Rainbow Electronics MAX1494 - Manual

General 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 refer-
ence, a high-accuracy on-chip oscillator, and a triplexed
LCD driver. An internal charge pump generates the neg-
ative 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 outputs its con-
version results to an LCD and/or to a microcontroller
(µC). µC communication is facilitated through an
SPI™-/QSPI™-/MICROWIRE™-compatible serial inter-
face. 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-preci-
sion 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 dif-
ferential signal and reference inputs, allowing direct
interface with high-impedance signal sources. In addi-
tion, 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 TQFP
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.
Applications
Digital Panel Meters
Hand-Held Meters
Digital Voltmeters
Digital Multimeters
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 TQFP 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)
MAX1492/MAX1494
3.5- and 4.5-Digit, Single-Chip ADCs
with LCD Drivers
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-2959; Rev 3; 5/04
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
EVALUATION KIT
AVAILABLE
PART
TEMP
RANGE
PIN-
PACKAGE RESOLUTION
(DIGITS)
MAX1492CAI 0 °C to +70°C 28 SSOP 3.5
MAX1492CNI 0 °C to +70°C 28 PDIP 3.5
MAX1494CCJ 0 °C to +70°C 32 TQFP 4.5
SPI/QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
Pin Configurations appear at end of data sheet.