Directories Product Focus

ADCs and DACs

Written by Jeff Child

Resolution and Speed

ADCs and DACs are two of the key IC components that enable digital systems to interact with the real world. Makers of analog ICs are constantly evolving their DAC and ADC chips pushing the barriers of resolution and speed.

As critical enablers serving a wide variety of embedded applications, analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) are available in many combinations of high-speed or high-resolution—or some tradeoff of both. Analog IC vendors continue to innovate, enhancing the performance and architectures of these critical devices.

For high-speed DACs the subsets of products include wideband radio frequency, intermediate frequency signal processing and general-purpose baseband classes. System designers use these DACs in wired and wireless communications, instrumentation, radar, electronic warfare and general waveform synthesis. The latest and greatest high-speed ADCs meanwhile seek to blend the high performance and optimized power consumption necessary for today’s demanding receiver/data acquisition applications. These products are used in wired and wireless communications, instrumentation, radar, electronic warfare and general data acquisition.
Simultaneous sampling capability is offered in some ADCs. That enables a single ADC device to take two or more measurements at the exact same time. This is particularly useful for systems where signal levels change quickly, such as motor control, distribution automation and ultrasound. Such systems benefit from the added precision that simultaneous sampling provides.

Resolution overrides demands for high speed for devices like precision DACs. These operate at less than 30 MHz and are critical data conversion components used in most high-performance signal processing systems. High-precision DACs range from 8 bits to 20 bits in resolution.
More than 100,000 ADCs from Analog Devices are used within CERN’s Large Hadron Collider (LHC) (Figure 1). Located outside Geneva, Switzerland, in a tunnel 100 meters underground and 27 kilometers in circumference, the LHC is one of the most sophisticated and expensive scientific instruments ever developed. CERN depends on ADI’s AD9042 high- speed, low-power monolithic 12-bit ADCs for high reliability and performance to ensure a continuous stream of ultraprecise data during carefully orchestrated, resource intensive LHC experiments. Maintaining 80 dB spurious-free dynamic range (SFDR) over a bandwidth of 20 MHz, AD9042 ADCs support the dynamic range required to measure the energy captured by an array of 64,000 lead tungstate crystals. These scintillating crystals are designed to absorb particles formed as electrons, positrons, and photons pass through the LHC’s electromagnetic calorimeter.

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ADC Delivers 12-Bit, 10.25-GSPS RF Performance

single 12-bit, 10.25 GSPS, RF ADC with a 6.5 GHz input bandwidth. The AD9213 has been optimized to support high dynamic range frequency and time domain applications requiring wide instantaneous bandwidth and low code error rates (CER). The AD9213 features a 16-lane JESD204B interface to support its maximum bandwidth capability.
• High instantaneous dynamic range
• Noise spectral density 154 dBFS/Hz
• SFDR 68 dBc (1 GHz, −1 dBFS)
• Low power consumption: 5.1 W at 10 Gsps
• Integrated Input Buffer (6.5 GHz input bandwidth)
• 1.4 Vp-p full-scale input with RIN=50 Ω
• Overvoltage protection
• 16-lane JESD204B output (up to 16 Gbps line rate)
• Multichip sync capable with 1 sample accuracy
• DDC NCO synchronization included

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24-Bit, 6-Channel, Delta-Sigma ADC Sports I2C Interface

Maxim Integrated’s MAX11261 is a 6-channel, 24-bit delta-sigma ADC that achieves exceptional performance while consuming very low power. Sample rates up to 16 ksps allow precision DC measurements. The device also features a 64-entry, on-chip FIFO to offload the host processor. The MAX11261 communicates through an I2C-compatible serial interface and is available in a small, wafer-level package (WLP).
• Analog supply: 2.7 V to 3.6 V
• Digital supply: 1.7 V to 2.0 V, or 2.0 V to 3.6 V
• PGA Low-noise mode: 6.2 nV/√Hz noise
• Fully differential signal and reference inputs
• Internal system clock of 8.192 MHz
• I2C-compatible serial interface
• Supports standard, fast-mode, and fast-mode plus I2C
• 64-entry on-chip FIFO
• Hardware interrupt for input monitoring and FIFO usage
• WLP 2.838 mm x 2.838 mm x 0.5 mm
• -40°C to +85°C temperature range

