The latest wave of digital-to-analog (D/A) converters boasts solid performance, low noise, minimal distortion, super low power and minuscule footprints.
Analog Devices, Cirrus Logic, Maxim Integrated Products and AKM Semiconductor are touting strong ac performance, while National Semiconductor and Linear Technology are focusing on dc performance.
In low-, medium- and fast-speed D/A converters with less than 1-Msample/second performance, dc parameters are important specifications when comparing devices.
In high-speed D/A converters with greater than 1 Msample/s, ac or dynamic specifications are the important parameters that differentiate one device from another. The level of resolution, speed, static and dynamic performance required by the D/A converter varies according to differing applications such as communications, instrumentation and automatic test equipment.
Cirrus Logic Inc.'s (Austin, Texas) six-channel, 24-bit, 192-kHz single-chip D/A converter claims to deliver high audio quality for entry-level multichannel audio systems and surround-sound applications. Cirrus said the CS4361's multibit delta-sigma architecture is the reason for the device’s high audio quality, which includes 105-dB dynamic range, negligible distortion and jitter sensitivity packed in a 20-pin TSSOP (6.5 x 6.4 mm).
Maxim Integrated Products Inc. (Sunnyvale, Calif.) has introduced a variety of low-power 12-, 14- and 16-bit dual D/A converters. The MAX5873-MAX5878, MAX5893-MAX5895 and MAX5898 are said to deliver exceptional dynamic performance up to Nyquist, tight gain and offset matching.
Maxim's D/A converters are optimized for baseband transmit architectures with analog quadrature mixing, phased arrays and diversity transmit applications. At
200 Msamples/s, the 12-bit MAX5873 delivers 78-dBc spurious-free dynamic range (SFDR) at 16 MHz output frequency, while consuming only 255 milliwatts. With a
two-tone intermodulation (IMD) at 10-MHz output frequency. Available in a 68-pin QFN-EP (10 x 10 mm), the devices consume only 1.1 W.
Analog Devices Inc. (Norwood, Mass.) has developed a lower-power version of its TxDAC transmit D/A converters that it says reduces power dissipation by up to 70 percent over its previous generation. The AD970x family supports update rates of 175 Msamples/s an operating rate that is said to be four times that of its nearest competitor. The 8-, 10- and 12-bit D/A converter family features SFDR of 86 dBc and IMD of 70 dBc to 50 MHz.
Despite the AD970x's small size (32-lead FLCSP, 5 x 5 mm) and low power consumption (190 mW to 135 mW), all four D/A converters maintain high dynamic performance levels. “SFDR stays the same, but power consumption is dramatically lowered,” said Chuck Millet, business manager of ADI's high-speed D/A converters.
AKM Semiconductor Inc.'s (San Jose, Calif.) low-power, 24-bit 192-kHz stereo D/A converter with an integrated 3-D audio enhancement circuit is intended for ultracompact mobile phones, smart phones and portable media players. Housed in a 41-pin BGA (4 x 4 mm), the AK4368's power-management function switches the power to each circuit block on or off independently, and the microcontroller interface
is both three-wire- and I2C-bus compatible. Operating voltage ranges from 1.6 volts to 3.6 V, with power consumption of just 4 milliamps at 2.4 V. The headphone amplifier delivers up to 40 mW of output power to a 16-W speaker. The D/A converter provides dynamic range of 92 dB at the headphone amp output with a –60-dB input signal.
National Semiconductor Corp. (Santa Clara, Calif.) expanded its data conversion offering with three low-power, pin- and function-compatible 8-, 10- and 12-bit
D/A converters, with strong dc specs. The single-channel D/A converters, available in either a TSOT-6 (1.65 x 2.97-mm) or MSOP-8 (2.9 x 2.9-mm) package,
are designed to optimize performance and minimize power. For example, the 12-bit D/A converter provides typical performance of +0.25, –0.15 least significant bit
(LSB) differential nonlinearity, ±2.6 LSB integral nonlinearity (INL) and power consumption of .64 mW at 3.6 V.
The reference for each converter is derived from the power supply, resulting in the widest possible dynamic output range, said Andrew Jue, product-marketing
director for National's Data Conversion Division. A power-down feature reduces power consumption to less than 0.2 microwatt.
Linear Technology Corp.'s (Milpitas, Calif.) octal voltage output D/A converters with an I2C serial interface in a 16-pin narrow SSOP (5 x 6.2 mm) consumes the
same board area as an SO-8. The LTC2605 (16-bit), LTC2615 (14-bit) and LTC2625 (12-bit) D/A converters establish new board-density benchmarks for 16- and
14-bit D/A converters, according to Linear Technology.
At 16 bits, the LTC2605 achieves one of the industry's smallest footprints for octal D/A converters, while improving dc performance over competitive products, the company said.