Microchip Technology AT73C209

Overview

AT73C209 from Microchip Technology (formerly Atmel) is a fully integrated stereo audio DAC and power management IC for battery-powered portable audio devices. It delivers 93 dB SNR playback, supports 8–48 kHz sampling rates, integrates 32 Ω/20 mW headset drivers with volume/mute control, and includes a 100 mA DC/DC boost converter and dual LDOs for USB/battery supply management - used in MP3 players, digital cameras, and handheld GPS units.

For engineers reviewing the AT73C209 datasheet, AT73C209 pinout, AT73C209 application, or AT73C209 equivalent, key selection considerations include its programmable 16/18/20-bit DAC resolution, SPI-configurable LDO outputs (2.7–3.5 V @ 150 mA and 2.4–3.0 V @ 60 mA), I²S audio interface timing, and integrated microphone preamplifier with bias generation.

Technical Context

The AT73C209 implements a multibit sigma-delta DAC architecture with dithering and cascaded half-band + SINC interpolation filters, achieving high jitter immunity and eliminating baseband image artifacts. Its digital audio path supports I²S, MSB-justified, and LSB-justified formats with programmable word length (16/18/20 bits) and de-emphasis filtering.

Power management integrates a DC/DC boost converter (0.9–1.8 V input → 2.6–3.3 V @ 100 mA) with external inductor/diode, plus two digitally programmable LDOs: LDO1 (2.7–3.5 V / 150 mA, USB-supplied) and LDO2 (2.4–3.0 V / 60 mA, low-noise analog supply), both controlled via SPI registers.

Key Specifications

Pinout & Package

AT73C209 is housed in a 33-pin QFN package (5 mm × 5 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per Table 5-1 of datasheet 6365A–PMAAC–12-Mar-08, including dedicated analog/digital supply, ground, audio I/O, SPI, and power management terminals.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar stereo audio DAC and power management applications.

Compared with AK4384VN and TPA6138A2RTJR, the AT73C209 uniquely combines DAC, headset drivers, microphone preamp, DC/DC boost, and dual LDOs in one die - reducing component count and simplifying layout for cost-sensitive, battery-operated consumer audio devices.

Availability

AT73C209 is available at Aetrix Electronics and suitable for portable music players, digital cameras, and handheld GPS navigation units requiring stable component supply and long-term production continuity.

Supply support for AT73C209 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

Microchip Technology Inc. is a leading provider of microcontrollers, analog components, and connectivity solutions, acquired Atmel in 2016 and maintains full product support for legacy Atmel PMAAC portfolio.

The AT73C209 belongs to Microchip's Power Management and Analog Companions (PMAAC) product line, designed specifically to integrate audio conversion and multi-rail power regulation for ultra-low-power portable consumer electronics.

FAQ

What is the maximum supported sampling rate for the AT73C209 DAC?

The AT73C209 supports sampling rates up to 48 kHz, including standard audio frequencies such as 8, 11.024, 16, 22.05, 24, 32, 44.1, and 48 kHz. This is confirmed in the device description and DAC_CSFC register documentation, where master clock options (256× or 384× Fs) are explicitly tied to these input rates. The AT73C209 does not support 96 kHz or higher sampling rates.

Does the AT73C209 include hardware-based short-circuit protection for headset outputs?

Yes, the AT73C209 includes dedicated hardware short-circuit detection for both left and right headset channels. Pins HSL and HSR report short conditions via persistent status flags (MISC_STATUS[0:1]), which remain set until cleared by reset or explicit register write. This enables reliable fault monitoring without continuous software polling.

Can the AT73C209 operate from a single 0.9 V alkaline cell?

Yes, the AT73C209 is explicitly rated for battery input from 0.9 V to 1.8 V - supporting operation down to a nearly depleted alkaline AA/AAA cell. Its integrated DC/DC boost converter (SW1) generates a stable 3.3 V output under this condition, as verified in Section 9.1.1 and Absolute Maximum Ratings (Table 6-1).

How is the AT73C209's microphone bias voltage generated and controlled?

The AT73C209 generates microphone bias (MICB, Pin 6) internally and controls it via the MIC_CTRL register (0x17). Bit ONMIC (bit 0) enables the bias circuit, and the bias level is fixed per design - no external adjustment or programmable voltage selection is provided. MICB is intended for electret condenser microphones requiring ~2.0 V bias.

What audio interface protocols does the AT73C209 support besides standard I²S?

In addition to standard I²S, the AT73C209 supports MSB-justified and LSB-justified audio data formats. This is configured via the DINTSEL[5:4] bits in the DAC_MISC register (0x0A), allowing interoperability with diverse host processors and DSPs that use non-I²S-aligned serial audio interfaces.