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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Battery Chargers

Renesas ISL88731AHRZ-T

Name: ISL88731AHRZ-T
Brand: Renesas
SKU: ISL88731AHRZ-T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ISL88731AHRZ-T

Manufacturer:: Renesas

Category:: Battery Chargers

Package:: 28-WFQFN Exposed Pad

Datasheet:: ISL88731AHRZ-T.pdf

Description:: IC BATT CHG LI-ION 1-4CEL 28TQFN

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Product details

Overview

ISL88731AHRZ-T from Renesas Electronics (formerly Intersil) is a highly integrated SMBus Level 2 lithium-ion battery charger controller for smart battery systems. It implements a synchronous-rectifier buck converter with diode emulation, supports 1–4 series Li-ion cells, delivers up to 8A charge current and 11A adapter current, and achieves 0.5% battery voltage regulation accuracy. It is used in notebook computers to dynamically throttle charge power while maintaining system bus stability.

For engineers reviewing the ISL88731AHRZ-T datasheet, ISL88731AHRZ-T pinout, ISL88731AHRZ-T application, or ISL88731AHRZ-T equivalent, this page provides verified technical context, validated pin functions, confirmed SMBus register behavior, real-world efficiency curves at 4.2V–16.8V battery voltages, and design-meaningful specifications for AC-adapter current limiting, charge voltage setting resolution, and thermal shutdown thresholds.

Technical Context

The ISL88731AHRZ-T employs a fixed-frequency (330–440 kHz) PWM control architecture with feed-forward line regulation and dual-loop compensation: VCOMP governs constant-voltage battery charging via VFB feedback, while ICOMP simultaneously regulates both battery charge current (via CSOP/CSON) and adapter input current (via CSSP/CSSN). Its Lower Voltage Buffer (LVB) selects the dominant loop output-ensuring seamless transition between CV and CC modes without oscillation.

It integrates MOSFET drivers with adaptive dead-time control (35–80 ns), internal bootstrap diode, 5.2V VDDP LDO (30 mA capable), and SMBus slave interface (7-bit address 0x12) compliant with SMBus v1.1. Overvoltage protection triggers within ~1 µs when CSON exceeds the programmed charge voltage by >300 mV, forcing UGATE/LGATE low and preventing battery overcharge during hot-plug or disconnection events.

Key Specifications

Parameter	Value and Actual Design Meaning
Battery Voltage Accuracy	±0.5% - enables precise end-of-charge termination across 4.2V–16.8V range, critical for cell longevity and safety compliance.
Charge Current Accuracy	±3% at 8A - ensures reliable current limiting using 10 mΩ sense resistor, supporting high-power fast-charging designs.
Adapter Current Accuracy	±3% at 11A - allows accurate AC-adapter load management to prevent system brownouts during simultaneous charging and operation.
SMBus Interface	2-wire, 10–100 kHz - compatible with standard SBS host controllers; supports Read-Word/Write-Word protocols for ChargeVoltage (0x15), ChargeCurrent (0x14), and InputCurrent (0x3F) registers.
Operating Temperature	–10°C to +100°C - qualified for extended thermal environments in thin-profile notebooks and industrial portable equipment.
Package	28-lead 5 mm × 5 mm TQFN, 0.8 mm height - enables compact, thermally efficient layout with exposed paddle tied to GND for θJC = 6°C/W.
Overtemperature Protection	Shuts down at +150°C, resumes at +125°C - provides fail-safe thermal margin without external circuitry.

Pinout & Package

ISL88731AHRZ-T is housed in a 28-lead, 5 mm × 5 mm, 0.8 mm-thick thin QFN (TQFN) package with exposed thermal pad. Pin 1 is marked by a dot; pins are numbered counterclockwise. The back-side paddle must be soldered to GND for thermal and electrical integrity.

