IC ADC W/LCD DRIVER 28-SSOP

MAX1492CAI+T

Manufacturer Part NumberMAX1492CAI+T
DescriptionIC ADC W/LCD DRIVER 28-SSOP
ManufacturerMaxim Integrated Products
MAX1492CAI+T datasheet
 


Specifications of MAX1492CAI+T

Display TypeLCDConfiguration7 Segment + 2 Annunciators
InterfaceSerialDigits Or CharactersA/D 3.5 Digits
Current - Supply960µAVoltage - Supply2.7 V ~ 5.25 V
Operating Temperature0°C ~ 70°CMounting TypeSurface Mount
Package / Case28-SSOPLead Free Status / RoHS StatusLead free / RoHS Compliant
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19-2959; Rev 4; 7/10
3.5- and 4.5-Digit, Single-Chip ADCs
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 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 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 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.
Applications
Digital Panel Meters
Hand-Held Meters
Digital Voltmeters
Digital Multimeters
Pin Configurations appear at end of data sheet.
SPI/QSPI are trademarks of Motorola, Inc.
MICROWIRE is a registered trademark of National
Semiconductor Corp.
________________________________________________________________ Maxim Integrated Products
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.
with LCD Drivers
o High Resolution
MAX1494: 4.5 Digits (±19,999 Count)
MAX1492: 3.5 Digits (±1999 Count)
o Sigma-Delta ADC Architecture
No Integrating Capacitors Required
No Autozeroing Capacitors Required
>100dB of Simultaneous 50Hz and 60Hz
Rejection
o Operate from a Single 2.7V or 5.25V Supply
o Selectable Input Range of ±200mV or ±2V
o Selectable Voltage Reference: Internal 2.048V
or External
o Internal High-Accuracy Oscillator Needs No
External Components
o Automatic Offset Calibration
o Low Power
Maximum 960µA Operating Current
Maximum 400µA Shutdown Current
o Small 32-Pin 7mm x 7mm LQFP Package
(4.5 Digits), 28-Pin SSOP Package (3.5 Digits)
o Triplexed LCD Driver
o SPI-/QSPI-/MICROWIRE-Compatible Serial
Interface
o Evaluation Kit Available (Order MAX1494EVKIT)
Ordering Information/
Selector Guide
TEMP
PIN-
PART
RANGE
PACKAGE
MAX1492CAI+
0°C to +70°C 28 SSOP
MAX1492CNI+
0°C to +70°C 28 PDIP
MAX1494CCJ+
0°C to +70°C 32 LQFP
+ Denotes a lead(Pb)-free/RoHS-compliant package.
Features
RESOLUTION
(DIGITS)
3.5
3.5
4.5
1

MAX1492CAI+T Summary of contents

  • Page 1

    ... Pin Configurations appear at end of data sheet. SPI/QSPI are trademarks of Motorola, Inc. MICROWIRE is a registered trademark of National Semiconductor Corp. ________________________________________________________________ Maxim Integrated Products 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. with LCD Drivers o High Resolution MAX1494: 4.5 Digits (± ...

  • Page 2

    Single-Chip ADCs with LCD Drivers ABSOLUTE MAXIMUM RATINGS AVDD to GND...........................................................-0.3V to +6V DVDD to GND...........................................................-0.3V to +6V AIN+, AIN- to GND ...............................V NEG REF+, REF- to GND ..............................V NEG LOWBATT to GND...................................-0.3V to (AVDD + 0.3V) ...

  • Page 3

    Single-Chip ADCs ELECTRICAL CHARACTERISTICS (continued 2.7V to 5.25V, V AVDD DVDD GND All specifications are MIN MAX PARAMETER SYMBOL Normal-Mode 50Hz and 60Hz Rejection (Simultaneously) Common-Mode ...

  • Page 4

    Single-Chip ADCs with LCD Drivers ELECTRICAL CHARACTERISTICS (continued 2.7V to 5.25V 0V, V AVDD DVDD GND All specifications are MIN MAX PARAMETER SYMBOL CHARGE ...

