Renesas ISL6844EVAL1Z

Overview

ISL6844EVAL1Z from Renesas Electronics is an evaluation board designed to demonstrate the ISL6844 single-ended current mode PWM controller in isolated flyback and boost converter applications. It supports adjustable switching frequency up to 2 MHz, features a 1A MOSFET gate driver, 25 ns CS-to-OUT propagation delay, and operates across –40°C to +105°C with UVLO thresholds of 14.3 V (ON) / 8.8 V (OFF).

For engineers reviewing the ISL6844EVAL1Z datasheet, ISL6844EVAL1Z pinout, ISL6844EVAL1Z application, or ISL6844EVAL1Z equivalent, this board enables rapid validation of peak current mode control loop stability, gate drive timing, duty cycle limits (47–48%), and VREF accuracy (±1.0/–1.5%) under real-world load transients and input voltage variations.

Technical Context

The ISL6844EVAL1Z implements the ISL6844 controller in a fully assembled, tested flyback reference design with external soft-start, slope compensation, and layout-optimized high-di/dt grounding. It leverages the IC's BiCMOS architecture for low start-up current (60 µA), fast transient response, and tight tolerance current limit threshold (100 mV ±5 mV).

Board-level functionality includes configurable RT/CT network for frequency tuning, COMP compensation network access points, isolated feedback via optocoupler, and direct measurement pads for CS, FB, OUT, and VREF signals - enabling precise characterization of oscillator linearity, error amplifier bandwidth, and fault recovery behavior (VREF fault at 4.65 V, clear at 4.80 V).

Key Specifications

Availability

ISL6844EVAL1Z is available at Aetrix Electronics and suitable for telecom power, industrial DC-DC converter development, and PC/server SMPS design requiring stable component supply and rapid prototyping support.

Supply support for ISL6844EVAL1Z 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 enterprise applications.

The ISL6844EVAL1Z belongs to Renesas' legacy high-performance PWM controller evaluation platform family, engineered specifically to accelerate adoption of current-mode controllers in cost-sensitive, high-reliability isolated power supplies.

FAQ

What is the primary function of the ISL6844EVAL1Z evaluation board?

The ISL6844EVAL1Z evaluation board is a fully assembled flyback reference design that demonstrates the ISL6844 current mode PWM controller. It enables engineers to validate key performance metrics including UVLO behavior (14.3 V ON / 8.8 V OFF), 47–48% maximum duty cycle operation, 25 ns CS-to-OUT timing, and VREF accuracy (5.000 V ±1.0/–1.5%) under real thermal and load conditions. The ISL6844EVAL1Z provides test points and configuration options for immediate loop analysis and system integration testing.

Does the ISL6844EVAL1Z support boost converter topologies?

Yes, the ISL6844EVAL1Z supports boost converter implementation using the same ISL6844 controller. While its default configuration is optimized for flyback operation, the board's accessible COMP, FB, CS, and RTCT pins allow reconfiguration for boost applications per Figure 2 in the ISL684x datasheet. External component changes - such as inductor placement, diode selection, and feedback divider - are required, but the ISL6844EVAL1Z's signal routing and grounding scheme remain applicable for evaluating gate drive strength, oscillator stability, and current sense accuracy in boost mode.

What are the UVLO thresholds programmed on the ISL6844EVAL1Z?

The ISL6844EVAL1Z implements the ISL6844 controller's native undervoltage lockout thresholds: 14.3 V (typical turn-on) and 8.8 V (typical turn-off), with 5.4 V hysteresis. These values are fixed by the ISL6844 silicon design and verified across –40°C to +105°C. No external resistor divider is used to modify UVLO; the ISL6844EVAL1Z delivers the exact thresholds specified in the ISL6844 datasheet, ensuring accurate validation of startup sequencing and brownout recovery behavior in target systems.

Can the ISL6844EVAL1Z be used to evaluate slope compensation?

Yes, the ISL6844EVAL1Z includes provisions for slope compensation per ISL684x functional description Section 4.5. A dedicated test point and series resistor location adjacent to the CS pin allow injection of programmable ramp signals, enabling empirical optimization of noise immunity - especially critical at light loads or >50% duty cycle operation. The board's layout preserves signal integrity for CS path routing, and the ISL6844EVAL1Z documentation references Figure 10 (slope compensation circuit) to guide implementation and measurement of compensation effectiveness on the actual hardware.

Is the ISL6844EVAL1Z still in active production and supported by Renesas?

The ISL6844EVAL1Z is listed as "No longer available or supported" in the official ISL684x ordering information (FN9124 Rev.14.00, Page 5). Renesas recommends ISL8844AABZ as the replacement controller IC, but no direct successor evaluation board is documented. Aetrix Electronics maintains limited legacy stock of ISL6844EVAL1Z for existing design continuity, with full technical documentation and schematic access provided. For new designs, migration guidance to ISL8844AABZ-based platforms is available upon request.