Electronicdesign 7638 0820npdtltc2

Convert PWM Inputs to 12-Bit Voltage Outputs Without Ripple or Delay

Aug. 20, 2014
The LTC2645 converts pulse-width-modulation (PWM) input signals to 12-bit accurate, stable buffered voltage outputs in less than 8 µs, thus removing the ripple and delay often plaguing analog filters.

The LTC2645 converts pulse-width-modulation (PWM) input signals to 12-bit accurate, stable buffered voltage outputs in less than 8 µs, thus removing the ripple and delay often plaguing analog filters. Developed by Linear Tech, the quad-channel, 12-/10-/8-bit digital-to-analog converter (DAC) with 10-ppm/°C reference offers a bolt-on solution to accurately set and adjust four voltages without requiring a single line of code. It measures the period and pulse width of PWM input signals and updates the DACs after each PWM input rising edge, accepting PWM input frequencies from 30 Hz up to 100 kHz. An IDLSEL pin makes it possible to set outputs to idle at zero- or full-scale, power down with high-impedance output, or hold the previous state indefinitely in response to an idle PWM input. Each rail-to-rail DAC output can source or sink 5 mA (3 V) or 10 mA (5 V). Operation is from a single 2.7- to 5.5-V supply, and supports PWM input voltages from 1.71 to 5.5 V. Its 4-mA power consumption comes from a 3-V supply. It comes in a 16-lead MSOP package; a dual version (LTC2644) comes in a 12-lead MSOP.

LINEAR TECHNOLOGY CORP.

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