ICL7117CPL+3

ADCs/DACs - Special Purpose Overview

The ICL7117CPL+3 is a 3½ digit monolithic analog-to-digital converter (ADC) manufactured by Analog Devices Inc./Maxim Integrated. It features a dual-slope conversion technique with a dedicated Hold pin to freeze readings, eliminating overrange hangover and hysteresis effects. The device directly drives LED displays without external circuitry, utilizing high-impedance CMOS differential inputs. Key electrical parameters include a maximum clock frequency of 48 kHz, a power supply range of +6V to -9V for the ICL7117 variant, and a typical power dissipation of 800 mW in plastic packages.

ADCs/DACs - Special Purpose Feature Summary

• Integrated Display Hold Pin: Allows indefinite freezing of the display reading while conversions continue internally.
• Direct LED Drive Capability: Includes on-board segment decoders and drivers for direct connection to LED displays.
• Dual-Slope Conversion: Automatically rejects common-mode interference signals typical in industrial environments.
• High Accuracy Specifications: Features rollover error less than one count and zero reading drift below 1µV/°C.

ADCs/DACs - Special Purpose Applications

• Digital panel meters
• Precision null detection applications
• Ratiometric measurements using bridge transducers
• Measurement and display of analog data such as pressure, voltage, resistance, temperature, conductance, current, speed, and material thickness

ADCs/DACs - Special Purpose Procurement Notes

Verify the specific suffix '+3' against official manufacturer documentation to confirm packaging details, as standard listings may indicate tube packaging for PDIP variants. Confirm availability status through authorized distributors, as this component may be subject to limited supply or discontinuation notices. Ensure the ordering information matches the required temperature range and package type for the intended application.

ADCs/DACs - Special Purpose Selection Notes

Select the ICL7117CPL+3 when an LED display interface is required, distinguishing it from the LCD-specific ICL7116. The device requires a dual power supply configuration (+6V to V+ and -9V to GND). Designers must account for the internal pull-down resistor on the Hold pin and ensure the reference voltage is applied between REF HI and Common, as there is no Reference Low input.

ADCs/DACs - Special Purpose Part Context

The ICL7117 series differs from the earlier ICL7107 model primarily by the inclusion of a digital Hold input, enabling the display to be frozen without interrupting the conversion cycle. This addition eliminates overrange hangover and hysteresis effects found in previous generations. The CPL+ designation indicates a lead-free, RoHS-compliant Plastic Dual In-Line Package (PDIP) with 40 pins.

ADCs/DACs - Special Purpose Replacement Considerations

The ICL7117CPL is a direct functional equivalent within the same family. For non-Hold applications, the ICL7107 serves as a compatible alternative, though it lacks the display freeze feature. Verify that any substitute supports the required LED drive current and dual-supply voltage specifications.

ADCs/DACs - Special Purpose FAQ

How does the Hold pin function on the ICL7117?

The Hold pin inhibits the display latch pulse when connected to V+, freezing the display while the ADC continues conversions. It has an internal 70kΩ pull-down resistor to ground, so leaving it open results in a low state where the display updates after each conversion.

What are the power supply requirements for the ICL7117?

The ICL7117 requires a dual power supply. The positive supply (V+) ranges up to +6V relative to ground, and the negative supply (V-) ranges down to -9V relative to ground.

Does the ICL7117 have a Reference Low input?

No, unlike the ICL7106/ICL7107, the ICL7116/ICL7117 do not have a Reference Low input. The reference voltage must be applied between the Reference High (REF HI) pin and the Common pin.