Convert PWM Inputs to 12-Bit Accurate Voltage Outputs with No Software, No Ripple & No Delay

News Release 
Convert PWM Inputs to 12-Bit Accurate Voltage Outputs with
No Software, No Ripple & No Delay
MILPITAS, CA – August 12, 2014 – Linear Technology Corporation introduces the LTC2645, a
quad-channel 12-bit/10-bit/8-bit PWM-to-voltage output digital-to-analog converter (DAC) with
10ppm/oC reference. These parts convert PWM input signals to 12-bit accurate, stable, buffered
voltage outputs in less than 8µs, eliminating the ripple and delay typically associated with analog
filters. The LTC2645 provides a simple bolt-on solution to accurately set and adjust four voltages
without a single line of code required. Offered in a small 16-lead MSOP package, the LTC2645
is ideal for biasing, calibration, level setting, power supply adjustment, and to enable optoisolated communications in applications such as industrial automation, 4-20mA process control,
instrumentation, test equipment and optical modules. A dual version, the LTC2644, is available
in a 12-lead MSOP package.
The LTC2645 measures the period and pulse width of the PWM input signals and updates
the DACs after each PWM input rising edge, accepting PWM input frequencies from 30Hz up to
100kHz. An IDLSEL pin provides flexibility to set the 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. This convenient mode has the advantage over analog filter implementations,
which require the PWM to run continuously. Each rail-to-rail DAC output is capable of sourcing
or sinking 5mA (3V) or 10mA (5V), and offers a full-scale output of 2.5V using the internal
10ppm/oC reference or a full-scale output equal to the external reference.
Convert PWM Inputs to 12-Bit Accurate Voltage Outputs with
No Software, No Ripple & No Delay
page 2
The LTC2645 operates from a single 2.7V to 5.5V supply, and supports PWM input
voltages from 1.71V to 5.5V. The device consumes just 4mA from a 3V supply, and offers a
<1µA power-down mode with high impedance outputs.
The LTC2645 is offered in 12-bit/10-bit/8-bit versions and is available today in
commercial, industrial and automotive (-40oC to 125oC) temperature grades. Pricing begins at
$3.95 each for the LTC2645-12 in 1,000-piece quantities. The DC2197A evaluation board for the
LTC2645 family is supported by the Linduino™ Firmware Development System, using DC2026
and is available at or via a local Linear Technology sales office. For more
information, visit and
Photo Caption: Quad PWM to Voltage Output DAC
Summary of Features: LTC2645
No Latency PWM-to-Voltage Conversion
Voltage Output Updates & Settles within 8μs
100kHz to 30Hz PWM Input Frequency
±2.5LSB Max INL; ±1LSB Max DNL
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: 4mA at 3V, <1μA Power-Down
–40°C to 125°C Operating Temperature Range
Tiny 4.9mm × 4mm 16-Lead MSOP Package
The USA list pricing shown is for budgetary use only. International prices may differ due to local
duties, taxes, fees and exchange rates.
Convert PWM Inputs to 12-Bit Accurate Voltage Outputs with
No Software, No Ripple & No Delay
page 3
About Linear Technology Linear Technology Corporation, a member of the S&P 500, has been designing, manufacturing and marketing a broad line of high performance analog integrated circuits for major companies worldwide for over three decades. The Company’s products provide an essential bridge between our analog world and the digital electronics in communications, networking, industrial, automotive, computer, medical, instrumentation, consumer, and military and aerospace systems. Linear Technology produces power management, data conversion, signal conditioning, RF and interface ICs, µModule® subsystems, and wireless sensor network products. For more information, visit
, LT, LTC, LTM, Linear Technology, the Linear logo and µModule are registered trademarks and Linduino is a
trademark of Linear Technology Corp. All other trademarks are the property of their respective owners.
Press Contacts:
North America / Worldwide
UK & Nordic
John Hamburger, Director Marketing
Tel: 408-432-1900 ext 2419
Alan Timmins
Tel: +44-1-252-629937
Doug Dickinson, Media Relations Manager
Tel: 408-432-1900 ext 2233