Renesas ISL6532CRZ

Overview

ISL6532CRZ from Renesas Electronics (formerly Intersil) is an ACPI-compliant dual-rail power controller for DDR/DDR2 memory systems, integrating a 250kHz synchronous buck PWM controller for VDDQ (adjustable down to 0.8V), a 3A sink-source VTT linear regulator with precise VDDQ/2 reference, and a buffered VREF_OUT. It delivers ±2% static regulation over line/load/temperature and enables glitch-free S0/S3/S5 state transitions in ATX-based PCs and graphics cards.

For engineers reviewing the ISL6532CRZ datasheet, ISL6532CRZ pinout, ISL6532CRZ application, or ISL6532CRZ equivalent, key selection considerations include its integrated NCH backfeed control logic, dual-input support (5VSBY or 3.3VSBY for standby VDDQ), thermal shutdown at 140°C, PGOOD monitoring of both VDDQ and VTT rails, and QFN-20 package compatibility with DDR2 termination requirements.

Technical Context

The ISL6532CRZ implements voltage-mode PWM control with 250kHz fixed-frequency operation, fast transient response, and internal soft-start timing (6.5–9.5ms). Its dual-regulator architecture separates VDDQ generation (synchronous buck) from VTT generation (integrated sink-source LDO), with independent under/over-voltage protection (85–115% thresholds) and adaptive shoot-through protection on UGATE/LGATE.

ACPI state management is hardware-driven via dedicated S3# and S5# inputs, enabling automatic switching between PWM and standby LDO modes without external sequencing. The NCH open-drain output synchronizes backfeed MOSFET control during sleep transitions, while VREF_IN capacitor sets VTT soft-start ramp time based on RU||RL divider network.

Key Specifications

Pinout & Package

ISL6532CRZ is housed in a Pb-free, JEDEC MO-220 compliant 20-lead 6×6 mm QFN package with exposed thermal pad (Pin 21). The package supports high-density DDR memory power delivery and efficient heat dissipation via direct ground-plane connection through ≥4 vias.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DDR memory power controller applications.

Compared with ISL6532CRZ, ISL6537CRZ provides higher VTT current and VPP support in identical packaging, while RT8205AZSP integrates more rails but replaces hardware ACPI logic with software-managed sequencing-making ISL6532CRZ the preferred choice for legacy DDR2 systems requiring deterministic, low-latency state transitions.

Availability

ISL6532CRZ is available at Aetrix Electronics and suitable for desktop motherboards, graphics cards, ASIC memory interfaces, and embedded DDR2 systems requiring stable component supply, long-term lifecycle support, and Pb-free compliance.

Supply support for ISL6532CRZ 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 and manufacturing continuity for legacy Intersil power management products.

The ISL6532CRZ belongs to Intersil's ACPI-compliant memory power controller family, designed specifically for DDR/DDR2 memory subsystems in PC, graphics, and embedded computing platforms where deterministic power-state transitions and tight voltage regulation are critical.

FAQ

What is the primary function of the ISL6532CRZ in a DDR memory system?

The ISL6532CRZ serves as a complete ACPI-compliant power controller for DDR/DDR2 memory, generating and regulating both the VDDQ core voltage (via synchronous buck PWM) and the VTT termination voltage (via integrated sink-source LDO). It manages seamless transitions between S0, S3, and S5 states using dedicated S3# and S5# inputs, and provides buffered VREF_OUT for system-level reference distribution. This functionality is fully implemented in the ISL6532CRZ without requiring external sequencing logic.

Does the ISL6532CRZ support both 5VSBY and 3.3VSBY inputs for standby VDDQ operation?

Yes, the ISL6532CRZ supports either 5VSBY or 3.3VSBY on the P5VSBY pin to power the integrated standby LDO during S3 state. When supplied from 5VSBY, the LDO delivers up to 650 mA; from 3.3VSBY, it delivers up to 550 mA. This dual-input flexibility allows the ISL6532CRZ to operate across ATX power supplies with varying standby rail configurations without redesigning the power stage.

How does the NCH pin function in the ISL6532CRZ, and what external component is required?

The NCH pin on the ISL6532CRZ is an open-drain output that controls the backfeed-blocking MOSFET during sleep transitions. It must be externally pulled up to the 12V rail using a resistor ≥2 kΩ. The ISL6532CRZ holds NCH low until the P12V rail exceeds 9.5 V, preventing premature PWM activation. If unused, NCH still requires this pull-up; adding a capacitor to the NCH node can delay PWM start-up in 5V-dual input configurations. This behavior is intrinsic to the ISL6532CRZ's hardware state machine.

What is the maximum VTT load current supported by the ISL6532CRZ, and how is it measured?

The ISL6532CRZ supports a maximum VTT load current of ±3 A, measured under periodic loading conditions (30% duty cycle, 10 ms period) using the ISL6532EVAL1 evaluation board per Application Note AN1055. This rating reflects the device's ability to both source and sink current simultaneously-critical for DDR memory I/O bus termination-and is validated at the VTTSNS feedback node. The ISL6532CRZ achieves this with no external components beyond the recommended RU/RL divider network.

Is the ISL6532CRZ pin-compatible with any newer Renesas alternatives for DDR2-to-DDR3 migration?

No, the ISL6532CRZ is not pin-compatible with DDR3-targeted successors like the ISL6537CRZ, despite sharing the same 20-pin QFN package and footprint. While ISL6537CRZ retains identical pin assignments for power, ground, and control signals, its enhanced VTT current (±4 A) and added VPP rail require updated layout for decoupling and thermal management. Migration from ISL6532CRZ to ISL6537CRZ necessitates validation of VTT loop stability and VPP sequencing-not just drop-in replacement-due to differences in internal protection thresholds and startup timing.