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Precision 24-Bit Sigma Delta ADC Features Tiny Footprint

The ADS122C04 from Texas Instruments is a precision, 24-bit, ADC that offers many integrated features to reduce system cost and component count in applications measuring small sensor signals. The device features two differential or four single-ended inputs through a flexible input multiplexer (MUX), a low-noise, programmable gain amplifier (PGA), two programmable excitation current sources, a voltage reference, an oscillator and a precision temperature sensor.
• Current consumption 315 μA (typ.)
• Wide supply range: 2.3 V to 5.5 V
• Programmable gain: 1 to 128
• Programmable data rates: Up to 2 kSPS
• Up to 20 bits effective resolution
• Two differential or four single-ended inputs
• I2C-compatible interface
• 16 pin-configurable I2C addresses
• Package: 3.0-mm × 3.0-mm × 0.75-mm WQFN

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16-Bit DAC Provides Low Power Industrial Solution

Analog Devices’ AD5758 is a single channel, voltage and current output DAC that operates with a power supply range from −33 V (minimum) on AVSS to +33 V (maximum) on AVDD1 with a maximum operating voltage between the two rails of 60 V. On-chip dynamic power control (DPC) minimizes package power dissipation, which is achieved by regulating the supply voltage (VDPC+) to the VIOUT output driver circuitry from 5 V to 27 V using a buck DC-DC converter, optimized for minimum onchip power dissipation. The CHART pin enables a HART signal to be coupled onto the current output.
• 16-bit resolution and monotonicity
• DPC for thermal management
• Current/voltage output available on a single terminal
• User-programmable offset and gain
• Advanced On-chip diagnostics including a 12-bit ADC
• On-chip reference
• Output fault protection
• -40°C to +115°C temperature range
• 32-lead, 5 mm × 5 mm LFCSP package

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16-Bit DAC Delivers Direct
RF Synthesis of 1,000 MHz
Bandwidth

The MAX5855 from Maxim Integrated
is a high-performance, interpolating
and modulating, 16-bit, 4.9 Gsps RF
DAC that can directly synthesize up to
1,000 MHz of instantaneous bandwidth
from DC to frequencies greater than
2.45 GHz. The device is optimized for
cable access and digital video broadcast
applications and meets spectral
emission requirements for a broad set
of radio transmitters and modulators
including DOCSIS 3.1/3.0, DVB-C/C2,
DVB-T2, DVB-S2X, ISDB-T and EPoC.
• Eliminates I/Q imbalance and LO
feedthrough
• Enables multi-band RF modulation
• 4.9152 Gsps DAC output update rate
• High-performance 14-bit RF DAC
core
• Digital baseband I/Q with 4x
interpolation
• Sub-1 Hz NCO resolution
• Integrated clock multiplying PLL +
VCO
• 5-lane JESD204B input data interface
• Divided reference clock output
• SPI interface for device configuration

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3 Phase 5 kW AC-DC Supply is Software Configurable

Texas Instruments’ DACx0508 is a pin-compatible family of low power, eight channel, buffered voltage output DACs with 16-, 14- and 12-bit resolution. The DACx0508 includes a 2.5-V, 5-ppm/°C internal reference, eliminating the need for an external precision reference in most applications. A user selectable gain configuration provides full-scale output voltages of 1.25 V (gain = ½), 2.5 V (gain = 1) or 5 V (gain = 2).
• Linearity: ±1 LSB maximum at 16-bit resolution
• Integrated 2.5 V precision internal reference
• 20 mA drive with 0.5 V from supply rails
• User Selectable Gain: 2, 1 or 0.5
• Reset to zero scale or midscale
• Power supply: 2.7 V to 5.5 V
• Temperature range: -40˚C to 125˚C
• 50 MHz SPI compatible serial interface
• Packages: 3 mm × 3 mm, 16-pin WQFN
• Or 2.4 mm x 2.4 mm, 16-pin DSBGA

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