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3.5- and 4.5-Digit, Single-Chip ADCs with LCD Drivers

Product Details

Key Features

Parametric specs for Display-Oriented ADCs
Resolution (±Counts) 20000
# Input Channels 1
Conv. Rate (ksps) (max) 0.0025
Data Bus 7-Segment
Diff/S.E. Input Diff. Only
Internal VREF (V) (nominal) 2.048
External VREF (V) (min) 0
External VREF (V) (max) 2.048
Bipolar VIN (±V) (max) 2
INL (±LSB) 1
Package/Pins LQFP/32
Budgetary
Price (See Notes)
11.47
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Simplified Block Diagram

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Parameters

Parametric specs for Display-Oriented ADCs
Resolution (±Counts) 20000
# Input Channels 1
Conv. Rate (ksps) (max) 0.0025
Data Bus 7-Segment
Diff/S.E. Input Diff. Only
Internal VREF (V) (nominal) 2.048
External VREF (V) (min) 0
External VREF (V) (max) 2.048
Bipolar VIN (±V) (max) 2
INL (±LSB) 1
Package/Pins LQFP/32
Budgetary
Price (See Notes)
11.47

Key Features

  • High Resolution
    • MAX1494: 4.5 Digits (±19,999 Count)
    • MAX1492: 3.5 Digits (±1999 Count)
  • Sigma-Delta ADC Architecture
    • No Integrating Capacitors Required
    • No Autozeroing Capacitors Required
    • > 100dB of Simultaneous 50Hz and 60Hz Rejection
  • Operate from a Single 2.7V or 5.25V Supply
  • Selectable Input Range of ±200mV or ±2V
  • Selectable Voltage Reference: Internal 2.048V or External
  • Internal High-Accuracy Oscillator Needs No External Components
  • Automatic Offset Calibration
  • Low Power
    • Maximum 960µA Operating Current
    • Maximum 400µA Shutdown Current
  • Small 32-Pin 7mm x 7mm LQFP Package (4.5 Digits), 28-Pin SSOP Package (3.5 Digits)
  • Triplexed LCD Driver
  • SPI-/QSPI-/MICROWIRE-Compatible Serial Interface
  • Evaluation Kit Available (Order MAX1494EVKIT)

Applications/Uses

  • Digital Multimeters
  • Digital Panel Meters
  • Digital Voltmeters
  • Handheld meters

Description

The MAX1492/MAX1494 low-power, 3.5- and 4.5-digit, analog-to-digital converters (ADCs) with integrated liquid crystal display (LCD) drivers operate from a single 2.7V to 5.25V power supply. They include an internal reference, a high-accuracy on-chip oscillator, and a triplexed LCD driver. An internal charge pump generates the negative supply needed to power the integrated input buffer for single-supply operation. The ADCs are configurable for either a ±2V or ±200mV input range and outputs its conversion results to an LCD and/or to a microcontroller (µC). µC communication is facilitated through an SPI™-/QSPI™-/MICROWIRE®-compatible serial interface. The MAX1492 is a 3.5-digit (±1999 count) device, and the MAX1494 is a 4.5-digit (±19,999 count) device.

The MAX1492/MAX1494 do not require external-precision integrating capacitors, autozero capacitors, crystal oscillators, charge pumps, or other circuitry required with dual-slope ADCs (commonly used in panel meter circuits).

These devices also feature on-chip buffers for the differential signal and reference inputs, allowing direct interface with high-impedance signal sources. In addition, they use continuous internal-offset calibration and offer > 100dB simultaneous rejection of 50Hz and 60Hz line noise. Other features include data hold and peak hold, overrange and underrange detection, and a low-battery monitor.

The MAX1494 comes in a 32-pin, 7mm x 7mm LQFP package, and the MAX1492 comes in 28-pin SSOP and 28-pin PDIP packages. All devices in this family operate over the 0°C to +70°C commercial temperature range.

Simplified Block Diagram

MAX1492, MAX1494: Typical Operating Circuit MAX1492, MAX1494: Typical Operating Circuit Zoom icon

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .