Texas Instruments TMS320F28021DAS

Overview

TMS320F28021DAS from Texas Instruments is a 32-bit C28x-core microcontroller optimized for real-time motor control and digital power applications, operating at 40 MHz (25-ns cycle time), featuring 8 kB flash, 3 kB SARAM, 3-channel 12-bit ADC with 500-ns conversion time, and 8 ePWM channels with HRPWM support in a 38-pin TSSOP package rated for –40°C to 125°C.

For engineers reviewing the TMS320F28021DAS datasheet, TMS320F28021DAS pinout, TMS320F28021DAS application, or TMS320F28021DAS equivalent, key selection considerations include its 40-MHz deterministic C28x CPU, integrated analog comparators with direct PWM routing, single 3.3-V supply operation, and compact DA-package footprint for space-constrained inverter designs.

Technical Context

The TMS320F28021DAS implements a Harvard-architecture C28x CPU with atomic instructions and fast interrupt response, enabling tight-loop control in motor drives. Its peripheral set includes three 32-bit CPU timers, eight ePWM modules (four with high-resolution capability), one eCAP input, and dual 12-bit ADC groups supporting simultaneous sampling.

Clocking is managed via dual zero-pin oscillators or external crystal/XCLKIN, with integrated POR/BOR and watchdog timer. The device uses an internal voltage regulator for single-rail 3.3-V operation and supports code security via 128-bit key lock on flash, SARAM, and OTP memory blocks.

Key Specifications

Pinout & Package

Package: 38-pin Thin Shrink Small-Outline Package (TSSOP), 0.65-mm pitch, 12.5 mm × 6.2 mm body size, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar real-time control applications.

Compared with TMS320F28021DAS, the TMS320F28022DA offers higher clock speed and memory for enhanced control fidelity, while the TMS320F28023DA adds SCI for system-level integration-both maintain pin-for-pin compatibility in the 38-pin DA package but require validation of flash layout and peripheral initialization.

Availability

TMS320F28021DAS is available at Aetrix Electronics and suitable for air conditioner outdoor units, micro inverters, and AC-input BLDC motor drives requiring stable component supply, long-term industrial temperature support, and TI-qualified automotive-grade reliability.

Supply support for TMS320F28021DAS 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 delivering analog and embedded processing solutions, with leadership in signal chain and real-time control technologies.

The TMS320F2802x family belongs to TI's C2000™ real-time microcontroller portfolio, designed specifically for high-precision closed-loop control in motor drives, digital power, and renewable energy systems.

FAQ

What is the maximum operating frequency of the TMS320F28021DAS?

The TMS320F28021DAS operates at a maximum CPU frequency of 40 MHz, corresponding to a 25-ns instruction cycle time. This speed is fixed for the -21 variant and is confirmed in TI's SPRS523P datasheet Table 6-1. The device does not support dynamic frequency scaling; clock configuration is set at boot via PLL and oscillator settings. All timing-critical peripherals-including ePWM, ADC, and CPU timers-are synchronized to this 40-MHz base clock.

Does the TMS320F28021DAS include a UART interface?

No, the TMS320F28021DAS does not include a Serial Communications Interface (SCI) UART peripheral. According to TI's device comparison table (SPRS523P, Table 6-1), SCI is absent in the F28021 variant. It provides SPI and I²C interfaces only. If UART functionality is required, engineers should consider the pin-compatible TMS320F28023DA, which integrates one SCI module while retaining the same 38-pin DA package and temperature rating.

What analog peripherals are integrated into the TMS320F28021DAS?

The TMS320F28021DAS integrates a 12-bit dual-sample-and-hold ADC with 7 input channels (Group A only), two analog comparators (COMP1 and COMP2) with internal 10-bit references, an on-chip temperature sensor, and dedicated analog I/O pins (AIO2, AIO4, AIO6, AIO10, AIO12, AIO14). It lacks Group B ADC channels and second comparator inputs found in higher variants like the F28023, per Table 6-1 and Section 7.2.1 signal descriptions.

Is the TMS320F28021DAS pin-compatible with other F2802x DA-package devices?

Yes, the TMS320F28021DAS is fully pin-compatible with all other 38-pin DA-package F2802x variants-including TMS320F28020DA, TMS320F28022DA, and TMS320F28023DA-as confirmed by identical pin diagrams in Figure 7-2 of SPRS523P. Signal mapping, power pin locations, and JTAG interface are identical; differences lie only in internal memory size, clock speed, and peripheral enablement-not pin function or placement.

What is the purpose of the VREGENZ pin on the TMS320F28021DAS?

The VREGENZ pin on the TMS320F28021DAS controls the internal voltage regulator enable/disable function. When pulled high, it activates the on-chip 1.8-V regulator for core logic; when pulled low, the regulator is disabled and an external 1.8-V supply must be provided. This pin allows flexible power architecture design and is required to be externally biased-TI specifies a pull-up resistor for normal operation. Its state is sampled at power-up and determines boot behavior.