Texas Instruments UCD3138RGCR

Overview

UCD3138RGCR from Texas Instruments is a highly integrated digital power controller for isolated DC-DC and AC-DC applications, featuring three independent PID-based hardware control loops, 8 high-resolution DPWM outputs with 250-ps pulse width resolution, and a 31.25 MHz ARM7TDMI-S processor with 32 KB flash and 4 KB RAM. It supports voltage, peak/average current, constant current, and constant power modes up to 2 MHz switching frequency.

For engineers reviewing the UCD3138RGCR datasheet, UCD3138RGCR pinout, UCD3138RGCR application, or UCD3138RGCR equivalent, key selection considerations include DPWM timing resolution (4 ns), EADC resolution (as low as 1 mV/LSB), dual UART support, 64-pin VQFN package thermal performance, and hardware-accelerated burst mode and ideal diode emulation for light-load efficiency.

Technical Context

The UCD3138RGCR implements three dedicated Digital Power Peripherals (DPPs), each integrating an Error ADC (EADC), configurable 2-pole/2-zero digital compensator, and paired DPWM outputs - enabling simultaneous regulation of multiple isolated outputs without CPU intervention. Its front-end architecture supports primary-side voltage sensing, copper trace current sensing, and flux balancing for non-peak current mode topologies.

Hardware acceleration extends to fault handling: seven high-speed analog comparators enable cycle-by-cycle current limiting with programmable blanking time, while 10 digital comparators monitor ADC outputs for overvoltage, undervoltage, and thermal events. Synchronization logic allows phase-aligned DPWM waveforms across multiple UCD3138 family devices in master-slave configurations.

Key Specifications

Pinout & Package

UCD3138RGCR is housed in a thermally enhanced 64-pin VQFN (RGC) package measuring 9.00 mm × 9.00 mm with exposed thermal pad. The package supports high-power density layouts and requires controlled-impedance routing for DPWM and EADC signal integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digital power controller applications.

Compared with UCD3138A64PFC and UCC2897A, the UCD3138RGCR uniquely balances hardware-accelerated digital control (3 DPPs, 8 DPWMs) with embedded ARM firmware extensibility in a compact 64-pin VQFN - making it optimal for space-constrained, multi-topology isolated supplies requiring field-upgradable features and PMBus compliance.

Availability

UCD3138RGCR is available at Aetrix Electronics and suitable for telecom rectifiers, server PSUs, and industrial UPS systems requiring stable component supply, long-term lifecycle assurance, and TI-qualified production lots.

Supply support for UCD3138RGCR 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 expertise in digital power control ICs and reference design ecosystems.

The UCD3138 product line was engineered specifically for high-efficiency, isolated power conversion - targeting AC-DC rectifiers, telecom infrastructure, and server PSUs where integration, thermal performance, and digital configurability reduce bill-of-materials and accelerate time-to-market.

FAQ

What is the maximum DPWM switching frequency supported by the UCD3138RGCR?

The UCD3138RGCR supports DPWM operation up to 2 MHz. This high-frequency capability enables compact magnetics design and improved transient response in GaN-based isolated DC-DC converters. The 4-ns frequency resolution ensures precise timing control across the full range, and the hardware-implemented DPWM module operates independently of the ARM7TDMI-S core to guarantee deterministic timing behavior.

Does the UCD3138RGCR support peak current mode control, and how is it implemented?

Yes, the UCD3138RGCR supports peak current mode control using its dedicated front-end 2 circuitry (EAP2/EAN2 inputs). This path includes a high-speed comparator with programmable blanking time and direct cycle-by-cycle current limiting - bypassing the main EADC path for sub-microsecond response. Peak current mode is configured via firmware registers and works alongside voltage and average current modes, allowing topology-specific optimization without hardware changes.

How many UART interfaces does the UCD3138RGCR provide, and what are their pin assignments?

The UCD3138RGCR provides two UART interfaces: UART0 (SCI_RX0 on Pin 12, SCI_TX0 on Pin 13) and UART1 (SCI_RX1 on Pin 30, SCI_TX1 on Pin 29). Both support standard asynchronous serial communication at configurable baud rates and are accessible without multiplexing conflicts in the 64-pin RGC package. UART0 is commonly used for debug and firmware updates, while UART1 supports host MCU telemetry or secondary peripheral interfacing.

Can the UCD3138RGCR synchronize DPWM outputs with other UCD3138-family devices?

Yes, the UCD3138RGCR supports hardware synchronization of DPWM waveforms across multiple UCD3138-family devices using dedicated SYNC_IN and SYNC_OUT pins (e.g., Pin 11 and Pin 37). This enables precise phase alignment in paralleled or interleaved power stages - critical for current sharing in multi-module telecom rectifiers. Synchronization is fully hardware-managed and does not rely on ARM firmware coordination, ensuring jitter-free operation even under heavy CPU load.

What is the role of the internal temperature sensor in the UCD3138RGCR, and how is it accessed?

The UCD3138RGCR includes an on-die temperature sensor monitored via ADC channel AD13 (Pin 2), providing real-time junction temperature data for thermal derating and fan control. The sensor is factory-calibrated and delivers 12-bit readings with ±2°C accuracy over –40°C to 125°C. It is accessed through the ADC sequencer and can trigger hardware interrupts or PMBus alerts when thresholds are exceeded - enabling proactive thermal management without host MCU intervention.