Features

• No Latency PWM-to-Voltage Conversion
• Voltage Output Updates and Settles within 8μs
• 100kHz to 30Hz PWM Input Frequency
• ±2.5LSB Max INL; ±1LSB Max DNL (LTC2644-12)
• Guaranteed Monotonic
• Pin-Selectable Internal or External Reference
• 2.7V to 5.5V Supply Range
• 1.71V to 5.5V Input Voltage Range
• Low Power: 2.7mA at 3V, <1μA Power-Down
• Guaranteed Operation from –40°C to 125°C
• 12-Lead MSOP Package

Typical Application

Description

The LTC®2644 is a family of dual 12-, 10-, and 8-bit PWMto- voltage output DACs with an integrated high accuracy, low drift, 10ppm/°C reference in a 12-lead MSOP package. It has rail-to-rail output buffers and is guaranteed monotonic.

The LTC2644 measures the period and pulse width of the PWM input signals and updates the voltage output DACs after each corresponding PWM input rising edge. The DAC outputs update and settle to 12-bit accuracy within 8μs typically and are capable of sourcing and sinking up to 5mA (3V) or 10mA (5V), eliminating voltage ripple and replacing slow analog filters and buffer amplifiers.

The LTC2644 has a full-scale output of 2.5V using the 10ppm/°C internal reference. It can operate with an external reference, which sets the full-scale output equal to the external reference voltage. Each DAC enters a pin-selectable idle state when the PWM input is held unchanged for more than 60ms. The part operates from a single 2.7V to 5.5V supply and supports PWM input voltages from 1.71V to 5.5V.