Renesas ISL6528CB

Overview

ISL6528CB from Intersil is a dual-output power controller integrating a standard buck PWM regulator (for high-current GPU supply) and a linear regulator (for lower-current memory supply), both delivering ±2% static regulation over line, load, and temperature. It operates at 600kHz fixed frequency, supports 0.8V–3.3V adjustable outputs via external resistors, and uses a single 5V bias supply in an 8-lead SOIC package for graphics card and embedded processor applications.

For engineers reviewing the ISL6528CB datasheet, ISL6528CB pinout, ISL6528CB application, or ISL6528CB equivalent, key selection considerations include dual-regulator topology compatibility, 600kHz switching frequency alignment with board-level timing constraints, ±2% output accuracy under thermal stress, and SOIC-8 footprint integration with existing GPU power delivery layouts.

Technical Context

The ISL6528CB implements voltage-mode PWM control for its buck channel-featuring a high-bandwidth error amplifier (15MHz GBWP), full 0–100% duty cycle capability, and fast transient response-while its linear channel employs bipolar NPN pass transistor drive via DRIVE2 with independent undervoltage monitoring on FB2. Both regulators share a common soft-start ramp and shutdown logic triggered by either FB or FB2 falling below 52.5% of the 0.8V internal reference.

It integrates oscillator (550–650kHz), POR (4.4V rising threshold), and fault logic that forces simultaneous shutdown on UV events, followed by hiccup-mode recovery with 10.5ms delay between soft-start attempts. The BOOT/UGATE bootstrap gate driver supports N-channel MOSFETs with ≤5Ω source/sink impedance and requires external 0.47μF bootstrap capacitance referenced to PHASE.

Key Specifications

Pinout & Package

ISL6528CB is housed in an 8-lead SOIC package (M8.15 drawing), surface-mount, Pb-free compatible, with 0°C to 70°C operating temperature range. Thermal resistance θ_JA = 110°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output power controller applications.

Compared with ISL6528CB, ISL6523CRZ offers tighter regulation and smaller footprint but removes linear regulation entirely, while RT8105DGQW provides enhanced driver strength yet omits the critical linear control path and coordinated fault response needed for memory-supply integrity.

Availability

ISL6528CB is available at Aetrix Electronics and suitable for graphics card GPU supplies, ASIC core power delivery, and embedded processor I/O rail generation requiring stable component supply across extended production cycles.

Supply support for ISL6528CB 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

Intersil (now part of Renesas Electronics) is a semiconductor company specializing in precision analog and power management ICs for computing, communications, and industrial markets.

The ISL6528CB belongs to Intersil's graphics power controller product line, designed specifically to integrate GPU and memory rail regulation into a single SOIC package for cost- and space-sensitive add-in cards.

FAQ

What is the maximum junction temperature specification for the ISL6528CB?

The ISL6528CB has a maximum junction temperature of 150°C, with a specified operating ambient temperature range of 0°C to 70°C. Its SOIC package exhibits a typical thermal resistance θ_JA of 110°C/W, meaning proper PCB copper pour and thermal vias are essential to maintain safe junction temperatures under full load. Derating curves in the FN9038 datasheet confirm sustained operation up to 125°C junction under defined airflow and layout conditions.

Does the ISL6528CB support both buck and linear regulation simultaneously?

Yes, the ISL6528CB is explicitly designed to operate both regulation channels concurrently: the buck PWM controller manages VOUT1 (e.g., GPU core) via UGATE and FB, while the linear controller manages VOUT2 (e.g., memory) via DRIVE2 and FB2. Both rails share the same soft-start ramp and are shut down together upon any UV fault - confirmed in the block diagram and functional description on pages 2–3 of FN9038 Rev 4.00.

Can the ISL6528CB be used with a 3.3V input supply for the upper MOSFET drain?

Yes, the ISL6528CB is rated for a +3.3V supply to the drain of the upper MOSFET, as stated in the "Operating Conditions" table on page 4 of FN9038 Rev 4.00. The BOOT pin's absolute maximum voltage is limited to 10V, which is safely met with 5V VCC and 3.3V drain - making it compatible with standard 3.3V-input graphics card power architectures.

What is the purpose of the FB2 pin on the ISL6528CB beyond feedback?

On the ISL6528CB, the FB2 pin serves dual functions: it provides feedback for the linear regulator output voltage and acts as an active shutdown input. Pulling FB2 above 1.28V (typical) forces immediate shutdown of both regulators; releasing it initiates a full soft-start sequence. This dual role is documented in the "Functional Pin Descriptions" section (page 5) and Figure 2 (UV protection response) of FN9038 Rev 4.00.

Is the ISL6528CB RoHS compliant and lead-free?

Yes, the ISL6528CB is RoHS compliant and offered in a Pb-free version (ISL6528CBZ). Per the "Ordering Information" table and footnote on page 1 of FN9038 Rev 4.00, the Pb-free variant uses 100% matte tin plating and meets IPC/JEDEC J-STD-020 reflow profiles - fully compatible with both SnPb and lead-free soldering processes.