  • Page 5

    Single-Chip ADCs TIMING CHARACTERISTICS (Notes 10, 11 and Figure 13 2.7V to 5.25V, V AVDD DVDD GND PARAMETER SYMBOL SCLK Operating Frequency SCLK Pulse-Width High SCLK Pulse-Width Low DIN to SCLK Setup DIN ...

  • Page 6

    Single-Chip ADCs with LCD Drivers ( 5V 0V, external reference mode, REF+ = 2.048V, REF- = GND, RANGE bit = 1, internal clock mode, T AVDD DVDD GND +25°C, unless otherwise noted.) ...

  • Page 7

    Single-Chip ADCs ( 5V 0V, external reference mode, REF+ = 2.048V, REF- = GND, RANGE bit = 1, internal clock mode, T AVDD DVDD GND +25°C, unless otherwise noted.) INTERNAL REFERENCE VOLTAGE ...

  • Page 8

    Single-Chip ADCs with LCD Drivers PIN NAME MAX1492 MAX1494 1 30 CLK 2 31 DVDD 3 32 GND 4 1 AVDD 5 2 AIN AIN REF REF LOWBATT EOC ...

  • Page 9

    Single-Chip ADCs PIN NAME MAX1492 MAX1494 24 21 SEG10 25 25 BP3 26 26 BP2 27 27 BP1 NEG — 22 SEG11 — 23 SEG12 — 24 SEG13 — DISP AVDD DVDD ...

  • Page 10

    Single-Chip ADCs with LCD Drivers Detailed Description The MAX1492/MAX1494 low-power, highly integrated ADCs with LCD drivers convert a ±2V differential input voltage (one count is equal to 100µV for the MAX1494 and 1mV for the MAX1492) with ...

  • Page 11

    Single-Chip ADCs ten times the first-notch frequency and 60Hz is equal to 12 times the first-notch frequency. For large step changes at the input, allow a settling time of 800ms before valid data is read. Configure the ...

  • Page 12

    Single-Chip ADCs with LCD Drivers HOLD Figure 4. Backplane Connection for the MAX1494 (4.5 Digits) SEG13: PEAK, HOLD, N.C. HOLD SEG12: F4, E4, DP4 SEG11: A4, G4, D4 SEG10: B4, C4, BC5 SEG9: F3, E3, DP3 Figure ...

  • Page 13

    Single-Chip ADCs HOLD Figure 6. Backplane Connection for the MAX1492 (3.5 Digits) SEG9: F3, E3, DP3 SEG8: A3, G3, D3 Figure 7. Segment Connection for the MAX1492 (3.5 Digits) thus the contrast of the segment. The RMS ...

  • Page 14

    Single-Chip ADCs with LCD Drivers Table 2. Decimal-Point Control Table (MAX1494) DP_EN DPSET1 DPSET2 ...

  • Page 15

    Single-Chip ADCs BP1 BP2 BP3 ALL OFF OFF OFF OFF Figure 9. LCD Voltage Waveform—Combinations 1–4 (BP_, SEG2/5/8) Figure 21 shows the MAX1492/MAX1494 operating with ...

  • Page 16

    Single-Chip ADCs with LCD Drivers BP1 BP2 BP3 ALL OFF OFF OFF OFF φ1, φ2, φ HIGH WITH RESPECT TO SEGMENT (BP+ ...

  • Page 17

    Single-Chip ADCs ALL OFF OFF OFF ALL VOLTAGE CONTRAST RATIO = V φ1, φ2, φ HIGH WITH RESPECT TO SEGMENT (BP+ TIME) φ1', ...

  • Page 18

    Single-Chip ADCs with LCD Drivers 100 Figure 12. Contrast vs. Applied RMS Voltage 18 ______________________________________________________________________________________ Ø = -10° Ø = +10° Ø = -30° Ø = ...

  • Page 19

    Single-Chip ADCs CS t CSS t CSH SCLK DIN t DV DOUT Figure 13. Detailed Timing Diagram CS SCLK 1 0 RS4 RS3 RS2 RS1 DIN CONTROL BYTE DOUT Figure 14. Serial-Interface 16-Bit ...

