Renesas ISL88021IU8HEZ

Overview

ISL88021IU8HEZ from Intersil is a triple voltage monitor IC with adjustable power-on-reset, undervoltage monitoring on VDD (4.64V threshold), V2MON (2.92V fixed), and V3MON (0.605V internal reference for UV detection), designed for system-level power integrity in embedded controllers. It provides both active-low open-drain RST and active-high push-pull RST outputs, operates from 2.0V to 5.5V supply, and consumes only 15µA typical current.

For engineers reviewing the ISL88021IU8HEZ datasheet, ISL88021IU8HEZ pinout, ISL88021IU8HEZ application, or ISL88021IU8HEZ equivalent, key selection considerations include its 4.64V/2.92V dual-fixed UV thresholds, 0.605V adjustable V3MON reference, 140–200ms POR timeout (capacitor-adjustable), -40°C to +85°C industrial temperature range, and 8-lead MSOP package compatibility with multi-rail power supervision designs.

Technical Context

The ISL88021IU8HEZ implements independent comparator-based monitoring of three voltage rails: VDD (fixed 4.64V trip with 46mV hysteresis), V2MON (fixed 2.92V trip with 29mV hysteresis), and V3MON (UV detection referenced to 0.605V ±11mV). All comparators drive a shared reset state machine that asserts both RST and RST outputs when any monitored rail violates its threshold.

Power-On-Reset timing is controlled by an internal counter gated by CPOR pin capacitance - nominal tPOR is 140–200ms with CPOR open, scalable up to ~390ms with 10pF, and limited to ≤50pF maximum. The MR input features 20kΩ internal pull-up and 550ns minimum pulse width, enabling robust manual reset with debounced push-button interface.

Key Specifications

Pinout & Package

Package: 8-lead MSOP (Mini Small Outline Plastic), 3.0mm × 3.0mm body, 0.65mm lead pitch, RoHS-compliant Pb-free plus anneal finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple voltage monitoring applications.

Compared with MAX6326US29D3+ and TPS3808G33DBVR, the ISL88021IU8HEZ uniquely delivers three independent voltage monitoring channels with factory-set 4.64V/2.92V thresholds and a 0.605V-referenced adjustable input - enabling compact, high-integrity supervision of complex multi-rail embedded systems without external comparators or timing components.

Availability

ISL88021IU8HEZ is available at Aetrix Electronics and suitable for industrial process controllers, embedded computer systems, and portable test instruments requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for ISL88021IU8HEZ 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 Corporation (now part of Renesas Electronics) is a U.S.-based analog and power management IC designer known for high-reliability supervisors, PMICs, and precision analog products.

The ISL88021IU8HEZ belongs to Intersil's triple voltage monitor family, engineered specifically for robust power integrity assurance in industrial, computing, and portable equipment where simultaneous multi-rail supervision and configurable reset timing are essential.

FAQ

What is the VDD undervoltage threshold for ISL88021IU8HEZ?

The ISL88021IU8HEZ has a fixed VDD undervoltage threshold of 4.649V (typical), with a guaranteed range of 4.565V to 4.733V across -40°C to +85°C. This threshold is factory-trimmed and includes 46mV hysteresis to prevent chatter during voltage recovery. The ISL88021IU8HEZ uses this trip point to assert reset when the main 5V supply sags below specification, ensuring safe microprocessor operation.

How does the V3MON pin function on ISL88021IU8HEZ?

On the ISL88021IU8HEZ, the V3MON pin monitors for undervoltage conditions by comparing an external voltage-scaled via a resistor divider-to an internal 0.605V reference. The ISL88021IU8HEZ asserts reset if the divided voltage falls below this reference. This enables customizable UV detection for rails such as 2.5V, 3.3V, or 5V without changing the IC, and is distinct from the ISL88022 variant which supports overvoltage monitoring on V3MON.

Can ISL88021IU8HEZ be used with a 3.3V-only system?

Yes, the ISL88021IU8HEZ supports 3.3V-only systems: its VDD supply range is 2.0V to 5.5V, and its V2MON input is factory-set to 2.92V - ideal for supervising a 3.3V rail. The V3MON pin can be configured (using a resistor divider) to monitor the same 3.3V rail for tighter UV margins or a secondary rail. Its 15µA quiescent current and -40°C to +85°C rating make it suitable for industrial 3.3V embedded designs.

What is the purpose of the CPOR pin on ISL88021IU8HEZ?

The CPOR pin on ISL88021IU8HEZ sets the Power-On-Reset timeout delay by connecting an external capacitor to ground. With CPOR open, tPOR is 140–200ms; adding capacitance scales this linearly - e.g., 10pF extends it to ~390ms. This allows designers to match reset timing to slow-ramping supplies or FPGA configuration clocks. The ISL88021IU8HEZ specifies a maximum 50pF CPOR capacitance to maintain accuracy and avoid excessive stray coupling.

Does ISL88021IU8HEZ provide both active-high and active-low reset outputs?

Yes, the ISL88021IU8HEZ provides two complementary reset outputs: RST is an active-low open-drain output requiring an external pull-up, and RST is an active-high push-pull output that drives high without external components. This dual-output architecture simplifies interface to diverse microcontrollers - for example, RST can drive ARM Cortex-M /RESET pins while RST feeds status LEDs or FPGA configuration enable signals - all from a single ISL88021IU8HEZ device.