![]() ![]() Several circuit examples are shown in the next section.Īn example of a custom, fixed-gain using the MAX5123's force/sense output is shown in Figure 2. The main drawback is that expensive discrete resistors, resistor arrays, or digital potentiometers are needed to match the gain tolerance and temperature drift characteristics of the fixed-gain DACs.Ī final advantage of the force/sense DAC is it allows many useful circuits to be created with only a few simple external components. The gain error for a force/sense DAC is specified in a unity-gain configuration (op amp output and inverting terminals connected), and additional gain error results from external resistor tolerances. The force/sense type has a further advantage that specific gains can be set externally for a given application. One advantage of the last two DAC types is the offset error can be removed with external circuitry. The drawback is a single, fixed-gain that can only be changed by adding an amplifier after the DAC output. The main advantage of the first two DAC types (Figure 1a and 1b) is the internal resistors are trimmed to provide typical gain error lower than ☑%, and they track each other closely over temperature to provide a typical gain tempco below 10ppm. DAC output types: (a) fixed-gain without offset adjustment, (b) fixed-gain with offset adjustment, (c) force/sense. The final output type is force/sense, which provides a pin connecting directly to the inverting terminal of the output op amp, yielding the most flexibility.įigure 1. The second type also uses internal resistors to set a fixed gain, but the normally grounded resistor tap in the non-inverting gain op amp topology is brought to an external pin allowing offset adjustment. The first has a fixed-gain defined by an internal resistor ratio (typically +1.0, +1.638, or +2.0V/V), and no provision for adjusting the offset. These DACs are interesting because they provide flexibility to create custom DAC gains, or other useful circuits by simply adding a few simple components.įigure 1 shows three common types of buffered, voltage output DACs. A brief description of the various DAC output configurations is also given.įorce/Sense DACs are unique because they provide user access to the inverting node of the output buffer amp in addition to the conventional output. ![]() Applications include: selectable fixed-gain DAC, programmable gain DAC, photodiode bias control, amperometric sensor control, digitally programmable current source, Kelvin load sensing, temperature sensing, and high current DAC output. ![]() Smart DAC LED Biasing Circuit with Low-Power Sleep Mode (Rev.This article discusses application circuits for Maxim force/sense digital-to-analog converters (DACs). Programmable Comparator Circuit Using Second Gen. Negative Voltage Margining and Scaling Circuit With Voltage Output Smart DAC (Rev. View all 13ĭACx3204 12-Bit, 10-Bit, and 8-Bit, Quad Voltage and Current Output Smart DACs With Auto-Detected I2C, PMBus™, or SPI Interface datasheet (Rev. The feature set combined with the tiny package and low power make these smart DACs an excellent choice for applications such as voltage margining and scaling, dc set-point for biasing and calibration, and waveform generation. These devices automatically detect I 2C, PMBus, and SPI interfaces and contain an internal reference. The multifunction GPIO, function generation, and NVM enable these smart DACs for processor-less applications and design reuse. The DAC outputs provide a force-sense option for use as a programmable comparator and current sink. These DACx3204 support Hi-Z power-down mode and Hi-Z output during power-off condition. The 12-bit DAC63204, 10-bit DAC53204, and 8-bit DAC43204 ( DACx3204) are a pin-compatible family of quad-channel, buffered, voltage-output and current-output smart digital-to-analog converters (DACs). Tiny package: 16-pin WQFN (3 mm × 3 mm).Internal, external, or power-supply as reference.User-programmable nonvolatile memory (NVM).Predefined waveform generation: sine wave, triangular, sawtooth.General-purpose input/output (GPIO) configurable as multiple functions.Automatically detected I 2C, PMBus™, or SPI interface.High-impedance and resistive pulldown power-down modes.Programmable comparator mode for all channels.Programmable voltage or current outputs with flexible configuration:. ![]()
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