Texas Instruments TPS3617-50DGK

Overview

TPS3617-50DGK from Texas Instruments is a battery-backup supervisor IC designed for RAM retention in 5-V systems. It provides precision 4.55-V supply monitoring, active-low push-pull RESET with 100-ms power-on delay, watchdog timer with 800-ms timeout, and automatic VDD-to-VBAT switchover at VOUT. Used in set-top boxes and portable battery-powered equipment requiring nonvolatile data preservation during brownouts.

For engineers reviewing the TPS3617-50DGK datasheet, TPS3617-50DGK pinout, TPS3617-50DGK application, or TPS3617-50DGK equivalent, key selection considerations include its 40 µA max VDD supply current, 100 nA max battery supply current, 8-pin MSOP (DGK) package, battery freshness seal feature (TPS3617 only), and dual-voltage supervision capability (VDD and PFI).

Technical Context

The TPS3617-50DGK integrates a precision voltage monitor with 4.55-V threshold (±1.5% over temperature), a dedicated power-fail comparator (PFI/PFO) referenced to 1.15 V, and a watchdog timer that resets on any WDI transition within 0.8 s. Its internal switchover logic ensures VOUT connects to VBAT only when VDD falls below VIT and VBAT > VDD, with hysteresis of 60 mV on VIT and 12 mV on PFI.

It operates across –40°C to +85°C, supports VDD from 1.65 V to 5.5 V and VBAT from 1.5 V to 5.5 V, and delivers up to 300 mA continuous output current at VOUT with RDS(on) ≤1 Ω (VDD→VOUT) and ≤15 Ω (VBAT→VOUT). The device features a battery freshness seal-enabled via specific PFO/PFI/VDD sequencing-that isolates VBAT until first power-up.

Key Specifications

Pinout & Package

TPS3617-50DGK is housed in an 8-pin VSSOP (DGK) package, 3.05 mm × 4.98 mm footprint, 1.1 mm max height, with exposed thermal pad. Pin 1 index located at top-left corner per JEDEC MO-187.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery-backup supervisor applications.

Compared with TPS3617-50DGKR and MAX6361LKA29+T, the TPS3617-50DGK uniquely combines battery freshness sealing, dual-rail supervision, and integrated watchdog in an industry-standard 8-pin MSOP-enabling compact, reliable RAM retention without design compromises.

Availability

TPS3617-50DGK is available at Aetrix Electronics and suitable for set-top boxes, portable medical monitors, industrial PLCs, point-of-sale terminals, and advanced voice mail systems requiring stable component supply across long production lifecycles.

Supply support for TPS3617-50DGK 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, longevity, and industrial-grade performance.

The TPS3617 family was engineered specifically for battery-backed memory systems in consumer and industrial electronics, prioritizing ultra-low IBAT, precise VIT stability over temperature, and seamless VDD/VBAT switchover without external FETs or controllers.

FAQ

What is the function of the battery freshness seal in the TPS3617-50DGK?

The battery freshness seal in the TPS3617-50DGK physically isolates the VBAT pin from internal circuitry until first application of VDD, preventing premature discharge of the backup battery during storage or assembly. This ensures full capacity remains available at end-product deployment. The seal is disabled automatically by the rising edge of RESET during initial power-up, and is exclusive to the TPS3617 variant-not present in TPS3618-50DGK. The TPS3617-50DGK implements this via internal fuse-like control activated by a specific PFO grounding and PFI–VDD sequence.

How does the TPS3617-50DGK handle switchover between VDD and VBAT?

The TPS3617-50DGK switches VOUT from VDD to VBAT when VDD falls below 4.55 V and VBAT exceeds VDD, using internal PMOS switches with RDS(on) ≤1 Ω (VDD→VOUT) and ≤15 Ω (VBAT→VOUT). Recovery occurs immediately when VDD rises above VIT, with no hysteresis delay on reconnection. The switchover latency is 3 µs, and the device supports VBAT voltages exceeding VDD-critical for lithium backup cells. This behavior is confirmed in the functional block diagram and timing diagrams of the TPS3617-50DGK datasheet.

Can the TPS3617-50DGK monitor voltages other than VDD?

Yes-the TPS3617-50DGK includes a dedicated power-fail comparator with PFI and PFO pins. PFI accepts external voltages and compares them to an internal 1.15-V reference; if PFI drops below 1.15 V, PFO asserts low. By adding a resistor divider, users can supervise any voltage ≥1.15 V (e.g., 3.3-V or 2.5-V rails). The PFI input draws only ±25 nA, enabling high-impedance sensing. This dual-monitoring capability is explicitly documented in the TPS3617-50DGK electrical characteristics table and functional description.

What is the watchdog timeout period for the TPS3617-50DGK, and how is it reset?

The TPS3617-50DGK watchdog timer has a nominal timeout of 0.8 s, with a guaranteed range of 0.48 s to 1.12 s over temperature. It resets on any edge-rising or falling-at the WDI pin. If unused, WDI must be left floating (not tied high/low), as external biasing increases current draw. The internal oscillator drives the timeout, and the WDI pin's transition rate must exceed 100 ns/V to ensure reliable detection. These parameters are specified in the TPS3617-50DGK timing characteristics table and watchdog section.

What package type and dimensions does the TPS3617-50DGK use?

The TPS3617-50DGK uses an 8-pin VSSOP (DGK) package per JEDEC MO-187, measuring 3.05 mm × 4.98 mm with 0.65-mm lead pitch and 1.1-mm maximum height. It features a thermally enhanced exposed pad for improved heat dissipation. The pin 1 index is located at the top-left corner, and the package marking "ASD" appears on the top surface. This mechanical data is verified in the TI Package Outline DGK0008A and Package Option Addendum for TPS3617-50DGK.