Single-Channel, 16-Bit Current and Voltage Output DAC with Dynamic Power ControlSeptember 26, 2019 by Paul Shepard
The AD5758 from Analog Devices is a single-channel, voltage and current output digital-to-analog converter (DAC) that operates with a power supply range from −33V (minimum) on AVSS to +33V (maximum) on AVDD1 with a maximum operating voltage between the two rails of 60V. 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 5V to 27V using a buck dc-to-dc converter, optimized for minimum on-chip power dissipation.
The CHART pin enables a HART® signal to be coupled onto the current output. The AD5758 is expected to be used in applications such as: Process control; Actuator control; Channel isolated analog outputs; Programmable logic controller (PLC) and distributed control systems (DCS) applications; and HART network connectivity.
The device uses a versatile 4-wire serial peripheral interface (SPI) that operates at clock rates of up to 50 MHz and is compatible with standard SPI, QSPI™, MICROWIRE™, DSP, and microcontroller interface standards. The interface also features an optional SPI cyclic redundancy check (CRC) and a watchdog timer (WDT). The AD5758 offers improved diagnostic features from its predecessors, such as an integrated 12-bit diagnostic analog-to-digital converter (ADC).
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Additional robustness is provided by the inclusion of a line protector on the VIOUT, +VSENSE, and −VSENSE pins. When used with its companion power management unit (PMU)/isolator (ADP1031), the AD5758 is capable of enabling designers to develop an eight channel to channel isolated analog output module with less than 2 W power dissipation, while meeting CISPR 11 Class B.
- DPC, using an integrated buck dc-to-dc converter for thermal management. When used with the ADP1031, the AD5758 enables eight channel-to-channel isolated outputs at <2W dissipated power.
- Range of advanced diagnostic features, including an integrated ADC for high reliability.
- Highly robust with output protection from miswire events (±38 V).
- HART compliant.
Features and specifications:
- 16-bit resolution and monotonicity
- DPC for thermal management
- Current/voltage output available on a single terminal
- Current output ranges: 0mA to 20mA, 4mA to 20mA,
- 0mA to 24mA, ±20mA, ±24mA, −1mA to +22mA
- Voltage output ranges (with 20% overrange): 0V to 5V, 0V to 10V, ±5V, and ±10 V
- User-programmable offset and gain
- Advanced on-chip diagnostics, including a 12-bit ADC
- On-chip reference
- Robust architecture, including output fault protection
- EMC test standards:
- IEC 61000-4-6 conducted immunity (10V, Class A)
- IEC 61000-4-3 radiated immunity (20V/m, Class A)
- IEC 61000-4-2 ESD (±6kV contact, Class B)
- IEC 61000-4-4 electrical fast transient (EFT) (±4kV, Class B)
- IEC 61000-4-5 surge (±4kV, Class B)
- 32-lead, 5mm × 5mm LFCSP
- −40°C to +115°C temperature range