Renesas ISL88022IU8FCZ

Overview

ISL88022IU8FCZ from Intersil is a triple voltage monitor IC with overvoltage detection on V3MON, fixed 3.09V VDD trip threshold, fixed 2.32V V2MON threshold, and 0.595V internal reference for adjustable OV monitoring - used in multi-rail embedded systems to assert active-low open-drain RST and active-high push-pull RST during supply faults.

For engineers reviewing the ISL88022IU8FCZ datasheet, ISL88022IU8FCZ pinout, ISL88022IU8FCZ application, or ISL88022IU8FCZ equivalent, this device supports precise overvoltage supervision of auxiliary rails (e.g., 3.3V), customizable POR timeout via CPOR capacitor, manual reset debouncing, and operation down to VDD = 1V - critical for reliable boot sequencing in industrial controllers and portable equipment.

Technical Context

The ISL88022IU8FCZ implements independent voltage comparators for VDD (3.09V ±0.056V), V2MON (2.32V ±0.042V), and V3MON referenced to a 0.595V internal bandgap. It asserts reset when VDD or V2MON falls below their thresholds or when V3MON exceeds its threshold - confirming true overvoltage detection behavior per datasheet Figure 1 and ordering table.

Its POR circuit activates at VDD > 1V and holds RST low for ≥140ms (tPOR) with open CPOR; timing extends linearly with external capacitance up to 50pF. Both RST (open-drain) and RST (push-pull) outputs are simultaneously controlled by the same internal logic state, enabling flexible interface to microcontrollers or FPGAs.

Key Specifications

Pinout & Package

Package: 8-lead MSOP (Mini Small Outline Plastic), 3.0mm × 3.0mm body, 0.65mm 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 ISL88022IU8FCZ, ISL88022IU8FEZ offers higher V2MON threshold for 3.3V rail supervision but identical OV functionality and timing control, while MAX6816EUK+T sacrifices channel count, flexibility, and overvoltage detection to reduce footprint and cost - making it unsuitable as a drop-in replacement.

Availability

ISL88022IU8FCZ is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical monitors, multi-rail FPGA development boards, smart energy meters, and battery-powered instrumentation requiring stable component supply across extended temperature ranges.

Supply support for ISL88022IU8FCZ 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) designs high-performance analog and mixed-signal ICs for power management, precision analog, and interface applications.

The ISL88022IU8FCZ belongs to Intersil's voltage supervisor product line, engineered specifically for robust, multi-rail power integrity monitoring in industrial, medical, and communications equipment with strict reliability and timing requirements.

FAQ

What is the V3MON overvoltage threshold configuration for ISL88022IU8FCZ?

The ISL88022IU8FCZ uses an internal 0.595V reference to compare against a resistor-divided version of the monitored rail on V3MON. When the divided voltage exceeds 0.595V, the device asserts reset - enabling precise overvoltage detection. For example, a 3.3V rail with a 5.5:1 divider yields 0.6V at V3MON, triggering reset if the rail rises above ~3.33V. This configuration is confirmed in the FN8226 datasheet Section "Functional Description" and ordering table.

Does ISL88022IU8FCZ support undervoltage detection on V3MON?

No. The ISL88022IU8FCZ is specifically designated as an overvoltage monitor on V3MON, as indicated by "OV" in the ordering table row for ISL88022IU8FCZ and clarified in the datasheet: "The ISL88021 V3MON input monitors for undervoltage (UV) conditions whereas the ISL88022 V3MON input allows monitoring for overvoltage (OV) conditions." Using it for UV would violate its specified function and timing behavior.

What is the minimum VDD voltage at which ISL88022IU8FCZ guarantees reset assertion?

The ISL88022IU8FCZ guarantees valid reset signaling down to VDD = 1V, as stated in the datasheet: "Reset Signal Valid to VDD = 1V." Below this, internal comparators and output drivers may not operate reliably. This enables use in brownout scenarios where main supply dips but does not fully collapse - critical for graceful shutdown in battery-backed systems.

Can ISL88022IU8FCZ be used with a 5V VDD supply?

Yes. The ISL88022IU8FCZ supports VDD from 2.0V to 5.5V per Absolute Maximum Ratings and Electrical Specifications. Its VDD trip threshold is fixed at 3.09V, so with a 5V supply, it will assert reset only if VDD drops below 3.09V - making it suitable for supervising 3.3V-regulated rails derived from 5V sources, not the raw 5V input itself unless regulation fails.

How does the CPOR capacitor affect the power-on-reset timeout of ISL88022IU8FCZ?

A capacitor between CPOR and GND linearly increases the tPOR delay beyond the base 140–200ms range. Per Figure 2 in FN8226, a 10pF capacitor extends tPOR to ~175ms (normalized), and maximum recommended value is 50pF. Stray capacitance must be minimized in layout, as it contributes directly to timing error - verified by test data showing tPOR = 150ms with CPOR open in Figure 5.