LTC2420 20-Bit m Power TM No Latency DS ADC in SO-8 FEATURES DESCRIPTIO n 20-Bit ADC in SO-8 Package The LTC 2420 is a micropower 20-bit A/D converter with n 8ppm INL, No Missing Codes at 20 Bits an integrated oscillator, 8ppm INL and 1.2ppm RMS n 4ppm Full-Scale Error noise that operates from 2.7V to 5.5V. It uses delta-sigma n 0.5ppm Offset technology and provides a digital filter that settles in a n 1.2ppm Noise single cycle for multiplexed applications. Through a single n Digital Filter Settles in a Single Cycle. Each pin, the LTC2420 can be configured for better than 110dB Conversion Is Accurate, Even After an Input Step rejection at 50Hz or 60Hz 2%, or it can be driven by an n Fast Mode: 16-Bit Noise, 12 Bits TUE at 100sps external oscillator for a user-defined rejection frequency n Internal OscillatorNo External Components in the range 1Hz to 800Hz. The internal oscillator requires Required no external frequency setting components. n 110dB Min, 50Hz/60Hz Notch Filter The converter accepts any external reference voltage from n Reference Input Voltage: 0.1V to V CC 0.1V to V . With its extended input conversion range of CC n Live ZeroExtended Input Range Accommodates 12.5% V to 112.5% V , the LTC2420 smoothly REF REF 12.5% Overrange and Underrange resolves the offset and overrange problems of preceding n Single Supply 2.7V to 5.5V Operation sensors or signal conditioning circuits. n Low Supply Current (200m A) and Auto Shutdown n The LTC2420 communicates through a flexible 3-wire Pin Compatible with 24-Bit LTC2400 digital interface which is compatible with SPI and U TM APPLICATIO S MICROWIRE protocols. , LTC and LT are registered trademarks of Linear Technology Corporation. n Weight Scales No Latency is a trademark of Linear Technology Corporation. MICROWIRE is a trademark of National Semiconductor Corporation. n Direct Temperature Measurement n Gas Analyzers n Strain Gauge Transducers n Instrumentation n Data Acquisition n Industrial Process Control n 4-Digit DVMs Total Unadjusted Error (3V Supply) TYPICAL APPLICATIO 10 V = 3V CC 8 V = 2.5V REF 2.7V TO 5.5V 6 V CC 1F = INTERNAL OSC/50Hz REJECTION 4 1 8 = EXTERNAL CLOCK SOURCE V F CC O = INTERNAL OSC/60Hz REJECTION 2 LTC2420 0 REFERENCE 2 7 2 VOLTAGE V SCK REF 0.1V TO V 4 CC T = 55C, 45C, 25C, 90C 3-WIRE A 6 ANALOG 3 6 SPI INTERFACE V SDO INPUT RANGE IN 8 0.12V TO 1.12V REF REF 4 5 GND CS 10 0 0.5 1.0 1.5 2.0 2.5 2420 TA01 INPUT VOLTAGE (V) 2420 G01 1 ERROR (ppm) U DS ULTC2420 UUW ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Notes 1, 2) ORDER PART NUMBER TOP VIEW Supply Voltage (V ) to GND.......................0.3V to 7V CC Analog Input Voltage to GND ....... 0.3V to (V + 0.3V) V 1 8 F CC CC O LTC2420CS8 Reference Input Voltage to GND .. 0.3V to (V + 0.3V) V 2 7 SCK CC REF LTC2420IS8 Digital Input Voltage to GND ........ 0.3V to (V + 0.3V) V 3 6 SDO CC IN Digital Output Voltage to GND ..... 0.3V to (V + 0.3V) GND 4 5 CS CC S8 PART MARKING Operating Temperature Range S8 PACKAGE 8-LEAD PLASTIC SO 2420 LTC2420C ............................................... 0 C to 70 C T = 125 C, q = 130 C/W JMAX JA 2420I LTC2420I............................................ 40 C to 85 C Storage Temperature Range ................. 65 C to 150 C Consult factory for Military grade parts. Lead Temperature (Soldering, 10 sec).................. 300 C CONVERTER CHARACTERISTICS The l denotes specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. (Notes 3, 4) A PARAMETER CONDITIONS MIN TYP MAX UNITS Resolution (No Missing Codes) 0.1V V V , (Note 5) l 20 Bits REF CC Integral Nonlinearity V = 2.5V (Note 6) l 4 10 ppm of V REF REF V = 5V (Note 6) l 8 20 ppm of V REF REF Integral Nonlinearity (Fast Mode) V = 5V, V = 2.5V, 100 Samples/Second, f = 2.048MHz l 40 250 ppm of V REF REF O REF Offset Error 2.5V V V l 0.5 10 ppm of V REF CC REF Offset Error (Fast Mode) 2.5V < V < 5V, 100 Samples/Second, f = 2.048MHz 3 ppm of V REF O REF Offset Error Drift 2.5V V V 0.04 ppm of V / C REF CC REF Full-Scale Error 2.5V V V l 4 10 ppm of V REF CC REF Full-Scale Error (Fast Mode) 2.5V < V < 5V, 100 Samples/Second, f = 2.048MHz 10 ppm of V REF O REF Full-Scale Error Drift 2.5V V V 0.04 ppm of V / C REF CC REF Total Unadjusted Error V = 2.5V 8 ppm of V REF REF V = 5V 16 ppm of V REF REF Output Noise V = 0V (Note 13) 6 m V IN RMS Output Noise (Fast Mode) V = 5V, 100 Samples/Second, f = 2.048MHz 20 m V REF O RMS Normal Mode Rejection 60Hz 2% (Note 7) l 110 130 dB Normal Mode Rejection 50Hz 2% (Note 8) l 110 130 dB Power Supply Rejection, DC V = 2.5V, V = 0V 100 dB REF IN Power Supply Rejection, 60Hz 2% V = 2.5V, V = 0V, (Notes 7, 15) 110 dB REF IN Power Supply Rejection, 50Hz 2% V = 2.5V, V = 0V, (Notes 8, 15) 110 dB REF IN 2 U U WWW