LTC2440IGN#TRPBF

The LTC2440 is a high speed 24-bit No Latency ΔΣ ADC with 5ppm INL and 5uV offset. It uses a proprietary delta-sigma architecture enabling variable speed and resolution with no latency. Ten speed/resolution combinations (6.9Hz/200nVRMS to 3.5kHz/25uVRMS) are programmed through a simple serial interface. Alternatively, by tying a single pin HIGH or LOW, a fast (880Hz/2uVRMS) or ultralow noise (6.9Hz, 200nVRMS, 50/60Hz rejection) speed/resolution combination can be easily selected. The accuracy (offset, full-scale, linearity, drift) and power dissipation are independent of the speed selected. Since there is no latency, a speed/resolution change may be made between conversions with no degradation in performance. Following each conversion cycle, the LTC2440 automatically enters a low power sleep state. Power dissipation may be reduced by increasing the duration of this sleep state. For example, running at the 3.5kHz conversion speed but reading data at a 100Hz rate draws 240uA average current (1.1mW) while reading data at a 7Hz output rate draws only 25uA (125uW). The LTC2440 communicates through a flexible 3-wire or 4-wire digital interface that is compatible with the LTC2410 and is available in a narrow 16-lead SSOP package.

Applications

• High Speed Multiplexing
• Weight Scales
• Auto Ranging 6-Digit DVMs
• Direct Temperature Measurement
• High Speed Data Acquisition

Key features

• Up to 3.5kHz Output Rate (External f0)
• Selectable Speed/Resolution
• 2uVRMS Noise at 880Hz Output Rate
• 200nVRMS Noise at 6.9Hz Output Rate with Simultaneous 50/60Hz Rejection
• 0.0005% INL, No Missing Codes
• Autosleep Enables 20uA Operation at 6.9Hz
• <5uV Offset (4.5V < Vcc < 5.5V, -40°C to 85°C)
• Differential Input and Differential Reference with GND to Vcc Common Mode Range
• No Latency, Each Conversion is Accurate Even After an Input Step
• Internal Oscillator—No External Components
• Pin Compatible with the LTC2410
• 24-Bit ADC in Narrow 16-Lead SSOP Package