Texas Instruments TPS3610U18PW

Overview

TPS3610U18PW from Texas Instruments is a 1.8-V precision supervisory circuit with integrated backup-battery switchover, watchdog timer (800-ms timeout), power-fail comparator, and chip-enable gating. It monitors VDD for reset assertion at 1.71 V (typ), delivers up to 300 mA from VOUT, and supports manual battery switchover via MSWITCH - used in portable battery-powered equipment requiring data retention during brownout.

For engineers reviewing the TPS3610U18PW datasheet, TPS3610U18PW pinout, TPS3610U18PW application, or TPS3610U18PW equivalent, key selection considerations include its 1.71-V supply-voltage threshold, 40 µA max supply current, battery-freshness seal function, and dual-supply capability enabling CMOS RAM backup with 3.6-V lithium cells while operating from 1.8-V main rails.

Technical Context

The TPS3610U18PW implements a dual-path power-switching architecture: a 1-Ω (max) PMOS switch connects VDD to VOUT above reset threshold, while a 15-Ω switch enables VBAT-to-VOUT connection only when VDD falls below 1.71 V and VBAT exceeds VDD. Its internal 40-kΩ oscillator drives an 800-ms watchdog timer with transition-triggered reset.

It integrates five independent comparators: RESET supervisor (VIT = 1.71 V), BATTOK monitor (VBOK = 1.6 V), LOWLINE early warning (VLL ≈ VIT + 2%), PFI power-fail input (VIT = 1.15 V), and manual switchover control - all operating across –40°C to 85°C with hysteresis on each threshold.

Key Specifications

Pinout & Package

TPS3610U18PW is housed in a 14-pin TSSOP (PW) package, 5.10 mm × 6.60 mm, with exposed pad not present. Pin functions are validated per TI SLVS327B datasheet (Rev. December 2002).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar supervisory and battery-switchover applications.

Compared with TPS3610T50PW and MAX6361KA29+T, the TPS3610U18PW uniquely combines 1.8-V precision supervision, integrated battery switchover, and BATTOK monitoring in a single 14-pin TSSOP - eliminating need for external FETs, comparators, or discrete reset ICs in low-voltage portable designs.

Availability

TPS3610U18PW is available at Aetrix Electronics and suitable for portable battery-powered equipment, computer equipment, advanced modems, and automotive systems requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for TPS3610U18PW 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of experience in high-reliability supervisory ICs.

The TPS3610 family was designed specifically for systems requiring robust, integrated backup-battery management - combining reset, watchdog, power-fail detection, and chip-enable gating in one device for CMOS RAM data retention.

FAQ

What is the exact reset threshold voltage for TPS3610U18PW?

The TPS3610U18PW has a nominal supply-voltage threshold (VIT) of 1.71 V, with a guaranteed range of 1.68 V to 1.74 V over –40°C to 85°C. This value is factory-trimmed and specified in the electrical characteristics table of the SLVS327B datasheet. The threshold applies to both VDD and VBAT monitoring paths, and hysteresis is included to prevent chatter near the trip point. TPS3610U18PW uses this precise threshold to assert RESET before microcontroller operation becomes unreliable.

Does TPS3610U18PW support backup batteries with voltage higher than the main supply?

Yes, TPS3610U18PW explicitly supports VBAT > VDD configurations - such as a 3.6-V lithium coin cell backing a 1.8-V system rail. Its internal architecture isolates VBAT until VDD falls below 1.71 V, then engages a 15-Ω switch to connect VBAT to VOUT. The device also includes a battery-freshness seal that disconnects VBAT until first power-up, preserving shelf life. TPS3610U18PW does not require external level shifters or FETs for this functionality.

How does the watchdog timer in TPS3610U18PW operate, and what is its timeout period?

The TPS3610U18PW watchdog timer has a nominal timeout of 800 ms, with a guaranteed range of 480 ms to 1120 ms. It is edge-triggered: either a rising or falling transition on WDI resets the internal counter. If no transition occurs within the timeout window, RESET is asserted. During normal operation, firmware must toggle WDI at least once every 800 ms. TPS3610U18PW also includes a low-power optimization mode where WDI is held low for 7/8 of the period and pulsed briefly to minimize current draw.

What is the purpose of the LOWLINE output on TPS3610U18PW, and how is it configured?

The LOWLINE output on TPS3610U18PW provides early power-fail warning at approximately VIT + 2% (≈1.74 V for TPS3610U18PW), asserting ~10–50 ms before RESET activation. It is an open-drain output pulled to VDD during normal operation and driven low when VDD crosses the LOWLINE threshold. This signal is intended for nonmaskable interrupts (NMI) to initiate graceful shutdown routines. TPS3610U18PW does not require external components to configure LOWLINE - its threshold is internally fixed and temperature-compensated.

Can TPS3610U18PW be used to protect CMOS RAM from write corruption during power loss?

Yes, TPS3610U18PW prevents CMOS RAM write corruption through two integrated mechanisms: chip-enable (CE) gating and power sequencing. When RESET is asserted, the CEIN-to-CEOUT path is disabled, forcing CEOUT high-impedance or actively pulled to VOUT - blocking spurious memory writes. Simultaneously, VOUT switches from VDD to VBAT to maintain RAM supply. TPS3610U18PW guarantees CE propagation delay ≤5 ns at 5 V, ensuring timing-critical systems remain protected without additional logic.