1. Overview & Type

️· The LTC1290 is an ADC. (This is the most basic piece of information)

2. Operating Conditions & Key Specs

️· Supply Voltage: VCC = 5V is the common operating voltage.
️· Reference Voltages: VREF [+] = 5V, V REF [–] = 0V (for unipolar mode) or -5V (for bipolar mode).
️· Resolution: 4096 steps.
️· ADC Clock Frequency: ACLK = 4.0MHz is recommended.
️· Temperature Range: Specifications are shown with TA = 25°C, but functionality extends to other temperatures (with varying behaviors – see note about leakage currents).

3. Electrical Characteristics (Highlights)


️· Input Voltages:
- VIH (High Level Input Voltage): 2.0V
- VIL (Low Level Input Voltage): 0.8V
️· Input Currents:
- IIH (High Level Input Current): 2.5µA
- IIL (Low Level Input Current): –2.5µA
️· Output Voltages:
- VOH (High Level Output Voltage): Varies with load, but typically 4.7V (or lower with high load)
- VOL (Low Level Output Voltage): 0.4V
️· Output Leakage:
- IOZ (High-Z Output Leakage): 3µA (to VCC), –3µA (to ground)
️· Output Currents:
- ISOURCE (Output Source Current): –20mA
- ISINK (Output Sink Current): 20mA
️· Supply Currents:
- ICC (Positive Supply Current): 6mA (CS High), 5-10µA in power shutdown.
- IREF (Reference Current): 10-50µA
- I– (Negative Supply Current): 1-50µA
️· Offset Voltage: Unadjusted offset voltage is 0.2mV at 25°C, and 0.125mV.

4. Important Notes & Considerations

️· Bipolar vs. Unipolar: The ADC can operate in either unipolar (single-ended, 0 to VREF) or bipolar mode (two’s complement).
️· Input Diode Protection: Two diodes are connected to the analog and reference inputs. You must be careful to avoid forward-biasing these diodes, especially at low supply voltages. A maximum forward bias of 50 mV is allowed.
️· Clock Frequency & Temperature: Leakage currents increase with temperature, so higher ACLK frequencies are needed at higher temperatures to prevent S/H droop.
️· Chip Select Timing: The chip requires a setup time of two falling edges of the ACLK signal after the falling edge of the chip select signal.
️· Power Shutdown: The ADC has a power-down mode to reduce power consumption.

5. Typical Performance (Brief Description)

The document includes typical performance characteristics graphs, depicting:

️· Unadjusted Offset Voltage vs. Supply Voltage: Illustrates the relationship between offset voltage and supply voltage.
️· Supply Current vs. Supply Voltage: Shows the dependency of supply current on supply voltage.
️· Supply Current vs. Temperature: Demonstrates the influence of temperature on supply current.
️· Reference Voltage vs. Temperature: Portrays how the reference voltage changes with temperature.