current (IC disabled)
- Operational topologies
- Synchronous buck
- Non-synchronous buck
- Two-stage boost buck
- Non-inverting single inductor buck boost
- Programmable frequency from 200kHz to 2.2MHz and frequency synchronization capability
- ±1% tight voltage regulation accuracy
- Reliable overcurrent protection
- Temperature compensated current sense
- Cycle-by-cycle current limiting with frequency foldback
- Hiccup mode for worst case short condition
- 20 Ld 4x4 QFN package
- Pb-free (RoHS compliant)
Comparison
Applications
Design & Development
Software & Tools
Software & Tools
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Software type
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Company
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| iSim:PE Offline Simulation Tool iSim Personal Edition (iSim:PE) speeds the design cycle and reduces risk early in any project, identifying parts that can be used in current as well as next-generation designs.
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Simulator | Renesas |
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Boards & Kits
Demonstration
ISL85403DEMO1Z
Active
Synchronous Buck Demo Board with 7V to 40V Input Range, 5V 2.5A Output
The ISL85403DEMO1Z demonstration board allows for quick evaluation of the ISL85403 synchronous buck or boost-buck controller in the synchronous buck configuration. It is also used to demonstrate the compact size solution for the wide input voltage range point-of-load (POL) DC/DC converter using...
Recommended Documents:
Evaluation
ISL85403EVAL2Z
Active
Buck-Boost EVB with 8V to 40V Input Range, 12V 1A Output
The ISL85403EVAL2Z board allows for quick evaluation of the ISL85403 synchronous buck or boost-buck controller in the non-inverting buck-boost configuration. It is a cost effective solution for the low-power, wide input voltage range point-of-load (POL) application where both stepping up and...
Recommended Documents:
Reference Designs
Buck-Boost Last Gasp Power Supply for Energy Meter Reference Design
In this reference design, a supercapacitor is used as a backup power supply. The board allows for quick evaluation of the ISL85403 buck/boost controller in the two-stage boost buck configuration and the ISL9001A low dropout linear regulator. It is a cost-effective design for low-power, wide...
Recommended Documents:
Test This Board Remotely
Available on Lab on the Cloud, use our PC-based GUI to instantly start configuring and testing designs in our virtual lab, no physical board needed.
Models
ECAD Models
Schematic symbols, PCB footprints, and 3D CAD models from SamacSys can be found by clicking on the CAD Model links in the Product Options table. If a symbol or model isn't available, it can be requested directly from SamacSys.
Models
| Model - iSim | SXSCH 285 KB | |
| Model - iSim | SXSCH 261 KB | |
| Model - iSim | SXSCH 276 KB | |
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Product Options
Applied Filters:
Support
Support Communities
Get quick technical support online from Renesas Engineering Community technical staff.
Support Communities
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ISL85403 in boost mode only
I need ISL85403 to work only in boost mode. Vin as low as possible, Vout = 16V. I'm guessing highest range for Vin would be close to 16V, since there's no buck operation. I came across the boost-buck circuit, which is "Figure 10. ISL85403EVAL3Z Schematic", taken in this ...
Jan 24, 2022 -
ISL85403 buck-boost configuration, help calculating resistor/inductor values for Vout 5V
... the proper Vout values and it will do the math for me, in here - Idk. Looking at the Figure 10 in "Tips for Using the ISL85403 in Boost-Buck Mode" on p.10 R3 140K from Vout to Fb pin sets the Vout voltage, changing duty cycle of Q1 MOSFET ...
Aug 18, 2021 -
Looking for step-up dc/dc converter with Vin 2.5V , Vout 30V
Hello Team, I am looking for a boost converter with the following requirements : Vin 2.5 To 4V Vout >30V power output 8W, I did not manage to find any boost device that accepts Vin below 4.5V, could you please advise if we have anything to offer? Thanks in ...
Dec 7, 2023