LTC2430/LTC2431 TM 20-Bit No Latency DS ADCs with Differential Input and Differential Reference FEATURES DESCRIPTIO n Low Supply Current (200m A in Conversion Mode The LTC 2430/LTC2431 are 2.7V to 5.5V micropower and 4m A in Autosleep Mode) 20-bit differential analog-to-digital converters with an n Differential Input and Differential Reference integrated oscillator, 3ppm INL and 0.56ppm RMS noise. with GND to V Common Mode Range They use delta-sigma technology and provide single cycle CC n 3ppm INL, No Missing Codes settling time for multiplexed applications. Through a n 10ppm Full-Scale Error and 1ppm Offset single pin, the LTC2430/LTC2431 can be configured for n 0.56ppm Noise, 20.8 ENOBs better than 110dB differential mode rejection at 50Hz or n No Latency: Digital Filter Settles in a Single Cycle. 60Hz 2%, or they can be driven by an external oscillator Each Conversion Is Accurate, Even After an for a user-defined rejection frequency. The internal oscil- Input Step lator requires no external frequency setting components. n Single Supply 2.7V to 5.5V Operation The converters accept any external differential reference n Internal OscillatorNo External Components voltage from 0.1V to V for flexible ratiometric and CC Required remote sensing measurement configurations. The full- n 110dB Min, 50Hz/60Hz Notch Filter scale differential input range is from 0.5V to 0.5V . REF REF n Pin Compatible with 24-Bit LTC2410/LTC2411 The reference common mode voltage, V , and the REFCM U input common mode voltage, V , may be indepen- INCM APPLICATIO S dently set anywhere within GND to V . The DC common CC n mode input rejection is better than 120dB. Direct Sensor Digitizer n Weight Scales The LTC2430/LTC2431 communicate through a flexible n Direct Temperature Measurement 3-wire digital interface that is compatible with SPI and n Gas Analyzers TM MICROWIRE protocols. n Strain Gauge Transducers , LTC and LT are registered trademarks of Linear Technology Corporation. n Instrumentation No Latency DS is a trademark of Linear Technology Corporation. MICROWIRE is a trademark of National Semiconductor Corporation. n Data Acquisition n Industrial Process Control n DVMs and Meters TYPICAL APPLICATIO S Total Unadjusted Error (V = 5V, V = 5V) CC REF (V + 0.25V) TO 20V OUT 5 V64 V = 5V OUT CC LT1790 3V TO 5V 4 V = 5V REF V = V = 2.5V INCM INCM 3 0.1F 12 F = GND O 4.7F 2 V 25C 85C CC = INTERNAL OSC/50Hz REJECTION 1 = EXTERNAL CLOCK SOURCE V F CC O 0 0.1F = INTERNAL OSC/60Hz REJECTION LTC2431 + 1 REF 45C SCK 2 REF 3-WIRE 3 SPI INTERFACE ANALOG INPUT RANGE + IN SDO 4 0.5V TO 0.5V REF REF IN CS 5 2.5 2 1.5 1 0.5 0 0.5 1 1.5 2 2.5 GND 24301 TA01 INPUT VOLTAGE (V) 24301 G01 24301f 1 TUE (ppm OF V ) REF U DS ULTC2430/LTC2431 ABSOLUTE AXI U RATI GS (Notes 1, 2) Supply Voltage (V ) to GND.......................0.3V to 7V Digital Output Voltage to GND ..... 0.3V to (V + 0.3V) CC CC Analog Input Pins Voltage Operating Temperature Range to GND ......................................... 0.3V to (V + 0.3V) LTC2430C/LTC2431C .............................. 0 C to 70 C CC Reference Input Pins Voltage LTC2430I/LTC2431I ........................... 40 C to 85 C to GND ......................................... 0.3V to (V + 0.3V) Storage Temperature Range ................. 65 C to 150 C CC Digital Input Voltage to GND ........ 0.3V to (V + 0.3V) Lead Temperature (Soldering, 10 sec).................. 300 C CC UUW PACKAGE/ORDER I FOR ATIO TOP VIEW ORDER PART NUMBER ORDER PART NUMBER GND 1 16 GND LTC2430CGN LTC2431CMS V 2 15 GND CC TOP VIEW + LTC2430IGN LTC2431IMS REF 3 14 F O V 1 10 F CC O + REF 2 9 SCK REF 4 13 SCK REF 3 8 SDO + + IN 5 12 SDO IN 4 7 CS IN 5 6 GND IN 6 11 CS MS PART MARKING GN PART MARKING MS PACKAGE GND 7 10 GND 10-LEAD PLASTIC MSOP GND 8 9 GND 2430 LTXD T = 125 C, q = 120 C/W JMAX JA LTXE 2430I GN PACKAGE 16-LEAD PLASTIC SSOP T = 125 C, q = 110 C/W JMAX JA Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL 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 , 0.5 V V 0.5 V (Note 5) l 20 Bits REF CC REF IN REF + Integral Nonlinearity 4.5V V 5.5V, REF = 2.5V, REF = GND, V = 1.25V (Note 6) 2 ppm of V CC INCM REF + 5V V 5.5V, REF = 5V, REF = GND, V = 2.5V (Note 6) l 3 20 ppm of V CC INCM REF + REF = 2.5V, REF = GND, V = 1.25V (Note 6) 10 ppm of V INCM REF + Offset Error 2.5V REF V , REF = GND, l 520 m V CC + GND IN = IN V (Note 14) CC + Offset Error Drift 2.5V REF V , REF = GND, 50 nV/ C CC + GND IN = IN V CC + Positive Full-Scale Error 2.5V REF V , REF = GND, l 10 20 ppm of V CC REF + + + IN = 0.75REF , IN = 0.25 REF + Positive Full-Scale Error Drift 2.5V REF V , REF = GND, 0.1 ppm of V / C CC REF + + + IN = 0.75REF , IN = 0.25 REF + Negative Full-Scale Error 2.5V REF V , REF = GND, l 10 20 ppm of V CC REF + + + IN = 0.25 REF , IN = 0.75 REF + Negative Full-Scale Error Drift 2.5V REF V , REF = GND, 0.1 ppm of V / C CC REF + + + IN = 0.25 REF , IN = 0.75 REF + Total Unadjusted Error 4.5V V 5.5V, REF = 2.5V, REF = GND, V = 1.25V 3 ppm of V CC INCM REF + 5V V 5.5V, REF = 5V, REF = GND, V = 2.5V 6 ppm of V CC INCM REF + REF = 2.5V, REF = GND, V = 1.25V 15 ppm of V INCM REF + Output Noise 5V V 5.5V, REF = 5V, V = GND, 2.8 m V CC REF RMS + GND IN = IN 5V, (Note 13) 24301f 2 U WWW