IC ADC W/LCD DRIVER 28-DIP

MAX1491CNI+

Manufacturer Part NumberMAX1491CNI+
DescriptionIC ADC W/LCD DRIVER 28-DIP
ManufacturerMaxim Integrated Products
MAX1491CNI+ datasheet
 


Specifications of MAX1491CNI+

Display TypeLCDConfiguration7 Segment + 2 Annunciators
Digits Or CharactersA/D 3.5 DigitsCurrent - Supply980µA
Voltage - Supply2.7 V ~ 5.25 VOperating Temperature0°C ~ 70°C
Mounting TypeThrough HolePackage / Case28-DIP (0.300", 7.62mm)
Lead Free Status / RoHS StatusLead free / RoHS CompliantInterface-
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19-3053; Rev 2; 5/04
General Description
The MAX1491/MAX1493/MAX1495 low-power, 3.5- and
4.5-digit, analog-to-digital converters (ADCs) with inte-
grated liquid crystal display (LCD) drivers operate from a
single 2.7V to 5.25V power supply. They include an inter-
nal 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 config-
urable for either a ±2V or ±200mV input range and it out-
puts 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 exter-
nal-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 continu-
ous internal offset calibration, and offer >100dB rejec-
tion 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
TQFP package, and the MAX1491 comes in 28-pin
SSOP and 28-pin DIP packages. All devices in this fam-
ily operate over the 0°C to +70°C commercial tempera-
ture range.
Digital Panel Meters
Hand-Held Meters
Digital Voltmeters
Digital Multimeters
Ordering Information
TEMP
PIN-
PART
RANGE
PACKAGE
MAX1491CAI
0°C to +70°C 28 SSOP
MAX1491CNI
0°C to +70°C 28 DIP
MAX1493CCJ
0°C to +70°C 32 TQFP
MAX1495CCJ
0°C to +70°C 32 TQFP
________________________________________________________________ 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.
3.5- and 4.5-Digit, Single-Chip
ADCs with LCD Drivers
♦ 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
Digits), 28-Pin SSOP Package (3.5 Digits), and 28-
Pin DIP Package (3.5 Digits)
♦ Triplexed LCD Driver
♦ Evaluation Kit Available (Order MAX1494EVKIT)
7mm
TOP VIEW
Applications
AV
DD
AIN+
AIN-
REF-
REF+
LOWBATT
RANGE
RESOLUTION
DPSET1
(DIGITS)
3.5
3.5
4.5
4.5
Pin Configurations continued at end of data sheet.
Features
7mm TQFP Package (4.5
Pin Configurations
32
31
30
29
28
27
26
25
1
24
2
23
3
22
4
21
MAX1493
5
20
MAX1495
6
19
7
18
8
17
14
9
10
11
12
13
15
16
TQFP
SEG13
SEG12
SEG11
SEG10
SEG9
SEG8
SEG7
SEG6
1

MAX1491CNI+ Summary of contents

  • Page 1

    ... DIP MAX1493CCJ 0°C to +70°C 32 TQFP MAX1495CCJ 0°C to +70°C 32 TQFP ________________________________________________________________ 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. 3.5- and 4.5-Digit, Single-Chip ADCs with LCD Drivers ♦ ...

  • Page 2

    Single-Chip ADCs with LCD Drivers ABSOLUTE MAXIMUM RATINGS AV to GND............................................................-0. GND ...........................................................-0.3V to +6V DD AIN+, AIN- to GND...............................V REF+, REF- to GND..............................V LOWBATT to GND ...................................-0.3V to (AV INTREF, RANGE, ...

  • Page 3

    ELECTRICAL CHARACTERISTICS (continued) ( +2.7V to +5.25V, GND = unless otherwise noted. Typical values are at +25°C, unless otherwise noted.) MAX PARAMETER SYMBOL LOW-BATTERY VOLTAGE MONITOR (LOWBATT) LOWBATT Trip Threshold ...

  • Page 4

    Single-Chip ADCs with LCD Drivers ELECTRICAL CHARACTERISTICS (continued) ( +2.7V to +5.25V, GND = unless otherwise noted. Typical values are at +25°C, unless otherwise noted.) MAX PARAMETER ...

  • Page 5

    DV = 5V, GND = 0, REF+ = 2.048V, REF- = GND, RANGE = MAX1493/MAX1495 (±200mV INPUT RANGE) INL vs. DISPLAY COUNT 1.0 0.5 0 -0.5 -1.0 -20,000 -10,000 0 10,000 20,000 DISPLAY COUNT SUPPLY ...

