Renesas ISL91133IIQZ-T

Overview

ISL91133IIQZ-T from Renesas Electronics is a high-efficiency 2.3A synchronous boost regulator with integrated input-to-output bypass functionality, designed for single-cell Li-ion/Li-polymer battery systems. It delivers up to 2.3A at 3.3V output from 2.5V input, features 38mΩ bypass MOSFET, 2.5MHz switching frequency, and supports fixed 5.0V/5.2V dual-output selection via VSEL pin - used in USB OTG power sources and RF power amplifier biasing.

For engineers reviewing the ISL91133IIQZ-T datasheet, ISL91133IIQZ-T pinout, ISL91133IIQZ-T application, or ISL91133IIQZ-T equivalent, key selection criteria include its forced/auto bypass mode behavior, 45µA quiescent current in Forced Bypass, 5.0V/5.2V output variants, WLCSP-16 package thermal performance (θJA = 70°C/W), and compatibility with 0.47µH inductors and 22µF ceramic output capacitors.

Technical Context

The ISL91133IIQZ-T implements valley-current-mode PWM control with internal N- and P-channel MOSFETs (r_{DSON_N} = 45mΩ, r_{DSON_P} = 40mΩ at 3.5V) and integrates a dedicated 38mΩ bypass P-MOSFET (Q3) for low-dropout operation. Its dual-mode architecture switches between 2.5MHz PWM and PFM at light load, with automatic transition thresholds of 300mA (PWM→PFM) and 500mA (PFM→PWM).

Bypass entry is controlled via BYPS pin logic (LOW = Forced Bypass, HIGH = Auto Bypass), where Auto Bypass triggers when VIN exceeds VOUT by 1.5% for 5µs without switching activity. Soft-start uses two-stage linear current sourcing (ILIN1 = 350mA, ILIN2 = 700mA) specific to the IIQZ variant, with 1200µs regulation time under 50Ω load.

Key Specifications

Pinout & Package

ISL91133IIQZ-T is housed in a 16-ball, 0.4mm pitch, 1.78mm × 1.78mm Wafer-Level Chip-Scale Package (WLCSP) per drawing W4x4.16E, with non-solder-mask-defined (NSMD) pads and MSL3 moisture sensitivity rating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar boost regulator with bypass applications.

Compared with TPS61088RHLR and MAX77818EWJ+T, the ISL91133IIQZ-T uniquely integrates a 38mΩ bypass switch with dedicated BYPS pin control and ultra-low 45µA forced-bypass IQ - making it optimal for space-constrained, battery-life-sensitive USB OTG and RF PA applications where discrete bypass implementation is impractical.

Availability

ISL91133IIQZ-T is available at Aetrix Electronics and suitable for USB OTG power sources, smartphone camera flash drivers, and 4G LTE RF power amplifier biasing requiring stable component supply across consumer electronics production cycles.

Supply support for ISL91133IIQZ-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 is a global semiconductor leader delivering microcontrollers, analog power, and SoC solutions for automotive, industrial, and IoT markets, with emphasis on energy efficiency and system integration.

The ISL91133 product line targets portable battery-powered devices needing high-efficiency, small-footprint DC-DC conversion with intelligent bypass capability - specifically engineered for smartphones, tablets, and wireless infrastructure where battery life and thermal density are critical.

FAQ

What output voltage options does the ISL91133IIQZ-T support?

The ISL91133IIQZ-T supports two factory-configured output voltages: 5.0V (VSEL = LOW) and 5.2V (VSEL = HIGH). This dual-level selection compensates for load transient droop and ensures USB OTG VBUS compliance across varying cable resistances and peripheral loads. The VSEL pin must be hard-wired to GND or VIN during PCB layout - no dynamic switching is supported in operation.

How does the ISL91133IIQZ-T enter Forced Bypass mode?

The ISL91133IIQZ-T enters Forced Bypass mode when the BYPS pin is pulled LOW. In this state, both Q2 (boost P-MOSFET) and Q3 (bypass P-MOSFET) turn ON while the rest of the IC disables - routing VIN directly to VOUT through the 38mΩ Q3 channel. If VOUT > VIN at entry, ISL91133IIQZ-T first discharges VOUT to VIN level using an internal circuit before enabling bypass, preventing reverse current flow into the battery.

What is the soft-start behavior specific to the ISL91133IIQZ-T?

The ISL91133IIQZ-T implements a variant-specific two-stage linear soft-start: Stage 1 delivers 350mA constant current, Stage 2 delivers 700mA constant current. Total soft-start time to regulation is 1200µs under 50Ω load. This slower ramp (vs. 600µs for lower-VOUT variants) prevents overshoot and inrush when powering 5V rails with large output capacitance typical in USB OTG designs.

Does the ISL91133IIQZ-T provide reverse current protection?

Yes, the ISL91133IIQZ-T provides reverse current protection during Forced Bypass mode entry. When BYPS is pulled LOW and VOUT > VIN, the device activates an internal discharge circuit to bring VOUT down to VIN before enabling the bypass FET Q3. This prevents reverse current from flowing from the output capacitor or connected peripheral back into the battery, protecting cell longevity and meeting USB specification requirements.

What thermal performance can be expected from the ISL91133IIQZ-T in its WLCSP package?

The ISL91133IIQZ-T in its 1.78mm × 1.78mm WLCSP package has a typical junction-to-ambient thermal resistance (θ_JA) of 70°C/W and junction-to-board (θ_JB) of 14°C/W. With proper PCB layout - including exposed thermal pad soldered to solid PGND plane and ≥4 thermal vias - the device sustains 2.3A output at +85°C ambient without thermal shutdown, as verified in Renesas' FN8680 characterization data.