Texas Instruments UCC1913J

Overview

UCC1913J from Texas Instruments is a negative-voltage hot-swap circuit breaker IC referenced to VSS, providing programmable overcurrent protection, average power limiting, and fault retry timing for -48V telecom and industrial power systems. It features 50mV precision fault threshold, 9.5V internal shunt regulator, 3% maximum fault duty cycle, and operates across –55°C to +125°C.

For engineers reviewing the UCC1913J datasheet, UCC1913J pinout, UCC1913J application, or UCC1913J equivalent, this page delivers verified technical context, real-world design meaning of key specs, SOIC-8 package mapping, and two validated alternative parts for negative-rail power management in high-reliability DC distribution.

Technical Context

The UCC1913J integrates a current-driven control architecture where VDD is externally resistor-fed to ground, enabling operation referenced to the most negative rail (VSS). Its fault detection uses a fixed 50mV sense threshold across SENSE–VSS, while IMAX pin voltage sets maximum sourcing current as V_IMAX/R_SENSE.

Fault timing relies on CT pin charging with 36µA base current plus programmable PL-pin current proportional to FET drain-source voltage above 5V - enabling dynamic average power limiting. The internal UVLO disables operation below 6V (min), and SD/FLT provides open-drain fault indication and shutdown control.

Key Specifications

Pinout & Package

UCC1913J is housed in an 8-pin SOIC package (N or J suffix), with exposed pad not present. Pin functions are validated per TI SLUS274 (1999) and confirmed via official connection diagrams and pin descriptions.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar negative-rail circuit breaker applications.

Compared with UCC1913J, UCC2913J offers identical functionality at reduced temperature grade and cost, while TPS23753APWR serves a fundamentally different architecture (positive-rail PoE PD) and cannot replace UCC1913J in negative-voltage hot-swap roles.

Availability

UCC1913J is available at Aetrix Electronics and suitable for telecom -48V distribution, industrial negative-rail PSUs, and server backplane protection requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for UCC1913J 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, delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The UCC1913J belongs to TI's legacy linear power management family, designed specifically for high-reliability negative-voltage hot-swap and circuit protection in telecom infrastructure and ruggedized industrial systems.

FAQ

What is the operating temperature range of the UCC1913J?

The UCC1913J is specified for junction temperatures from –55°C to +125°C. This extended range enables deployment in uncontrolled environments such as outdoor telecom cabinets or industrial motor control enclosures where ambient extremes are common. The UCC1913J maintains full electrical performance across this range, including stable 50mV fault threshold and accurate CT timing - critical for reliable fault response in mission-critical systems.

How does the UCC1913J implement average power limiting?

The UCC1913J implements average power limiting through its PL (Power Limit) pin, which sinks current proportional to (V_DS – 5V)/R_PL when the NMOS pass FET's drain-source voltage exceeds 5V. This current adds to the CT capacitor charging current, reducing output duty cycle from 3% toward 0.1%. As a result, the UCC1913J automatically caps average FET power dissipation regardless of load current - a feature confirmed in TI SLUS274 Figure 4 and application equations.

Can the UCC1913J be used with positive supply rails?

No - the UCC1913J is explicitly designed for negative-voltage applications and is referenced to VSS, the most negative potential in the system. Its internal architecture, including the 50mV fault comparator and 9.5V shunt regulator, assumes VSS as the ground reference. Attempting to use UCC1913J with positive rails violates absolute maximum ratings and will result in improper operation or device damage. For positive-rail hot-swap, TI recommends the UCCx912 or TPS237xx families.

What is the purpose of the SD/FLT pin on the UCC1913J?

On the UCC1913J, the SD/FLT pin serves dual functions: it provides open-drain fault status output (driven high during fault or UVLO) and accepts external shutdown commands (pulling >20µA into the pin disables the output). This bidirectional capability enables system-level fault reporting to microcontrollers and coordinated power sequencing - for example, tying SD/FLT to a host processor's interrupt pin while also allowing that processor to force safe shutdown before maintenance.

How is the maximum output current programmed on the UCC1913J?

The maximum output sourcing current on the UCC1913J is programmed via the IMAX pin voltage: I_OUT(MAX) = V_IMAX/R_SENSE. V_IMAX is set using a resistor divider from VDD (regulated at 9.5V) to ground. For example, a 200mV target on IMAX with a 10mΩ sense resistor yields 20A max current. TI confirms this relationship in the "PIN DESCRIPTIONS" section of SLUS274, noting that capacitor coupling to IMAX also enables controlled current startup.