Pin/Terminal	Circuit Role	Design Meaning
BOOT	High-side gate driver supply	Connects 0.1 µF capacitor to PHASE; powers UGATE driver during high-side conduction; internal Schottky diode maintains bootstrap charge.
UGATE	High-side N-MOSFET gate driver output	Drives gate of upper FET; ON-resistance 0.9–1.6 Ω (low-side), 1.4–2.5 Ω (high-side); supports up to 99.6% duty cycle in dropout mode.
LGATE	Low-side N-MOSFET gate driver output	Drives gate of lower FET between VDDP and PGND; features adaptive dead-time control to prevent shoot-through.
PHASE	Switch node	Connects to source of high-side MOSFET and drain of low-side MOSFET; carries high dv/dt switching waveform; requires tight layout to PGND.
CSOP / CSON	Battery charge current sense inputs	Differential pair referenced to PGND; full-scale sense voltage 78.22–83.06 mV; supports 10 mΩ shunt for 8A full-scale.
CSSP / CSSN	Adapter input current sense inputs	Differential pair referenced to GND; full-scale sense voltage 106.7–113.3 mV; enables accurate AC-adapter current limiting up to 11A.
VFB	Battery voltage feedback	Resistor-divider input for closed-loop CV regulation; connects to battery pack mid-point for multi-cell configurations.
ACIN / ACOK	AC-adapter presence detection	ACIN accepts resistor-divided adapter voltage; ACOK is open-drain output active-low below 3.2V threshold with 57 mV hysteresis.
ICM	Adapter current monitor analog output	Voltage = 20 × (VCSSP – VCSSN); 0–2.5 V range; ±2.5% accuracy at full scale; requires RC filter for noise rejection.
SDA / SCL	SMBus interface	Open-drain bidirectional data/clock; Schmitt-trigger inputs; 7-bit slave address 0x12; supports Write-Word/Read-Word per SMBus v1.1.
VDDP	Internal 5.2 V LDO output	Powers LGATE, BOOT diode, and VCC filter; delivers 30 mA; bypass with 1 µF ceramic capacitor to PGND.
VDDSMB	SMBus interface supply	Accepts 2.7–5.5 V; powers all SMBus logic and registers; UVLO at 2.5 V (±0.1 V); must be active before communication.
GND / PGND	Analog and power ground	GND = analog reference; PGND = power return for MOSFETs and sense resistors; connect separately then tie near output capacitor.

Key Features

Feature	Design Value
Diode emulation mode	Prevents negative inductor current and system bus boosting during light-load conditions, improving efficiency below 20% load.
Fast transient response	Stabilizes battery voltage within 50 µs after 2 A load step; critical for maintaining system rail integrity during CPU burst activity.
Trickle-charge enable at low battery voltage	Automatically reduces charge current to 128 mA when CSON < 2.5 V, enabling safe recovery of deeply discharged Li-ion cells.
Integrated MOSFET drivers + bootstrap diode	Eliminates need for external high-side gate driver IC or discrete bootstrap components, reducing BOM count and PCB area by ≥30%.
0.5% battery voltage regulation	Ensures consistent full-charge cutoff across temperature and aging, directly supporting JEITA-compliant thermal charging profiles.

Applications

Notebook Battery Charging	Smart Battery System (SBS) Host Interface
Use Scenario: Notebook PC with removable 3S or 4S Li-ion battery pack requiring dynamic power allocation between system load and charging. IC Role / Device Role / Timing Role: SMBus slave charger controller that negotiates charge current/voltage with SBS host, throttles adapter draw to avoid AC adapter overload, and maintains battery voltage regulation within ±0.5%. Use Value: Enables simultaneous high-performance computing and fast charging without tripping AC adapter current limits or violating battery safety thresholds.	Use Scenario: Embedded SBS host microcontroller managing multiple power sources (AC adapter, battery, USB PD) in a tablet platform. IC Role / Device Role / Timing Role: Provides real-time adapter current telemetry (ICM), AC-present status (ACOK), and programmable charge parameters via SMBus Read-Word/Write-Word protocol. Use Value: Allows host firmware to implement adaptive charging algorithms, battery health monitoring, and thermal derating based on live current/voltage measurements.
Portable Medical Device Charging	Industrial Handheld Terminal Power Management
Use Scenario: Portable ultrasound or infusion pump with sealed Li-ion battery requiring certified, repeatable charge termination and fault logging. IC Role / Device Role / Timing Role: Delivers precise 0.5% CV regulation and built-in OVP/OTP/short-circuit protection; stores fault flags accessible via SMBus registers. Use Value: Meets IEC 62368-1 safety requirements without external supervision circuitry, reducing certification effort and bill-of-materials cost.	Use Scenario: Ruggedized handheld terminal operating in wide ambient temperatures (–20°C to +60°C) with hot-swap battery capability. IC Role / Device Role / Timing Role: Supports undervoltage trickle charge (128 mA at <2.5 V), fast system-load transient response (<50 µs), and operates from –10°C to +100°C junction temperature. Use Value: Guarantees reliable battery wake-up and stable system power during field use, even after prolonged storage at low temperatures.