  • Page 6

    Single-Chip ADCs with LCD Drivers ( 5V, GND = 0, REF+ = 2.048V, REF- = GND, RANGE = INTERNAL REFERENCE VOLTAGE vs. TEMPERATURE 2.054 2.053 2.052 2.051 2.050 2.049 2.048 2.047 ...

  • Page 7

    PIN NAME MAX1493 MAX1491 MAX1495 Internal Reference Logic Input. Connect to GND to select external reference mode. Connect 1 30 INTREF to DV Digital Power Input. Connect with a 0.1µF and a 4.7µF capacitor. 3 ...

  • Page 8

    Single-Chip ADCs with LCD Drivers PIN NAME MAX1493 MAX1491 MAX1495 21 18 SEG7 LCD Segment 7 Driver 22 19 SEG8 LCD Segment 8 Driver 23 20 SEG9 LCD Segment 9 Driver 24 21 SEG10 LCD Segment 10 ...

  • Page 9

    Detailed Description The MAX1491/MAX1493/MAX1495 low-power, highly integrated ADCs with LCD drivers convert a ±2V differ- ential input voltage (one count is equal to 100µV for the MAX1493/MAX1495 and 1mV for the MAX1491) with a sigma-delta ADC and output the result ...

  • Page 10

    Single-Chip ADCs with LCD Drivers The MAX1491/MAX1493/MAX1495 contain an internal oscillator. Using the internal oscillator saves board space by removing the need for an external clock source. The oscillator is optimized to give 50Hz and 60Hz power ...

  • Page 11

    HOLD Figure 4. Backplane Connection for the MAX1493/MAX1495 (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 SEG8: A3, G3, D3 Figure 5. Segment Connection for ...

  • Page 12

    Single-Chip ADCs with LCD Drivers HOLD Figure 6. Backplane Connection for the MAX1491 (3.5 Digits) SEG10: PEAK, HOLD, BC4 SEG9: F3, E3, DP3 SEG8: A3, G3, D3 Figure 7. Segment Connection for the MAX1491 (3.5 Digits) X ...

  • Page 13

    BP1 BP2 BP3 ALL OFF OFF OFF OFF φ1, φ2, φ HIGH WITH RESPECT TO SEGMENT (BP+ TIME) φ1', φ2', φ LOW ...

  • Page 14

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

  • Page 15

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

  • Page 16

    Single-Chip ADCs with LCD Drivers 100 Figure 12. Contrast vs. Applied RMS Voltage 16 ______________________________________________________________________________________ Ø = -10°C Ø = +10°C Ø = -30°C Ø = 0°C V ...

  • Page 17

    If ghosting is present on the LCD, the RMS OFF voltage is too high. Choose an LCD with a higher RMS OFF voltage or decrease Decimal Point Control The MAX1491/MAX1493/MAX1495 allow for full deci- mal-point control and ...

  • Page 18

    Single-Chip ADCs with LCD Drivers offers enhanced offset calibration on demand. Connect HOLD to DV for 2s to perform enhanced offset cali- DD bration. The MAX1491/MAX1493/MAX1495 feature peak detec- tion circuitry. When activated (PEAK connected to DV ...

  • Page 19

    Transfer Functions Figures 15–18 show the MAX1491/MAX1493s’ transfer functions. The transfer function for the MAX1493/ MAX1495 with AIN+ - AIN- ≥ 0 and RANGE = GND is: ⎛ AIN = × Counts 1 024 . ⎜ ...

  • Page 20

    Single-Chip ADCs with LCD Drivers LCD 1999 -1999 - -100µV 100µV 0 -200mV ANALOG INPUT VOLTAGE Figure 17. MAX1491 Transfer ...

  • Page 21

    Gain error is the amount of deviation between the mea- sured full-scale transition point and the ideal full-scale transition point. Common-Mode Rejection Common-mode rejection is the ability of a device to reject a signal that is common to both input ...

  • Page 22

    Single-Chip ADCs with LCD Drivers Pin Configurations (continued) TOP VIEW INTREF GND AIN+ 5 MAX1491 AIN- 6 REF- 7 REF+ 8 LOWBATT 9 RANGE 10 DPSET1 11 DPSET2 12 ...

  • Page 23

    For the latest package outline information go to www.maxim-ic.com/packages.) ______________________________________________________________________________________ 3.5- and 4.5-Digit, Single-Chip ADCs with LCD Drivers Package Information 23 ...

  • Page 24

    Single-Chip ADCs with LCD Drivers (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages NOTES: 1. D&E ...

  • Page 25

    ... 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 25 © 2004 Maxim Integrated Products 3 ...