  • Page 20

    Single-Chip ADCs with LCD Drivers CS SCLK 1 1 RS4 RS3 RS2 RS1 RS0 DIN CONTROL BYTE DOUT Figure 16. Serial-Interface 16-Bit Read Timing Diagram CS SCLK 1 1 RS4 RS3 RS2 RS1 RS0 DIN CONTROL BYTE ...

  • Page 21

    Single-Chip ADCs Applications Information The SPI/QSPI/MICROWIRE serial interface consists of a chip select (CS), a serial clock (SCLK), a data in (DIN), a data out (DOUT), and an asynchronous EOC output. EOC provides an asynchronous end-of-conversion sig- ...

  • Page 22

    Single-Chip ADCs with LCD Drivers Command Byte (Write Only): MSB Bit 7 Bit 6 Bit 5 START (1) R/W RS4 START: Start Bit. The first 1 clocked into the MAX1492/MAX1494 is the first bit of the command ...

  • Page 23

    Single-Chip ADCs SPI/ADC: (Default = 0) Display Select Bit. The SPI/ADC bit controls selection of the data fed into the LCD data register this location selects SPI/QSPI/ MICROWIRE data (the user writes this data ...

  • Page 24

    Single-Chip ADCs with LCD Drivers Table 6. LCD Priority Table SEG_SEL SPI/ADC Don’t care. Overrange Register (Read/Write): MSB D15 D14 D13 D12 D11 Default values: ...

  • Page 25

    Single-Chip ADCs DP1: Segment DP Driver Bit of Digit 1. The default value turns on the LCD segment. E1: Segment e Driver Bit of Digit 1. The default value turns on the LCD segment. F1: Segment f ...

  • Page 26

    Single-Chip ADCs with LCD Drivers LCD Segment-Display Register 3 (Read/Write): MSB PEAK HOLD BC_ Default values: 00h The LCD segment-display register 8-bit read/write register. When the SEG_SEL bit (in the con- trol register) is ...

  • Page 27

    Single-Chip ADCs LCD Data Register (Read/Write): MSB D15 D14 D13 D12 D11 Default values: 0000h The LCD data register is a 16-bit read/write register. This register updates from the ADC result register 1, the PEAK register, or ...

  • Page 28

    Single-Chip ADCs with LCD Drivers Power-On Reset At power-up, the serial interface, LCD driver, digital fil- ter, and modulator circuits reset. The registers return to their default values. Allow time for the reference to set- tle before ...

  • Page 29

    Single-Chip ADCs best performance, ground the MAX1492/MAX1494 to the analog ground plane of the circuit board. Avoid running digital lines under the device because they can couple noise onto the device. Run the analog ground plane under ...

  • Page 30

    Single-Chip ADCs with LCD Drivers ANALOG SUPPLY FERRITE BEAD 0.1µF 4.7µF AVDD REF+ 0.1µF R REF MAX1492 MAX1494 REF- 0.1µF ACTIVE R GAUGE AIN+ 0.1µF AIN- DUMMY 0.1µF GAUGE R GND Figure 20. Strain-Gauge Application with MAX1492/MAX1494 ...

  • Page 31

    Single-Chip ADCs R = 100 Ω 10 0.1µF R 4–20mA 0.1µF Figure 23. 4–20mA Measurement ADC RESULT LCD >4E1Fh 19,999 4E1Fh 2 0002h 1 00001h 0 0000h -0 FFFFh -1 FFFEh -2 ...

  • Page 32

    Single-Chip ADCs with LCD Drivers ADC RESULT LCD >7CFh 1999 7CFh 2 002h 1 001h 000h 0 FFFh -0 -1 FFEh -2 FFDh -1999 830h - <830h -1mV 0 -2V ...

  • Page 33

    Single-Chip ADCs TOP VIEW + CLK 1 DVDD 2 GND 3 AVDD 4 AIN+ 5 MAX1492 AIN- 6 REF- 7 REF+ 8 LOWBATT 9 EOC DIN 12 SCLK 13 DOUT 14 PDIP/SSOP Chip Information ...

  • Page 34

    ... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 34 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2010 Maxim Integrated Products ...