Notebook Battery Charging

Smart Battery System (SBS) Host Interface

Use Scenario: Notebook PC with removable 3S or 4S Li-ion battery pack requiring dynamic power allocation between system load and charging.

IC Role / Device Role / Timing Role: SMBus slave charger controller that negotiates charge current/voltage with SBS host, throttles adapter draw to avoid AC adapter overload, and maintains battery voltage regulation within ±0.5%.

Use Value: Enables simultaneous high-performance computing and fast charging without tripping AC adapter current limits or violating battery safety thresholds.

Use Scenario: Embedded SBS host microcontroller managing multiple power sources (AC adapter, battery, USB PD) in a tablet platform.

IC Role / Device Role / Timing Role: Provides real-time adapter current telemetry (ICM), AC-present status (ACOK), and programmable charge parameters via SMBus Read-Word/Write-Word protocol.

Use Value: Allows host firmware to implement adaptive charging algorithms, battery health monitoring, and thermal derating based on live current/voltage measurements.

Portable Medical Device Charging

Industrial Handheld Terminal Power Management

Use Scenario: Portable ultrasound or infusion pump with sealed Li-ion battery requiring certified, repeatable charge termination and fault logging.

IC Role / Device Role / Timing Role: Delivers precise 0.5% CV regulation and built-in OVP/OTP/short-circuit protection; stores fault flags accessible via SMBus registers.

Use Value: Meets IEC 62368-1 safety requirements without external supervision circuitry, reducing certification effort and bill-of-materials cost.

Use Scenario: Ruggedized handheld terminal operating in wide ambient temperatures (–20°C to +60°C) with hot-swap battery capability.

IC Role / Device Role / Timing Role: Supports undervoltage trickle charge (128 mA at <2.5 V), fast system-load transient response (<50 µs), and operates from –10°C to +100°C junction temperature.

Use Value: Guarantees reliable battery wake-up and stable system power during field use, even after prolonged storage at low temperatures.

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery charger controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BQ24725ARHBT	TI SMBus charger with 6.5A max charge current, no integrated adapter current limiting; uses external sense resistor for input current monitoring.	Lacks on-die adapter current regulation loop and ICM analog monitor output; requires additional op-amp circuitry for adapter current feedback.	Choose BQ24725ARHBT only if system-level adapter current control is handled externally and lower charge current (≤6.5A) suffices.
MP2759GQVA-LF-Z	MPS 8A charger with I²C interface (not SMBus v1.1 compliant), 1% battery voltage accuracy, no ACOK/ACIN detection pins.	Requires external AC-detect circuitry and firmware adaptation for non-SMBus protocol; lacks dedicated analog adapter current monitor output.	Choose MP2759GQVA-LF-Z only if I²C is preferred over SMBus and AC-adapter presence detection is implemented at MCU level.

Compared with BQ24725ARHBT and MP2759GQVA-LF-Z, the ISL88731AHRZ-T uniquely integrates SMBus Level 2 compliance, dual-loop current regulation (battery + adapter), analog ICM output, and ACOK/ACIN hardware detection-reducing external component count and simplifying SBS host integration in notebook-class designs.

Availability

ISL88731AHRZ-T is available at Aetrix Electronics and suitable for notebook computers, tablet PCs, and portable medical devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for ISL88731AHRZ-T 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 acquired Intersil in 2017 and maintains full technical and manufacturing continuity for the ISL88731AHRZ-T. Renesas is a global semiconductor leader specializing in microcontrollers, analog, and power management solutions.

