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

3.5- and 4.5-Digit ADC, LED Display Drivers Reduce Time and Save Board Space

Product Details

The MAX1491/MAX1493/MAX1495 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 ADC is configurable for either a ±2V or ±200mV input range and it outputs its conversion results to an LCD. The MAX1491 is a 3.5-digit (±1999 count) device, and the MAX1493/MAX1495 are 4.5-digit (±19,999 count) devices.

The MAX1491/MAX1493/MAX1495 do not require external-precision integrating or auto-zero 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, the MAX1491/MAX1493/MAX1495 use continuous internal offset calibration, and offer >100dB rejection of 50Hz and 60Hz line noise. The MAX1493/MAX1495 perform enhanced offset calibration at power-up. The MAX1495 also performs enhanced calibration on demand. Other features include data hold and peak hold, and a user programmable low-battery monitor.

The MAX1493/MAX1495 come in a 32-pin 7mm x 7mm TQFP package, and the MAX1491 comes in 28-pin SSOP and 28-pin DIP packages. All devices in this family operate over the 0°C to +70°C commercial temperature range.

Key Features

  • High Resolution
    • MAX1495: 4.5 Digits (±19,999 Count)
    • MAX1493: 4.5 Digits (±19,999 Count)
    • MAX1491: 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 980µA Operating Current
  • Small 32-Pin 7mm x 7mm TQFP Package (4.5 Digits), 28-Pin SSOP Package (3.5 Digits), and 28-Pin DIP Package (3.5 Digits)
  • Triplexed LCD Driver
  • Evaluation Kit Available (Order MAX1494EVKIT)

Applications/Uses

  • Digital Multimeters
  • Digital Panel Meters
  • Digital Voltmeters
  • Handheld meters
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)
$10.82 @1k
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Simplified Block Diagram

MAX1491, MAX1493, MAX1495: Typical Operating Circuit MAX1491, MAX1493, MAX1495: Typical Operating Circuit Zoom icon

Design & Development

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Description

The MAX1493 is a low-power, 4.5-digit analog-to-digital converter (ADC) with integrated liquid-crystal display (LCD) drivers.

The MAX1493 evaluation kit (EV kit) provides a proven printed-circuit board (PCB) layout to facilitate evaluation of the MAX1493 IC. Connect the 4V to 28V DC and ground return to terminal block TB1 (see Figure 1 in the full data sheet).

The EV kit is not a complete digital voltmeter (DVM); additional input scaling and protection circuitry might be required.

This EV kit can also evaluate the MAX1495CCJ+. Contact the factory for free samples. See the Evaluating the MAX1495 section in the full data sheet for additional information.

View Details

Features

  • Reference Design
  • Proven PCB Layout
  • Complete Evaluation System
  • Convenient On-Board Test Points
  • Fully Assembled and Tested

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Support & Training

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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)
$10.82 @1k

Key Features

  • High Resolution
    • MAX1495: 4.5 Digits (±19,999 Count)
    • MAX1493: 4.5 Digits (±19,999 Count)
    • MAX1491: 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 980µA Operating Current
  • Small 32-Pin 7mm x 7mm TQFP Package (4.5 Digits), 28-Pin SSOP Package (3.5 Digits), and 28-Pin DIP Package (3.5 Digits)
  • Triplexed LCD Driver
  • Evaluation Kit Available (Order MAX1494EVKIT)

Applications/Uses

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

Description

The MAX1491/MAX1493/MAX1495 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 ADC is configurable for either a ±2V or ±200mV input range and it outputs its conversion results to an LCD. The MAX1491 is a 3.5-digit (±1999 count) device, and the MAX1493/MAX1495 are 4.5-digit (±19,999 count) devices.

The MAX1491/MAX1493/MAX1495 do not require external-precision integrating or auto-zero 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, the MAX1491/MAX1493/MAX1495 use continuous internal offset calibration, and offer >100dB rejection of 50Hz and 60Hz line noise. The MAX1493/MAX1495 perform enhanced offset calibration at power-up. The MAX1495 also performs enhanced calibration on demand. Other features include data hold and peak hold, and a user programmable low-battery monitor.

The MAX1493/MAX1495 come in a 32-pin 7mm x 7mm TQFP package, and the MAX1491 comes in 28-pin SSOP and 28-pin DIP packages. All devices in this family operate over the 0°C to +70°C commercial temperature range.

Simplified Block Diagram

MAX1491, MAX1493, MAX1495: Typical Operating Circuit MAX1491, MAX1493, MAX1495: 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