Renesas ISL6534CRZ

Overview

ISL6534CRZ from Renesas (formerly Intersil) is a triple-output voltage regulator IC integrating two synchronous buck PWM controllers (OUT1, OUT2) and one linear controller (OUT3), delivering precision regulation for DDR memory power systems. It supports 0.6V–6V output on buck channels with 12V gate drivers, 300kHz–1MHz adjustable switching frequency, and independent soft-start/enable per channel. Used in DDRAM controller boards requiring tightly coupled VDDQ and VTT rails.

For engineers reviewing the ISL6534CRZ datasheet, ISL6534CRZ pinout, ISL6534CRZ application, or ISL6534CRZ equivalent, key selection considerations include its dual-buck + linear architecture, DDR-specific phase-staggering capability (0°/90°/180°), 3.3V buffered VTT reference (REFOUT), shunt-regulated 5.8V VCC option, and QFN-32 thermal performance (θJA = 32°C/W).

Technical Context

The ISL6534CRZ implements voltage-mode control for both buck regulators, each with dedicated error amplifiers (COMP1/COMP2), internal 0.6V reference (OUT1), external reference input (REFIN for OUT2), and buffered 3.3V VREF/REFOUT outputs. Its FS_SYNC pin enables resistor-based frequency tuning (300kHz–1MHz) or external clock synchronization to eliminate beat frequencies.

OUT3 operates as a linear controller driving an external N-channel MOSFET with 0.6V reference, supporting 0.6V–3.3V output; PGOOD asserts only after all three outputs complete soft-start without short-circuit faults. DDR mode configures OUT1 and OUT2 to share SS1 ramp and use VOUT1-derived REFIN, while Independent mode allows fully decoupled start-up and regulation.

Key Specifications

Pinout & Package

ISL6534CRZ uses a thermally enhanced 32-lead 5×5 mm QFN package (JEDEC MO-220 compliant) with exposed thermal pad tied to GND. Pin numbering follows top-view layout; BOOT2 and UGATE2 positions differ from TSSOP variant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple-output regulator applications.

Compared with ISL6534CRZ, ISL6522CRZ reduces integration (one less buck channel) and eliminates DDR-specific functions, while RT8205AZSP trades frequency flexibility and VCC shunt capability for lower BOM count-neither offers identical phase-control or reference-buffering functionality.

Availability

ISL6534CRZ is available at Aetrix Electronics and suitable for DDR memory power supplies, multi-rail server CPUs, and industrial PLCs requiring stable component supply across extended production lifecycles.

Supply support for ISL6534CRZ 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 acquired Intersil in 2017 and maintains full technical support and manufacturing continuity for legacy Intersil power management ICs.

The ISL6534CRZ belongs to Intersil's high-density multi-rail PMIC product line, designed specifically for DDR memory subsystems and complex embedded systems requiring precise, sequenced, and thermally efficient voltage regulation.

FAQ

What is the function of the REFOUT pin on the ISL6534CRZ?

The REFOUT pin on the ISL6534CRZ provides a buffered copy of the REFIN voltage, commonly used as a VTT reference in DDR applications. It also serves a dual purpose: when tied to VCC, it selects 0° phase alignment between the two buck regulators; when left open, it enables 90° (DDR mode) or 180° (Independent mode) phase shift. In either configuration, REFOUT maintains ±10mV offset accuracy and supports 0.2–20mA sourcing.

Can the ISL6534CRZ operate without a 5V supply?

Yes, the ISL6534CRZ can operate with only a 12V supply using its internal shunt regulator. Connecting a 150Ω resistor from VCC to VCC12 generates a regulated 5.8V ±0.2V supply, eliminating the need for an external 5V rail. This configuration is explicitly supported in the datasheet and maintains full functionality-including PGOOD assertion, soft-start timing, and reference accuracy-across the 0°C–70°C temperature range.

How does the ISL6534CRZ support DDR memory voltage tracking?

The ISL6534CRZ supports DDR voltage tracking by configuring OUT2 to use VOUT1 as its reference: a resistor divider from VOUT1 to GND connects to REFIN, causing OUT2 to regulate at half VOUT1 (e.g., 1.8V → 0.9V VTT). This is enabled in DDR mode by tying SS2/EN2 to VCC. The buffered REFOUT pin then delivers a clean, low-impedance VTT reference, and 90° phase staggering minimizes input ripple current during memory bursts.

What thermal performance can be expected from the ISL6534CRZ in QFN-32 package?

The ISL6534CRZ in its 32-lead 5×5 mm QFN package achieves θJA = 32°C/W (typical) and θJC = 4°C/W when mounted on a standard 4-layer PCB with adequate copper pour under the exposed thermal pad. This allows continuous operation at full rated load up to 70°C ambient temperature. The GND-connected thermal pad must be soldered to a solid ground plane; thermal vias (≥6×0.3mm) are recommended to enhance heat transfer to inner layers.

Does the ISL6534CRZ provide protection against output short circuits?

Yes, the ISL6534CRZ includes short-circuit protection monitored at the COMP1 and COMP2 pins. If either COMP pin drops below 3.3V for more than 1–2 internal clock cycles (~3.3µs each at 300kHz), the device asserts PGOOD low and shuts down all three outputs. This fast detection-combined with independent soft-start and PGOOD sequencing-prevents damage during board bring-up or transient faults while maintaining system-level power integrity.