MAX1492/MAX1494 19-2959 Rev 4 7/10 3.5- and 4.5-Digit, Single-Chip ADCs with LCD Drivers General Description Features The MAX1492/MAX1494 low-power, 3.5- and 4.5-digit, High Resolution analog-to-digital converters (ADCs) with integrated liquid MAX1494: 4.5 Digits (19,999 Count) crystal display (LCD) drivers operate from a single 2.7V MAX1492: 3.5 Digits (1999 Count) to 5.25V power supply. They include an internal refer- Sigma-Delta ADC Architecture ence, a high-accuracy on-chip oscillator, and a triplexed LCD driver. An internal charge pump generates the neg- No Integrating Capacitors Required ative supply needed to power the integrated input buffer No Autozeroing Capacitors Required for single-supply operation. The ADCs are configurable >100dB of Simultaneous 50Hz and 60Hz for either a 2V or 200mV input range and outputs its Rejection conversion results to an LCD and/or to a microcontroller Operate from a Single 2.7V or 5.25V Supply (C). C communication is facilitated through an SPI-/QSPI-/MICROWIRE -compatible serial inter- Selectable Input Range of 200mV or 2V face. The MAX1492 is a 3.5-digit (1999 count) device, Selectable Voltage Reference: Internal 2.048V and the MAX1494 is a 4.5-digit (19,999 count) device. or External The MAX1492/MAX1494 do not require external-preci- sion integrating capacitors, autozero capacitors, crystal Internal High-Accuracy Oscillator Needs No oscillators, charge pumps, or other circuitry required External Components with dual-slope ADCs (commonly used in panel meter Automatic Offset Calibration circuits). Low Power These devices also feature on-chip buffers for the dif- ferential signal and reference inputs, allowing direct Maximum 960A Operating Current interface with high-impedance signal sources. In addi- Maximum 400A Shutdown Current tion, they use continuous internal-offset calibration and Small 32-Pin 7mm x 7mm LQFP Package offer >100dB simultaneous rejection of 50Hz and 60Hz (4.5 Digits), 28-Pin SSOP Package (3.5 Digits) line noise. Other features include data hold and peak hold, overrange and underrange detection, and a low- Triplexed LCD Driver battery monitor. SPI-/QSPI-/MICROWIRE-Compatible Serial The MAX1494 comes in a 32-pin, 7mm x 7mm LQFP Interface package, and the MAX1492 comes in 28-pin SSOP and Evaluation Kit Available (Order MAX1494EVKIT) 28-pin PDIP packages. All devices in this family operate over the 0C to +70C commercial temperature range. Ordering Information/ Selector Guide Applications Digital Panel Meters TEMP PIN- RESOLUTION PART RANGE PACKAGE (DIGITS) Hand-Held Meters MAX1492CAI+ 0C to +70C 28 SSOP 3.5 Digital Voltmeters MAX1492CNI+ 0C to +70C 28 PDIP 3.5 Digital Multimeters MAX1494CCJ+ 0C to +70C 32 LQFP 4.5 +Denotes a lead(Pb)-free/RoHS-compliant package. 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 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLE3.5- and 4.5-Digit, Single-Chip ADCs with LCD Drivers ABSOLUTE MAXIMUM RATINGS AVDD to GND...........................................................-0.3V to +6V Continuous Power Dissipation (T = +70C) A DVDD to GND...........................................................-0.3V to +6V 28-Pin SSOP (derate 14.9mW/C above +70C) ....1192.3mW AIN+, AIN- to GND ...............................V to +(AVDD + 0.3V) 28-Pin PDIP (derate 14.3mW/C above +70C)......1142.9mW NEG REF+, REF- to GND..............................V to +(AVDD + 0.3V) 32-Pin LQFP (derate 20.7mW/C above +70C).....1652.9mW NEG LOWBATT to GND...................................-0.3V to (AVDD + 0.3V) Operating Temperature Range...............................0C to +70C CLK, EOC, CS, DIN, SCLK, DOUT to Junction Temperature......................................................+150C GND ....................................................-0.3V to (DVDD + 0.3V) Storage Temperature Range .............................-60C to +150C SEG and BP to GND............................-0.3V to (DVDD + 0.3V) Lead Temperature (soldering, 10s) .................................+300C V to GND...........................................-2.6V to (AVDD + 0.3V) Soldering Temperature (reflow) .......................................+260C NEG V to GND ..........................................-0.3V to (DVDD + 0.3V) DISP Maximum Current into Any Pin ...........................................50mA Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V = V = 2.7V to 5.25V, V = 0V, V - V = 2.048V (external reference). Internal clock mode, unless otherwise noted. AVDD DVDD GND REF+ REF- All specifications are at T = T to T , unless otherwise noted. Typical values are at T = +25C, unless otherwise noted.) A MIN MAX A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DC ACCURACY MAX1494 -19,999 +19,999 Noise-Free Resolution Count MAX1492 -1999 +1999 2.000V range 1 Integral Nonlinearity (Note 1) INL Count 200mV range 1 (V - V = 0.100V) on 200mV range, AIN+ AIN- Range Change Accuracy 10:1 Ratio (V - V = 0.100V) on 2.0V range AIN+ AIN- Rollover Error (See the Definitions V - V = full scale, AIN+ AIN- 1 Count Section) V - V = full scale AIN- AIN+ Output Noise 10 V P-P Offset Error (Zero Input Reading) Offset V = 0V (Note 2) -0 0 Reading IN Gain Error (Note 3) -0.5 +0.5 %FSR Offset Drift (Zero-Reading Drift) V = 0V (Note 4) 0.1 V/C IN Gain Drift 1 ppm/C INPUT CONVERSION RATE External-Clock Frequency 4.915 MHz External-Clock Duty Cycle 40 60 % Internal clock 5 Conversion Rate Hz External clock, f = 4.915MHz 5 CLK ANALOG INPUTS (AIN+, AIN-, bypass to GND with 0.1F or greater capacitors) RANGE bit = 0, 2V -2.0 +2.0 AIN Input-Voltage Range V (Note 5) RANGE bit = 1, 200mV -0.2 +0.2 AIN Absolute Input Voltage to -2.2 +2.2 V GND 2 MAX1492/MAX1494