LTC2644

1

2644fa

Typical applicaTion

FeaTures

DescripTion

Dual 12-/10-/8-Bit PWM

10ppm/°C Reference

The LTC®2644 is a family of dual 12-, 10-, and 8-bit PWM-

to-voltage output DACs with an integrated high accuracy,

lowdrift,10ppm/°Creferenceina12-leadMSOPpackage.It

hasrail-to-railoutputbuffersandisguaranteedmonotonic.

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/°Cinternalreference.Itcanoperatewithanexternal

reference, which sets the full-scale output equal to the ex-

ternal 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.

PWM Input to DAC Output

2-Channel PWM to Voltage Output DAC

applicaTions

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Digital Calibration

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Trimming and Adjustment

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Level Setting

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Process Control and Industrial Automation

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Instrumentation

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Automotive

L

, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and

ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property

of their respective owners. Protected by U.S. Patents, including 5396245, 5859606, 6891433,

6937178, 7414561.

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No Latency PWM-to-Voltage Conversion

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Voltage Output Updates and Settles within 8µs

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100kHz to 30Hz PWM Input Frequency

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±2.5LSB Max INL; ±1LSB Max DNL (LTC2644-12)

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Guaranteed Monotonic

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Pin-Selectable Internal or External Reference

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2.7V to 5.5V Supply Range

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1.71V to 5.5V Input Voltage Range

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Low Power: 2.7mA at 3V, <1µA Power-Down

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Guaranteed Operation from –40°C to 125°C

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12-Lead MSOP Package

LTC2644

PWM INPUTS

BUFFERED

VOLTAGE

OUTPUTS

GND

PD

0.1µF

1.7V TO 5.5V

2.7V TO 5.5V

GND

IDLSEL

REFSEL

REF

2644 TA01a

0.1µF

0.1µF

INPUT: 1V TO 5.5V

OUTPUT: 1.25V

20µs/DIV

2644TA01b

500mV/DIV

2V/DIV