Renesas ISL6840IBZ

Overview

ISL6840IBZ from Renesas Electronics is a single-ended current mode PWM controller designed for boost, flyback, and isolated buck regulators. It delivers 1A peak gate drive, supports up to 2MHz switching frequency, features 60µA start-up current, and provides 100% maximum duty cycle with 7.0V UVLO rising threshold. It operates across –40°C to +105°C in telecom power supplies.

For engineers reviewing the ISL6840IBZ datasheet, ISL6840IBZ pinout, ISL6840IBZ application, or ISL6840IBZ equivalent, key selection criteria include UVLO threshold (7.0V), duty cycle capability (100%), gate drive strength (1A), propagation delay (25ns), and SOIC-8 package compatibility with industry-standard 384x controllers.

Technical Context

The ISL6840IBZ implements peak current mode control with a high-bandwidth error amplifier and trimmed timing capacitor discharge for precise deadtime and maximum duty cycle regulation. Its oscillator generates a programmable sawtooth waveform up to 2MHz using external RT/CT components.

It integrates a 5.00V ±1.0%/–1.5% reference with 25ns CS-to-OUT propagation delay, 20ns rise/fall times into 1nF load, and tight current limit threshold tolerance. The device disables output when VREF falls below 4.65V and re-enables at 4.80V.

Key Specifications

Pinout & Package

ISL6840IBZ is housed in an 8-lead narrow-body SOIC package (M8.15), RoHS-compliant, rated for –40°C to +105°C operation. Thermal resistance θ_JA = 100°C/W (SOIC).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PWM controller applications.

Compared with UCC2800DTR and TL3845P, ISL6840IBZ offers superior gate drive (1A vs ≤500mA), wider frequency range (up to 2MHz vs ≤1MHz), and integrated 5V reference-enabling higher efficiency, smaller magnetics, and simplified feedback design in modern telecom and industrial SMPS.

Availability

ISL6840IBZ is available at Aetrix Electronics and suitable for telecom power supplies, industrial DC-DC converters, and PC power supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for ISL6840IBZ 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 ISL6840IBZ belongs to Renesas' high-performance PWM controller product line, engineered specifically for efficient, reliable, and compact AC-DC and DC-DC power conversion in demanding infrastructure and computing environments.

FAQ

What is the UVLO rising threshold voltage for ISL6840IBZ?

The ISL6840IBZ has a UVLO rising threshold of 7.0V, with ±0.5V tolerance. This ensures reliable startup only when the VDD supply reaches a stable operating level, preventing erratic behavior during brown-out conditions. The corresponding stop threshold is 6.6V, providing 0.4V hysteresis to avoid oscillation near the trip point. This specification is confirmed in the Electrical Specifications table on page 8 of FN9124 Rev.14.00.

Does ISL6840IBZ support 100% duty cycle operation?

Yes, ISL6840IBZ supports up to 100% maximum duty cycle, as explicitly stated in the datasheet's part number table on page 1. This capability is essential for flyback and isolated buck topologies requiring extended on-time for transformer reset or high step-down ratios. It distinguishes ISL6840IBZ from variants like ISL6841IBZ (50% max duty), and is enabled by its internal timing architecture and RTCT discharge control.

What package type is used for ISL6840IBZ?

ISL6840IBZ uses an 8-lead narrow-body SOIC package (package drawing M8.15), with lead pitch of 1.27mm and body dimensions 4.9mm × 3.9mm. It is Pb-free and RoHS-compliant, rated for operation from –40°C to +105°C. The package outline is detailed on page 14 of FN9124 Rev.14.00, and thermal resistance θ_JA is specified as 100°C/W under standard test conditions.

Can ISL6840IBZ replace UC3842 in existing designs?

Yes, ISL6840IBZ is pin-compatible with the industry-standard UC384x family and offers enhanced performance-including 1A gate drive (vs 200mA), 2MHz frequency (vs 500kHz), and 60µA start-up current (vs 1mA). However, designers must verify UVLO thresholds (7.0V vs 16V), VREF output (5.00V vs none), and maximum duty cycle (100% vs 50%) to ensure functional equivalence in the target application.

What is the typical propagation delay from CS to OUT in ISL6840IBZ?

The typical CS-to-OUT propagation delay for ISL6840IBZ is 25ns, with a maximum of 40ns across temperature and process variation. This low latency enables fast cycle-by-cycle current limiting, critical for protecting power switches during overload or short-circuit events. The value is specified in the Electrical Specifications table on page 8 of FN9124 Rev.14.00 under "CS to OUT Delay".