Analog Devices Inc. ADMCF326BRZ

Overview

ADMCF326BRZ from Analog Devices is a 20 MIPS fixed-point DSP motor controller integrating ADSP-2171 core, 4K×24-bit flash memory, 12-bit ADC with six analog inputs, and three-phase 16-bit center-based PWM generator - designed for real-time AC induction, PMSM, and BLDC motor control in washing machines and refrigeration compressors.

For engineers reviewing the ADMCF326BRZ datasheet, ADMCF326BRZ pinout, ADMCF326BRZ application, or ADMCF326BRZ equivalent, key selection criteria include its 50 ns instruction cycle, programmable dead time (50 ns edge resolution), flash endurance (10,000 cycles), integrated VREF (2.50 V ±50 mV), and SOIC-28 package compatibility with industrial temperature range (–40°C to +85°C).

Technical Context

The ADMCF326BRZ implements an ADSP-2171-derived fixed-point DSP architecture with independent ALU, MAC, and barrel shifter units enabling single-cycle instruction execution. Its dual DAGs support zero-overhead looping and simultaneous dual-operand fetches from 512×24-bit program RAM and 512×16-bit data RAM.

Motor control is hardware-accelerated via a dedicated three-phase PWM block with programmable dead time, narrow pulse deletion, and special crossover logic for BLDC commutation - synchronized to ADC acquisition at up to 2.44 kHz sampling rate, with resolution scaling from 8 bits (78.1 kHz PWM) to 12 bits (4.9 kHz PWM).

Key Specifications

Pinout & Package

ADMCF326BRZ is housed in a 28-lead wide-body SOIC (SO-28) package with 1.27 mm pitch, RoHS-compliant lead finish, and thermal resistance θ_JA = 80°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar motor control applications.

Compared with ADMCF326BRZ, ADMC331ARZ offers higher processing throughput but sacrifices on-chip flash security and increases system-level BOM complexity, while TMS320F28027PTT provides superior ADC speed and PWM flexibility at the cost of integrated development tooling and simplified boot security.

Availability

ADMCF326BRZ is available at Aetrix Electronics and suitable for washing machine drives, refrigerator compressor control, and industrial variable-speed pump applications requiring stable component supply across extended product lifecycles.

Supply support for ADMCF326BRZ 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

Analog Devices is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and DSP solutions for precision signal processing and motion control.

The ADMCF326BRZ belongs to the ADMCxxx family of motor controllers, engineered specifically for cost-sensitive, high-volume white goods and industrial drive applications where integration of flash, ADC, and PWM reduces external component count.

FAQ

What is the maximum PWM switching frequency supported by the ADMCF326BRZ?

The ADMCF326BRZ supports a minimum switching frequency of 150 Hz and achieves optimal ADC resolution (12 bits) at 4.9 kHz PWM frequency. Its 50 ns edge resolution allows practical implementation up to 78.1 kHz, though ADC resolution degrades to 8 bits at that rate. The device's 20 MIPS core ensures sufficient margin for FOC calculations even at higher frequencies, making ADMCF326BRZ suitable for both low-RPM torque control and high-speed fan applications.

Does the ADMCF326BRZ require an external crystal or can it use a clock signal?

The ADMCF326BRZ supports both configurations: a parallel-resonant fundamental-mode crystal (e.g., 10 MHz) connected between CLKIN and XTAL pins, or a TTL-compatible external clock applied solely to CLKIN. In crystal mode, internal oscillator circuitry generates CLKOUT at twice the crystal frequency; in external clock mode, XTAL must remain unconnected. ADMCF326BRZ's clock architecture ensures deterministic 50 ns instruction timing regardless of source, critical for synchronous motor control loops.

How does the boot-from-flash feature work on the ADMCF326BRZ?

The ADMCF326BRZ boot-from-flash feature is enabled by setting a one-time programmable code via the ROM-based flash utility. When set, the processor jumps directly to address 0x2200 in flash memory after reset, bypassing the internal ROM monitor. This prevents external debug access and protects firmware IP. To reprogram, the running application must call flash_init (erases all flash) or auto_erase_reg (preserves code) - triggered by a GPIO condition like PIO6 high at startup. ADMCF326BRZ thus balances security with field-upgrade capability.

Can the ADMCF326BRZ ADC measure signals beyond the 0.3 V to 3.5 V range?

No - the ADMCF326BRZ ADC inputs (V1–V3, VAUX0–VAUX2) are strictly rated for 0.3 V to 3.5 V absolute input voltage per datasheet specifications. Exceeding this range risks damage or inaccurate conversion due to internal ESD clamp activation. For wider-range sensing (e.g., ±10 V motor phase voltages), external signal conditioning - such as resistive dividers and rail-to-rail op-amps referenced to VREF - is required before connecting to ADMCF326BRZ analog inputs. The device's internal 2.50 V reference ensures consistent scaling across all six channels.

Is the ADMCF326BRZ pin-compatible with other ADMCxxx family members?

No - the ADMCF326BRZ uses a unique 28-pin SOIC footprint optimized for motor control peripherals, and is not pin-compatible with ADMC300, ADMC331, or ADMC401 devices. While code-compatible with the ADSP-21xx DSP family, pin assignments differ significantly: ADMCF326BRZ dedicates six pins exclusively to PWM outputs (AH/AL/BH/BL/CH/CL) and integrates ADC inputs directly, whereas other ADMC parts allocate pins differently for CAN, additional timers, or external memory interfaces. Board redesign is required when substituting ADMCF326BRZ into legacy ADMC layouts.