Summary of LTC2645 – Quad 12-/10-/8-Bit PWM to VOUT DACs with 10ppm/°C Reference
The LTC2645 is a quad PWM-to-voltage DAC family (12/10/8-bit) with an integrated 10ppm/°C reference, rail-to-rail outputs, and guaranteed monotonicity. It converts PWM inputs (100kHz–30Hz) with no latency, updating outputs to 12-bit accuracy within 8 μs, and can source/sink up to 5 mA (3V) or 10 mA (5V). Features include pin-selectable internal/external reference, wide supply (2.7–5.5V) and input (1.71–5.5V) ranges, low power operation, and operation from −40°C to 125°C in a 16-lead MSOP.
Parts used in the LTC2645 Project:
- LTC2645 quad PWM-to-voltage DAC (12/10/8-bit)
- Integrated 10ppm/°C reference (on LTC2645)
- 16-lead MSOP package
- External reference pin (optional external reference component)
- Power supply (2.7V to 5.5V)
- PWM signal source (100kHz to 30Hz)
- Output load capable of up to 5mA (3V) or 10mA (5V)
- Optional power-down control (for <1μA power-down)
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 (LTC2645-12)
- 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: 4mA at 3V, <1μA Power-Down
- Guaranteed Operation from –40°C to 125°C
- 16-Lead MSOP Package
Typical Application
Description
The LTC®2645 is a family of quad 12-, 10-, and 8-bit PWMto- voltage output DACs with an integrated high accuracy, low drift, 10ppm/°C reference in a 16-lead MSOP package. It has rail-to-rail output buffers and is guaranteed monotonic.
The LTC2645 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.
For more detail: LTC2645 – Quad 12-/10-/8-Bit PWM to VOUT DACs with 10ppm/°C Reference
- What is the input PWM frequency range for the LTC2645?
The LTC2645 accepts PWM input frequencies from 100kHz down to 30Hz. - How fast do the DAC outputs update and settle?
The DAC outputs update and settle to 12-bit accuracy within 8 microseconds typically after the PWM rising edge. - Does the LTC2645 include an internal reference?
Yes, the LTC2645 includes an integrated high accuracy 10ppm/°C reference and also allows a pin-selectable external reference. - What supply voltage range does the LTC2645 support?
The LTC2645 supports a supply range of 2.7V to 5.5V. - What input voltage range is supported for PWM signals?
The input voltage range for PWM signals is 1.71V to 5.5V. - What are the output drive capabilities of the LTC2645?
The outputs can source and sink up to 5mA at 3V or 10mA at 5V. - What power consumption can be expected and is there a power-down mode?
Typical supply current is 4mA at 3V, and a power-down mode reduces current to less than 1 microamp. - What temperature range is the LTC2645 guaranteed to operate over?
The LTC2645 is guaranteed to operate from −40°C to 125°C. - Is the LTC2645 monotonic and what are its INL/DNL specs?
The LTC2645 is guaranteed monotonic; the LTC2645-12 version specifies ±2.5LSB max INL and ±1LSB max DNL.
