onsemi CAT1023WI-42-GT3

Overview

CAT1023WI-42-GT3 from onsemi is a supervisory circuit with integrated 2 kbit I²C EEPROM, precision V_CC monitor (4.25 V–4.50 V threshold), dual open-drain reset outputs (active-high and active-low), and dedicated watchdog timer interrupt input (WDI). It operates from 2.7 V to 5.5 V, supports 400 kHz I²C communication, and delivers reliable power-up/down and brownout protection for microcontroller-based industrial systems.

For engineers reviewing the CAT1023WI-42-GT3 datasheet, pinout, applications, or equivalent options, this device is selected for embedded systems requiring concurrent memory storage, deterministic reset timing (200 ms timeout), glitch-immune manual reset (MR), hardware write protection via V_CC sensing, and independent watchdog supervision not tied to SDA activity.

Technical Context

The CAT1023WI-42-GT3 integrates a precision bandgap-based voltage comparator for V_CC monitoring, dual reset latches with guaranteed valid output down to V_CC = 1.0 V, and a 1.6-second watchdog timer cleared exclusively by transitions on the dedicated WDI pin - decoupling supervision from I²C bus activity. Its EEPROM uses a 16-byte page buffer and features built-in V_CC-sensed write inhibition during power transients.

Reset assertion is synchronized to V_CC crossing the 4.25 V–4.50 V threshold with 15 mV hysteresis; power-up reset timeout is 130–270 ms; MR input provides debounced, edge-triggered manual reset with 100 ns glitch immunity and 5 µs minimum pulse width. All logic interfaces comply with I²C standard-mode timing and 0.3×/0.7× V_CC input thresholds.

Key Specifications

Pinout & Package

Package: 8-pin SOIC (Case 751BD), 3.9 mm × 4.9 mm body, 1.27 mm pitch, 1.75 mm max height, RoHS-compliant NiPdAu finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar supervisory + EEPROM applications.

Compared with MAX6361KA29+T and STM8T142M2C, CAT1023WI-42-GT3 uniquely delivers simultaneous active-high/low reset signaling and hardware-decoupled watchdog supervision via WDI - eliminating design compromises in safety-critical or mixed-voltage microcontroller systems.

Availability

CAT1023WI-42-GT3 is available at Aetrix Electronics and suitable for industrial PLCs, medical sensor hubs, automotive body control units, and smart energy meters requiring stable component supply, long-term data integrity, and deterministic power supervision.

Supply support for CAT1023WI-42-GT3 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient silicon solutions for automotive, industrial, cloud, and medical applications.

CAT1023WI-42-GT3 belongs to the CAT102x family of supervisory circuits with integrated EEPROM, designed specifically for microcontroller-based systems needing concurrent power monitoring, nonvolatile storage, and fail-safe reset generation in space-constrained industrial designs.

FAQ

What is the exact reset threshold voltage range for CAT1023WI-42-GT3?

The CAT1023WI-42-GT3 has a guaranteed reset threshold range of 4.25 V to 4.50 V, specified at V_CC = 5.0 V. This range ensures reliable detection of brownout conditions in 5 V systems while providing sufficient hysteresis (15 mV) to prevent chatter during slow voltage recovery. The device remains fully functional across its 2.7 V–5.5 V supply range, and reset outputs are guaranteed valid down to V_CC = 1.0 V.

How does the WDI pin on CAT1023WI-42-GT3 differ from watchdog monitoring on CAT1021/CAT1022?

Unlike CAT1021 and CAT1022 - which monitor the SDA line for activity - the CAT1023WI-42-GT3 uses a dedicated WDI pin for watchdog supervision. This allows the watchdog timer to be cleared independently of I²C bus traffic, preventing false timeouts during EEPROM read/write operations or bus arbitration delays. Any high-to-low or low-to-high transition on WDI resets the 1.6 s timeout, making CAT1023WI-42-GT3 ideal for systems where SDA may be idle for extended periods without indicating failure.

Does CAT1023WI-42-GT3 support page writes to its EEPROM, and what is the page size?

Yes, CAT1023WI-42-GT3 supports page writes to its 2 kbit (256-byte) EEPROM with a 16-byte page buffer. A single I²C transaction can write up to 16 contiguous bytes, significantly reducing bus overhead compared to byte-wise writes. After sending the start condition, slave address, and first byte address, the host may transmit up to 15 additional bytes before issuing the stop condition; the device auto-increments the address counter and initiates internal programming upon stop detection.

Can CAT1023WI-42-GT3 be used in systems with both 3.3 V and 5 V logic domains?

Yes, CAT1023WI-42-GT3 operates from 2.7 V to 5.5 V and supports I²C communication across mixed-voltage systems. Its SDA and SCL inputs meet standard-mode I²C thresholds (V_IL ≤ 0.3×V_CC, V_IH ≥ 0.7×V_CC), and its open-drain outputs can be pulled to either 3.3 V or 5 V rails. The reset outputs are compatible with both logic families, and the MR input's internal pull-up ensures reliable triggering regardless of host voltage domain - provided appropriate level translation is used for bidirectional signals if needed.

Is hardware write protection available on CAT1023WI-42-GT3, and how does it work?

CAT1023WI-42-GT3 implements hardware write protection via V_CC sensing: whenever V_CC falls below the 4.25 V reset threshold - including during power-up ramp or brownout - all EEPROM write operations are automatically disabled. This prevents data corruption without requiring external control signals. Unlike CAT1021, CAT1023WI-42-GT3 does not include a dedicated WP pin; protection is fully intrinsic and tied to the monitored supply rail.