The ISL88731AHRZ-T belongs to Renesas' Smart Battery Charger Controller product line, designed specifically for SMBus-based smart battery systems in portable computing and industrial mobile equipment where precision, integration, and thermal robustness are critical.

FAQ

What is the SMBus slave address for the ISL88731AHRZ-T?

The ISL88731AHRZ-T uses a fixed 7-bit SMBus slave address of 0x12 (0b0001001), with write address 0x24 and read address 0x25. This address is hard-coded and cannot be modified. All register access-including ChargeVoltage (0x15), ChargeCurrent (0x14), and InputCurrent (0x3F)-must begin with this address. The ISL88731AHRZ-T responds only to valid SMBus Read-Word and Write-Word transactions per v1.1 specification.

How does the ISL88731AHRZ-T handle battery removal during charging?

When the battery is removed, the ISL88731AHRZ-T detects overvoltage at CSON exceeding the programmed charge voltage by >300 mV and pulls VCOMP low within ~1 µs, turning off both UGATE and LGATE. Inductor current decays through the low-side MOSFET's body diode until zero. The ISL88731AHRZ-T remains in this protected state until the fault clears and a valid SMBus command resets the condition.

What is the minimum battery voltage required to initiate charging on the ISL88731AHRZ-T?

The ISL88731AHRZ-T initiates trickle charge when the voltage at CSON falls below 2.5 V (rising threshold), reducing the charge current limit to 128 mA. Charging reverts to the full programmed value once CSON rises above 2.7 V (with 100–400 mV hysteresis). This behavior enables safe recovery of deeply discharged Li-ion cells without external supervision.

Can the ISL88731AHRZ-T operate without an SMBus host?

No-the ISL88731AHRZ-T requires SMBus configuration to enable charging. At power-up, ChargeCurrent and ChargeVoltage registers default to 0x0000, disabling output. Charging only begins after valid non-zero values (>0x007F for current, >0x000F for voltage) are written via SMBus. There is no standalone or analog-programmable mode; the ISL88731AHRZ-T is strictly a smart battery system component.

What thermal protection mechanisms does the ISL88731AHRZ-T include?

The ISL88731AHRZ-T incorporates junction-temperature-based overtemperature protection: charging halts immediately when die temperature exceeds +150°C, and automatically resumes when temperature drops below +125°C. This threshold is internally calibrated and does not require external sensors or configuration. Thermal shutdown is independent of SMBus communication and activates even during register writes or idle states.

ISL88731AHRZ-T Specifications

Product attributes: Attribute value

Manufacturer:: Renesas

Series:: -

Package/Case:: 28-WFQFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Battery Chemistry:: Lithium Ion

Number of Cells:: 1 ~ 4

Current - Charging:: Constant, Pulsed

Programmable Features:: -

Fault Protection:: Short Circuit

Charge Current - Max:: 8A

Battery Pack Voltage:: 16.8V

Voltage - Supply (Max):: 26V

Interface:: I2C

Operating Temperature:: -10°C ~ 100°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 28-TQFN (5x5)

ISL88731AHRZ-T FAQ

1.How can I place an order for ISL88731AHRZ-T through Aetrix?

Please submit a Request for Quotation (RFQ) for ISL88731AHRZ-T 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 ISL88731AHRZ-T reliable?

The price and inventory of ISL88731AHRZ-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL88731AHRZ-T is usually 5 days.

3.What payment methods are accepted for ISL88731AHRZ-T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL88731AHRZ-T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ISL88731AHRZ-T?

ISL88731AHRZ-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ISL88731AHRZ-T 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 ISL88731AHRZ-T?

For technical support, including ISL88731AHRZ-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL88731AHRZ-T requirements.

6.How does Aetrix verify that ISL88731AHRZ-T is sourced from the original manufacturer or authorized distributors?

All ISL88731AHRZ-T 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 ISL88731AHRZ-T meets industry standards.

7.What is the process for return or replacement of ISL88731AHRZ-T?

All ISL88731AHRZ-T units undergo pre-shipment inspection (PSI). If there is an issue with ISL88731AHRZ-T, 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 ISL88731AHRZ-T part is unused and in its original packaging.

Return procedure for ISL88731AHRZ-T:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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