Texas Instruments TPS3617-50DGKR

Overview

TPS3617-50DGKR from Texas Instruments is a battery-backup supervisor IC for RAM retention in 5-V systems, featuring precision 4.55-V supply monitoring, 800-ms watchdog timeout, 100-nA battery supply current, active-low push-pull RESET, and VDD-to-VBAT switchover with <1-Ω on-resistance. It enables data integrity during power loss in portable battery-powered equipment.

For engineers reviewing the TPS3617-50DGKR datasheet, TPS3617-50DGKR pinout, TPS3617-50DGKR application, or TPS3617-50DGKR equivalent, key selection criteria include reset threshold accuracy (±1.5% over temperature), ultra-low battery leakage, integrated watchdog timer timing tolerance (±40%), and MSOP-8 package compatibility with space-constrained embedded designs.

Technical Context

This device implements dual-path power management: a precision bandgap-based voltage monitor triggers RESET when VDD falls below 4.55 V (typ), while an independent comparator monitors PFI against a 1.15-V internal reference to assert PFO. The switchover logic uses PMOS and NMOS switches to route VOUT between VDD and VBAT based on real-time voltage comparison and hysteresis (VBSW = 55 mV at VDD = 1.8 V).

The watchdog circuit employs an internal oscillator with 0.8-s nominal timeout; WDI accepts either edge-triggered transitions and includes internal pull-down biasing. Battery freshness seal functionality-exclusive to TPS3617 variants-is activated via specific PFI/PFO/VDD sequencing and disables internal battery loading until first power-up.

Key Specifications

Pinout & Package

TPS3617-50DGKR is housed in an 8-pin VSSOP (DGK) package measuring 3.05 mm × 4.98 mm with 0.65-mm lead pitch and maximum height of 1.1 mm. The exposed pad is not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3617-50DGKR, TPS3618-50DGKR offers higher temperature capability but forfeits battery preservation; MAX6361LUT+T reduces footprint and cost but sacrifices programmability, PFI monitoring, and ultra-low 100-nA battery drain essential for decade-long backup.

Availability

TPS3617-50DGKR is available at Aetrix Electronics and suitable for portable battery-powered equipment, point-of-sale terminals, and advanced modems requiring stable component supply with long-lifecycle support and guaranteed traceability.

Supply support for TPS3617-50DGKR 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and digital signal processing technologies with over 50 years of innovation in power management and interface solutions.

The TPS3617 product line was designed specifically for battery-backed RAM retention in space-constrained, low-power embedded systems where data integrity during power interruption is mission-critical.

FAQ

What is the reset threshold voltage of the TPS3617-50DGKR and how stable is it over temperature?

The TPS3617-50DGKR has a nominal reset threshold (VIT) of 4.55 V with ±1.5% variation across the full operating temperature range of –40°C to +85°C. This stability is achieved through precision bandgap referencing and on-die trimming, ensuring consistent brownout detection without external calibration. The TPS3617-50DGKR datasheet specifies VIT hysteresis of 60 mV at 5-V operation, further enhancing noise immunity during supply recovery.

How does the battery freshness seal function in the TPS3617-50DGKR?

The battery freshness seal in the TPS3617-50DGKR isolates the VBAT pin from internal circuitry until the first power-up sequence. Activation requires grounding PFO, connecting PFI to VDD, then applying VDD > VIT for 5–35 ms. Once enabled, the seal disables permanently upon the rising edge of RESET. This ensures the backup battery remains fully charged until final product deployment. The TPS3617-50DGKR is the only variant in the family with this feature.

Can the TPS3617-50DGKR monitor voltages other than the main 5-V supply?

Yes, the TPS3617-50DGKR includes a dedicated power-fail comparator with PFI and PFO pins. PFI compares an external voltage against a 1.15-V internal reference; if the input falls below this threshold, PFO asserts low. By adding two 1-MΩ resistors in a voltage divider, users can supervise any supply above 1.15 V. The TPS3617-50DGKR datasheet specifies 12-mV hysteresis on PFI to prevent chatter near the trip point.

What is the maximum continuous output current supported by the TPS3617-50DGKR's VOUT pin?

The TPS3617-50DGKR supports up to 300 mA continuous output current at VOUT in both VDD and VBAT modes. In VDD mode, RDS(on) is 0.6 Ω (max), limiting voltage drop to 180 mV at 300 mA; in VBAT mode, RDS(on) is 15 Ω (max), suitable for typical CMOS RAM standby loads (<100 µA). Exceeding 300 mA risks thermal shutdown or parametric shift. The TPS3617-50DGKR absolute maximum rating for VOUT current is 400 mA, but sustained operation above 300 mA is not recommended per datasheet derating guidelines.

Is the watchdog timer in the TPS3617-50DGKR configurable, and what happens if WDI is left unconnected?

The watchdog timer in the TPS3617-50DGKR has a fixed 0.8-s nominal timeout and is not user-configurable. If WDI is left floating, the internal 40-kΩ pull-down activates, holding WDI low and disabling the watchdog function - no RESET assertion occurs due to timeout. To enable watchdog monitoring, the host processor must toggle WDI (either edge) at least once every 0.8 s. The TPS3617-50DGKR watchdog section recommends pulsing WDI low-high-low within 7/8 of the timeout period to minimize current draw.