Texas Instruments UCC29002D/1

Overview

UCC29002D/1 from Texas Instruments is an advanced 8-pin BiCMOS load-share controller for N+1 redundant power systems, delivering <1% current-share error at full load, ultra-low offset (±100 µV) current-sense amplification, and Intel® SSI-compliant single-wire load-share bus operation in server and telecom DC-DC module paralleling applications.

For engineers reviewing the UCC29002D/1 datasheet, UCC29002D/1 pinout, UCC29002D/1 application, or UCC29002D/1 equivalent, key selection criteria include high-side/low-side current-sense flexibility, LS bus fault protection thresholds (VLS < 2/3×VCSO or VLS > VVDD − 0.7 V), start-up behavior (adjust current follows VEAO, not forced max), and VSSOP-8 package compatibility with remote-sense OEM power supplies.

Technical Context

The UCC29002D/1 implements automatic leader/follower architecture using a post-package-trimmed current-sense amplifier (gain ≥3, GBW = 2 MHz, CMRR ≥75 dB) and transconductance error amplifier (gM = 14 mS) to balance output currents across parallel modules. Its differential CS+/CS− inputs support GND-referenced or high-side shunt placement with 0 V to VDD common-mode range.

It features dual-stage LS bus control: a unity-gain driver with ideal-diode behavior establishes leadership dynamically, while a 15 kHz-filtered receiver monitors bus voltage (VLS) and triggers fault shutdown if VLS falls outside [2/3×VCSO, VVDD − 0.7 V]. Start-up logic differs from UCC29002/UCC39002 by omitting forced 3 V adjust input-ADJ current scales linearly with VEAO from power-on.

Key Specifications

Pinout & Package

UCC29002D/1 is housed in an 8-pin VSSOP package (3.00 mm × 4.90 mm), optimized for space-constrained board layouts in multi-rail power systems.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar load-share controller applications.

Compared with UCC29002D/1, UCC29002DR trades thermal performance for mechanical compatibility, while UCC39002DGKR sacrifices extended temperature operation for cost reduction-neither offers pin-to-pin replacement without verifying thermal and environmental margins.

Availability

UCC29002D/1 is available at Aetrix Electronics and suitable for telecom rectifier modules, server PSU redundancy, industrial PLC backplanes, and medical imaging power racks requiring stable component supply across long production lifecycles.

Supply support for UCC29002D/1 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 ICs, with decades of expertise in high-reliability power system solutions.

The UCC29002 family was designed specifically for N+1 redundant DC-DC module paralleling in server, telecom, and industrial infrastructure-emphasizing accuracy, fault resilience, and ease of integration with off-the-shelf power supplies.

FAQ

What distinguishes UCC29002D/1 from UCC29002 and UCC39002 in start-up behavior?

The UCC29002D/1 implements the UCC29002-1 variant's start-up logic: ADJ current scales directly with VEAO from power-on, avoiding the forced 3 V adjust input used in UCC29002/UCC39002. This yields slower, smoother load engagement-critical in systems sensitive to rapid dV/dt on shared output buses. All other electrical characteristics and pin functions of UCC29002D/1 match the UCC29002 baseline.

Can UCC29002D/1 support high-side current sensing in a 48 V output system?

Yes-UCC29002D/1's current-sense amplifier accepts common-mode voltages from 0 V to VDD, allowing direct connection of the shunt in the +48 V rail if VDD ≥ 48 V. However, since VDD max is 13.5 V, TI recommends placing the shunt in the GND return path and using the UCC29002D/1's 0 V–13.5 V CS+/CS− range with appropriate scaling. This avoids level-shifting complexity and preserves ±100 µV offset accuracy.

How does UCC29002D/1 protect against load-share bus faults?

UCC29002D/1 continuously monitors VLS with a window comparator: it asserts fault if VLS < 2/3×VCSO (short to GND) or VLS > VVDD − 0.7 V (short to supply). Upon fault detection, the LS bus driver disconnects, ADJ current sinks to zero, and the device enters disabled mode-preventing incorrect voltage adjustment and maintaining system stability. This protection operates independently of external circuitry.

What is the maximum number of modules that can be paralleled using UCC29002D/1?

The practical limit is governed by the LS bus driver's output current (IOUT_LS ≥ −1.5 mA min) and follower input impedance (100 kΩ). Using Equation 1 from the datasheet-Nm = IOUT,MIN / (VLS,FULL_SCALE / 100 kΩ)-and assuming VLS,FULL_SCALE = 10 V, up to ~15 modules can be supported. However, accuracy degrades below 3× gain, so TI recommends ≤10 modules for <1% current-share error. Layout parasitics further constrain real-world scalability.

Does UCC29002D/1 require external compensation components?

Yes-UCC29002D/1 requires external RC networks on EAO and ADJ pins for loop stability. The EAO pin connects to a transconductance amplifier; compensation (typically a series RC from EAO to GND) sets dominant pole frequency (~15 kHz per internal filter). The ADJ pin interfaces with the DC-DC controller's feedback divider; RADJ and RSENSE values set gain and bandwidth. TI provides design equations and layout guidelines in SLUS495J Section 7.4.