DAC8562

Part: DAC8562 — Texas Instruments

Type: Dual 16-Bit Voltage-Output Digital-to-Analog Converter

Description: Low-power, dual-channel, 16-bit buffered voltage-output DAC operating from 2.7 V to 5.5 V with an integrated 2.5 V, 4-ppm/°C internal reference and 50-MHz SPI interface.

Operating Conditions:

• Supply voltage: 2.7 to 5.5 V
• Operating temperature: -40 to 125 °C
• Digital input voltage: 0 to AVDD V
• Reference input voltage: 0 to AVDD V

Absolute Maximum Ratings:

• Max supply voltage: 6 V (AVDD to GND)
• Max junction/storage temperature: 150 °C

Key Specs:

• Resolution: 16 bits
• Relative accuracy (INL): ±4 LSB typ, ±12 LSB max (using line passing through codes 512 and 65,024)
• Differential nonlinearity (DNL): ±0.2 LSB typ, ±1 LSB max (16-bit monotonic)
• Internal reference output voltage: 2.5 V (2.495 V min, 2.505 V max at TA = 25 °C)
• Reference temperature drift: 4 ppm/°C typ, 10 ppm/°C max
• Output voltage settling time: 7 μs typ (DACs unloaded), 10 μs typ (RL = 1 MΩ)
• Slew rate: 0.75 V/μs typ (measured between 20%–80% of full-scale transition)
• Glitch impulse: 0.1 nV-s typ (1-LSB change around major carry)
• Reference output drive capability: ±20 mA

Features:

• Integrated 2.5-V, 4-ppm/°C internal reference with ±5-mV initial accuracy
• Power-on reset to zero scale
• Rail-to-rail output buffer
• 50-MHz 3-wire SPI interface with Schmitt-triggered inputs
• LDAC pin for simultaneous DAC channel updates and CLR pin for asynchronous clear
• Low power consumption: 4 mW typ (at 5-V AVDD including internal reference current)
• Power-down mode with 550 nA typ current consumption at 5 V

Applications:

• Portable Instrumentation
• PLC Analog Output Module
• Closed-Loop Servo Control
• Voltage Controlled Oscillator Tuning
• Data Acquisition Systems
• Programmable Gain and Offset Adjustment

Package:

• VSSOP-10 (3.00 mm × 3.00 mm body size)
• WSON-10 (3.00 mm × 3.00 mm body size)

• Portable Instrumentation
• PLC Analog Output Module
• Closed-Loop Servo Control
• Voltage Controlled Oscillator Tuning
• Data Acquisition Systems
• Programmable Gain and Offset Adjustment

The DAC756x, DAC816x, and DAC856x devices are low-power, voltage-output, dual-channel, 16-, 14-, and 12-bit digital-to-analog converters (DACs), respectively. These devices include a 2.5-V, 4-ppm/°C internal reference, giving a full-scale output voltage range of 2.5 V or 5 V. The internal reference has an initial accuracy of ±5 mV and can source or sink up to 20 mA at the VREFIN/VREFOUT pin.

These devices are monotonic, providing excellent linearity and minimizing undesired code-to-code transient voltages (glitch). They use a versatile threewire serial interface that operates at clock rates up to 50 MHz. The interface is compatible with standard SPI™, QSPI™, Microwire, and digital signal processor (DSP) interfaces. The DACxx62 devices incorporate a power-on-reset circuit that ensures the DAC output powers up and remains at zero scale until a valid code is written to the device, whereas the DACxx63 devices similarly power up at mid-scale. These devices contain a power-down feature that reduces current consumption to typically 550 nA at 5 V. The low power consumption, internal reference, and small footprint make these devices ideal for portable, battery-operated equipment.

The DACxx62 devices are drop-in and functioncompatible with each other, as are the DACxx63 devices. The entire family is available in MSOP-10 and SON-10 packages.

• (1) TI recommends connecting the thermal pad to the ground plane for better thermal dissipation.

At AVDD = 2.7 V to 5.5 V and TA = -40°C to 125°C (unless otherwise noted).

Over operating ambient temperature range (unless otherwise noted).

over operating ambient temperature range (unless otherwise noted)

$$V_{\text{OUT}} = \frac{R_{\text{G}}}{2} \times \left( \frac{V_{\text{DAC}} - V_{\text{REF}}}{R_{\text{SET}}} \right)$$

When configured for current mode, the XTR300 routes the internal output of its current copy circuitry to the SET pin. This provides feedback for the internal OPA driver based on 1 / 10th of the output current, resulting in a voltage-to-current transfer function. Generating bipolar current outputs from the single-ended DAC output voltage, VDAC, requires the application of an offset to the XTR300 SET pin. Connect the RSET resistor from the SET pin to VREF to apply the offset and obtain the transfer function shown in Equation 6.

$$I_{\mathrm{OUT}} = 10 \times \left(\frac{V_{\mathrm{DAC}} - V_{\mathrm{REF}}}{R_{\mathrm{SET}}}\right)$$

The desired output ranges for VDAC and VREF voltages determine the RSET and RG resistor values, calculated using Equation 7 and Equation 8. The system design requires a VDAC voltage range of 0.04 V to 4.96 V in order to operate the DAC8563 in the specified linear output range from codes 512 to 65 024.

$${\mathrm{R}}{\mathrm{SET}}=10\times\left(\frac{\mathrm{V}{\mathrm{DAC}}-\mathrm{V}{\mathrm{REF}}}{\mathrm{I}{\mathrm{OUT}}}\right)=10\times\left(\frac{4.96\text{ V}-2.5\text{ V}}{0.024\text{ A}}\right)=1025\ \Omega$$

$$R_{\text{G}} = \frac{2 \times V_{\text{OUT_MAX}} \times R_{\text{SET}}}{V_{\text{DAC}} - V_{\text{REF}}} = \frac{2 \times 10\text{ V} \times 1020\ \Omega}{4.96\text{ V} - 2.5\text{ V}} = 8292\ \Omega$$

IMON and IAOUT accomplish load monitoring. The sizing of RIMON and RIA determine the monitoring output voltage across the resistors. Size the resistors according to Equation 9 and Equation 10 and the expected output load current IDRV.

$$R_{\mathrm{IMON}} = \frac{10 \times V_{\mathrm{IMON}}}{I_{\mathrm{DRV}}}$$

$$R_{IA} = \frac{10 \times V_{IA}}{I_{IA}}$$

For more detailed information about the design procedure of this circuit and how to isolate it, see Two-Channel Source/Sink Combined Voltage & Current Output, Isolated, EMC/EMI Tested Reference Design (TIDU434).