NXP Semiconductors PCF1252-1T/F4,112

Overview

PCF1252-1T/F4,112 from NXP Semiconductors (formerly Philips) is a low-power CMOS voltage threshold detector and reset generator designed for microcontroller/microprocessor power supervision. It features a factory-programmed 4.55 V trip voltage (±50 mV accuracy), 10 µA typical supply current, and dual-comparator architecture with RESET pulse delay controlled by external capacitor CT. It is used in embedded systems requiring reliable power-on reset and advance power-fail warning.

For engineers reviewing the PCF1252-1T/F4,112 datasheet, PCF1252-1T/F4,112 pinout, PCF1252-1T/F4,112 application, or PCF1252-1T/F4,112 equivalent, key selection considerations include its precise 4.55 V threshold, ±50 mV temperature-stable trip point, selectable RESET polarity via SELECT pin, POWF output for data retention timing, and dual-comparator capability enabling secondary voltage monitoring.

Technical Context

The PCF1252-1T/F4,112 integrates two independent comparators: Comparator 1 monitors VDD against a factory-trimmed internal reference to generate RESET and POWF signals; Comparator 2 accepts external input at COMIN with a fixed 1.30 V switch point for secondary monitoring (e.g., overvoltage). Its delay circuit uses an external capacitor on CT to set both reset pulse width (tR) and save time (tS).

RESET pulse polarity is selected via the SELECT pin (LOW = active-high RESET; HIGH = active-low), and POWF asserts LOW when VDD falls below the 4.55 V trip point. Hysteresis of 15–50 mV prevents oscillation near VTRIP, and the device operates across −40 °C to +85 °C with supply voltage range 2.4–6.0 V.

Key Specifications

Pinout & Package

PCF1252-1T/F4,112 is housed in an SO8 package (SOT96-1), plastic small outline, 8-lead, 3.9 mm body width, surface-mount compatible.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3808G01DBVR and MAX690EPA+, the PCF1252-1T/F4,112 uniquely delivers factory-trimmed 4.55 V supervision, user-adjustable timing via CT, POWF-driven data retention, and a second comparator - making it suitable for cost-sensitive, multi-rail industrial controllers where flexibility and deterministic shutdown behavior are essential.

Availability

PCF1252-1T/F4,112 is available at Aetrix Electronics and suitable for microcontroller power-on reset, data retention in backup memory systems, secondary overvoltage monitoring, and single-supply systems with external reset input requiring stable component supply across extended temperature and long-lifecycle programs.

Supply support for PCF1252-1T/F4,112 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

NXP Semiconductors is a global semiconductor company formed from the spin-off of Philips Semiconductors in 2006, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The PCF1252-X family was developed by Philips Semiconductors to address the need for low-cost, low-power, highly accurate voltage supervisors in microcontroller-based embedded systems - particularly those requiring deterministic reset timing and advance power-fail signaling for data integrity.

FAQ

What is the factory-programmed voltage trip point for PCF1252-1T/F4,112?

The PCF1252-1T/F4,112 has a factory-programmed voltage trip point of 4.55 V, with guaranteed accuracy of ±50 mV over the full industrial temperature range (−40 °C to +85 °C). This value is fixed per the "-1" suffix in the part number and is trimmed during manufacturing - no external components are needed to set the threshold.

How is the RESET pulse duration determined for PCF1252-1T/F4,112?

The RESET pulse duration (tR) of the PCF1252-1T/F4,112 is set by an external capacitor connected to the CT pin (Pin 1). With a 1 nF capacitor, tR ranges from 400 µs to 2000 µs. The relationship is approximately tR(typ.) = (0.1 + CCT) ms, allowing precise adjustment from ~100 µs to several milliseconds depending on capacitor value.

What function does the POWF output serve on PCF1252-1T/F4,112?

The POWF (Power Fail) output on the PCF1252-1T/F4,112 goes LOW when VDD falls below the 4.55 V trip point, providing advance warning of supply collapse. It initiates a defined save time (tS), which - like tR - is set by the CT capacitor. This gives the system a deterministic window (e.g., 40–200 µs with 1 nF) to store critical data before RESET asserts.

Can PCF1252-1T/F4,112 monitor a second voltage rail?

Yes. The PCF1252-1T/F4,112 includes a second comparator with COMIN (Pin 3) and COMOUT (Pin 5). COMIN accepts an external voltage; COMOUT switches HIGH when that voltage exceeds 1.30 V (±20 mV). Used with a resistive divider, this enables hardware-level monitoring of a secondary rail - such as a 12 V supply - without firmware involvement.

What is the purpose of the SELECT pin on PCF1252-1T/F4,112?

The SELECT pin (Pin 2) on the PCF1252-1T/F4,112 serves two functions: (1) it selects RESET polarity (LOW = active-high; HIGH = active-low), matching diverse MCU reset input requirements; and (2) when driven by a debounced external signal, it forces RESET assertion independently of VDD level - enabling manual reset or watchdog integration without additional logic.