onsemi CAT1161LI-30

Overview

CAT1161LI-30 from Catalyst Semiconductor is a supervisory IC integrating 16 Kb I²C EEPROM, precision reset controller with 3.00–3.15 V threshold, watchdog timer (1.6 s timeout), and hardware write protection. It operates from 2.7 V to 6.0 V, supports 400 kHz I²C bus, and delivers active-high/active-low reset outputs for microcontroller power-up/brownout supervision in embedded industrial systems.

For engineers reviewing the CAT1161LI-30 datasheet, pinout, applications, or equivalent options, this device serves as an integrated memory + reset + watchdog solution requiring no external SDA monitoring trace, offering verified 1,000,000 write cycles, 100-year data retention, and dual-reset I/O capability for robust system recovery in 3V microcontroller platforms.

Technical Context

The CAT1161LI-30 implements a dedicated SDA-line watchdog that triggers reset after 1.6 seconds of inactivity-eliminating need for separate timing circuitry. Its reset controller features open-drain active-high RESET and active-low RESET̅ outputs with 200 ms timeout after VCC exceeds 3.00 V, plus glitch rejection (100 ns) and 15 mV hysteresis.

EEPROM operation uses standard I²C protocol with 16-byte page write buffer, ACK polling support, and hardware protection via WP pin and VCC lockout below reset threshold. Memory access remains disabled during reset assertion, ensuring data integrity during power transients.

Key Specifications

Pinout & Package

Package: 8-pin PDIP (0.300" wide), JEDEC MS-001 compliant, industrial temperature range (–40 °C to +85 °C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361KA30+T and MCP79410-I/SN, CAT1161LI-30 uniquely combines 16 Kb EEPROM, 3.00–3.15 V precision reset, and SDA-line watchdog in one 8-pin package-reducing component count, PCB area, and qualification effort for 3V industrial controllers.

Availability

CAT1161LI-30 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, smart energy meters, medical handheld diagnostics, factory HMI panels, and embedded telemetry gateways requiring stable component supply with long lifecycle assurance.

Supply support for CAT1161LI-30 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

Catalyst Semiconductor was a fabless analog/mixed-signal IC designer focused on power management, memory, and supervisory solutions before acquisition by ON Semiconductor in 2010.

The CAT1161LI-30 belongs to Catalyst's supervisory memory family, engineered to replace discrete reset ICs + EEPROM combinations in cost-sensitive, space-constrained microcontroller systems operating at 3V and 5V rails.

FAQ

What is the exact reset threshold voltage range for CAT1161LI-30?

The CAT1161LI-30 has a guaranteed reset threshold range of 3.00 V to 3.15 V at VCC = 3.3 V, with 15 mV hysteresis. This matches 3.3 V system brownout requirements and ensures reliable reset assertion during voltage sags. The threshold is factory-trimmed and specified across the full industrial temperature range (–40 °C to +85 °C). CAT1161LI-30 maintains this accuracy without external components.

Does CAT1161LI-30 require an external pull-up resistor on the SDA line?

Yes, CAT1161LI-30 requires an external pull-up resistor on the SDA line because its SDA pin is open-drain. A typical value is 4.7 kΩ to VCC, ensuring proper I²C signaling at up to 400 kHz. The same pull-up enables the SDA-monitored watchdog function-without it, the watchdog cannot detect inactivity and will not trigger reset. CAT1161LI-30 relies on this external bias for both communication and supervision.

Can CAT1161LI-30 be used in a 5 V system?

Yes, CAT1161LI-30 supports 2.7 V to 6.0 V operation, making it fully compatible with 5 V systems. However, its reset threshold is fixed at 3.00–3.15 V-so in a 5 V design, it monitors for brownout relative to 3 V, not 5 V. For 5 V-specific reset, use CAT1161LI-45 (4.50–4.75 V threshold). CAT1161LI-30 remains valid for mixed-voltage systems where 3 V logic coexists with 5 V peripherals.

How does the manual reset function work on CAT1161LI-30?

CAT1161LI-30 supports manual reset via either RESET (low-to-high edge) or RESET̅ (high-to-low edge). An internal 200 ms timer debounces the input and holds the complementary reset output active for that duration. During manual reset assertion, EEPROM access is disabled-preventing corruption. CAT1161LI-30 treats manual and power-on resets identically in terms of memory protection and timing behavior.

Is the EEPROM in CAT1161LI-30 write-protected by default?

No, the EEPROM in CAT1161LI-30 is not write-protected by default. Protection requires tying the WP pin to VCC. When WP = VCC, the entire 16 Kb array becomes read-only; when WP = GND or floating, full read/write access is enabled. VCC lockout provides additional protection-writes are inhibited whenever VCC falls below 3.00 V or hasn't yet risen above it during power-up. CAT1161LI-30 enforces both mechanisms simultaneously when active.