LTC2668 16-Channel, 16-/12-Bit Voltage Output DACs

LTC2668 16-Channel, 16-/12-Bit Voltage Output DACs

Linear Technology's 16-, 12-bit LTC2668 combines sixteen voltage output DACs with five software-programmable (SoftSpan) or pin-configurable output voltage ranges up to ±10 V. Each output span is independently selectable per channel, with full 16-, 12-bit resolution at all spans. Tight DC linearity with low AC and DC crosstalk ensures precision control in multichannel open or closed-loop systems. Additional features include an internal 16:1 analog multiplexer for calibration or monitoring circuit integrity, and a toggle function that allows the DAC to quickly toggle between two DAC codes.

Video: 16-Channel, 16/12-Bit Voltage Output DACs in a Tiny 6 mm x 6 mm Package

LTC2668 Typical Application

Features

  • 16 DACs in small 6 mm × 6 mm QFN package
  • Internal precision reference: 10 ppm/°C (max.)
  • Independently programmable output ranges: 0 V to 5 V, 0 V to 10 V, ±2.5 V, ±5 V, ±10 V
  • Maximum INL error: ±4 LSB (16-bits), ±1 LSB (12-bits)
  • Flexible single- or dual-supply operation
  • Guaranteed monotonic overtemperature
  • Output buffers drive ±10 mA and 1000 pF loads
  • A/B toggle via software or dedicated pin
  • Internal 16:1 analog MUX
  • Asynchronous DAC update pin
  • 1.8 V to 5 V SPI serial interface
  • -40°C to 125°C operation

Flexible supply voltages

  • V+ positive rail
    • 4.5 V to 15.75 V
    • 4.6 mA operating, 35 μA shutdown
  • V negative rail
    • Single supply: connect to GND
    • Dual supply: –4.5 V to –15.75 V
    • 4.6 mA operating, 27 μA shutdown
  • AVP DAC core supply
    • 4.5 V to 5.5 V
    • 5.4 mA operating, 1 μA shutdown
  • OVP digital I/O supply
    • 1.71 V to 5.5 V
    • <1 μA

Internal 16:1 analog MUX

  • Connect any DAC output to the MUX pin
  • Eliminates high pin count external MUX
  • Saves board space
  • Use this function for:
    • Calibration
    • Closed-loop control
    • Monitor circuit integrity
  • Output range: V to (V+ –1.4 V)

Buffered voltage outputs

  • Rail-to-rail outputs
    • ±10 mA load, swings within 1.4 V of rails
    • Unloaded, swings within 10 mV of rails
  • Fast settling
    • 5 V/μs slew rate
    • 10 V step settles to 1 LSB in 9 μs
  • Stable with up to 1000 pF of load

A/B toggle function

  • Quickly toggle between two DAC codes
    • Hardware mode using TGP pin
    • Software mode using SPI
  • Use this function to:
    • Alternate between two output levels (On / Off, High / Low)
    • Dither or modulate a DC bias level
    • Generate an AC bias

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