General Description
The MAX136 is a monolithic analog-to-digital converter (
ADC) with very high input impedance. It differs from the Maxim ICL7136 in that the MAX136 provides a Hold pin, which makes it possible to hold or "freeze" a reading. The MAX136 directly drives a nonmultiplexed liquid crystal (
LCD) display, requiring no external drive circuitry. With minor external component changes, it is pin compatible with the ICL7116 but with significantly reduced power consumption, making the MAX136 a superior device for portable systems.
Versatility and accuracy are inherent features of this ADC. The dual-slope conversion technique automatically rejects interference signals common in industrial environments. True differential inputs allow direct measurements of bridge transducer outputs or load cells. The zero-integrator phase eliminates overrange hangover and hysteresis effects. The MAX136 offers high accuracy by lowering rollover error to less than one count and zero reading drift to less than 1µV/°C.
Features
• Power Dissipation Guaranteed Less than 1mW–9V
Battery Life 3000 Hours Typical
• Hold Pin Allows Indefinite Display Hold
• Guaranteed First Reading Recovery from Overrange
• On-Board Display Drive Capability—No External Circuitry Required
• High-Impedance CMOS Differential Inputs
• Low Noise(< 15µVP-P) Without Hysteresis or Overrange Hangover
• Clock and Reference On-Chip
• Zero Input Gives Zero Reading
• True Polarity Indication for Precision Null Applications
• Key Parameters Guaranteed Over Temperature
Applications
These devices can be used in a wide range of digital panel meter applications. Most applications, however, involve the measurement and display of analog data:
Pressure
Voltage
Resistance
Temperature
Conductance
Current
Speed
Material Thickness