20-Bit No Latency ADCs

www.DataSheet4U.com LTC2435/LTC2435-1 20-Bit No Latency ∆ΣTM ADCs with Differential Input and Differential Reference DESCRIPTIO The LTC®2435/2435-1 are 2.7V to 5.5V micropower 20-bit differential ∆Σ analog to digital converters with integrated oscillator, 3ppm INL and 0.8ppm RMS noise. They use delta-sigma technology and provide single cycle settling time for multiplexed applications. Through a single pin, the LTC2435 can be configured for better than 110dB input differential mode rejection at 50Hz or 60Hz ±2%, or it can be driven by an external oscillator for a user defined rejection frequency. The LTC2435-1 can be configured for better than 87dB input differential mode rejection over the range of 49Hz to 61.2Hz (50Hz and 60Hz ±2% simultaneously). The internal oscillator requires no external frequency setting components. The converters accept any external differential reference voltage from 0.1V to VCC for flexible ratiometric and remote sensing measurement configurations. The fullscale differential input range is from – 0.5VREF to 0.5VREF. The reference common mode voltage, VREFCM, and the input common mode voltage, VINCM, may be independently set anywhere within the GND to VCC range of the LTC2435/LTC2435-1. The DC common mode input rejection is better than 120dB. The LTC2435/LTC2435-1 communicate through a flexible 3-wire digital interface which is compatible with SPI and MICROWIRETM protocols. , LTC and LT are registered trademarks of Linear Technology Corporation. No Latency ∆Σ is a trademark of Linear Technology Corporation. MICROWIRE is a trademark of National Semiconductor Corporation. Protected by U.S. Patents including 6140950, 6169506. FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 2× Speed Up Version of the LTC2430: 15Hz Output × Rate, 60Hz Notch—LTC2435; 13.75Hz Output Rate, Simultaneous 50Hz/60Hz Notch—LTC2435-1 Differential Input and Differential Reference with GND to VCC Common Mode Range 3ppm INL, No Missing Codes 10ppm Gain Error 0.8ppm Noise Single Conversion Settling Time for Multiplexed Applications Internal Oscillator—No External Components Required Single Supply 2.7V to 5.5V Operation Low Supply Current (200µA,4µA in Auto Sleep) 20-Bit ADC in Narrow SSOP-16 Package (SO-8 Footprint) APPLICATIO S ■ ■ ■ ■ ■ ■ ■ ■ ■ Direct Sensor Digitizer Weight Scales Direct Temperature Measurement Gas Analyzers Strain Gage Transducers Instrumentation Data Acquisition Industrial Process Control 6-Digit DVMs TYPICAL APPLICATIO S 2.7V TO 5.5V 2 14 INL (ppm OF VREF) 10 8 6 VCC 1µF VCC FO LTC2435/ LTC2435-1 REFERENCE VOLTAGE 0.1V TO VCC ANALOG INPUT RANGE –0.5VREF TO 0.5VREF 3 4 5 6 REF + REF IN + IN – GND – = INTERNAL OSC/50Hz REJECTION (LTC2435) = EXTERNAL CLOCK SOURCE = INTERNAL OSC/60Hz REJECTION (LTC2435) = INTERNAL 50Hz/60Hz REJECTION (LTC2435-1) SCK 13 3-WIRE SPI INTERFACE –2 –4 –6 –8 FO = GND VCC = 5V VREF = 5V VINCM = VINCM = 2.5V –1.5 SDO CS 12 11 1, 7, 8, 9, 10, 15, 16 –10 –2.5 2435 TA01 U 4 2 0 U U Integral Nonlinearity vs Input TA = 25°C TA = 85°C TA = –45°C –0.5 0.5 1.5 INPUT VOLTAGE (V) 2.5 2435 G04 24351fa 1 LTC2435/LTC2435-1 ABSOLUTE (Notes 1, 2) AXI U RATI GS PACKAGE/ORDER I FOR ATIO TOP VIEW GND VCC REF + REF – IN + IN – GND GND 1 2 3 4 5 6 7 8 16 GND 15 GND 14 FO 13 SCK 12 SDO 11 CS 10 GND 9 GND Supply Voltage (VCC) to GND .......................– 0.3V to 7V Analog Input Pins Voltage to GND .................................... – 0.3V to (VCC + 0.3V) Reference Input Pins Voltage to GND .................................... – 0.3V to (VCC + 0.3V) Digital Input Voltage to GND ........ – 0.3V to (VCC + 0.3V) Digital Output Voltage to GND ..... – 0.3V to (VCC + 0.3V) Operating Temperature Range LTC2435C/LTC2435-1C ........................... 0°C to 70°C LTC2435I/LTC2435-1I ........................ – 40°C to 85°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C ORDER PART NUMBER LTC2435CGN LTC2435IGN LTC2435-1CGN LTC2435-1IGN GN PART MARKING 2435 2435I 24351 24351I GN PACKAGE 16-LEAD PLASTIC SSOP TJMAX = 125°C, θJA = 95°C/W Consult LTC Marketing for parts specified with wider operating temperature ranges. The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Notes 3, 4) PARAMETER Integral Nonlinearity CONDITIONS ● ● ● ELECTRICAL CHARACTERISTICS MIN 20 TYP 2 3 10 2 100 MAX UNITS Bits ppm of VREF ppm of VREF ppm of VREF mV nV/°C Resolution (No Missing Codes) 0.1V ≤ VREF ≤ VCC, –0.5 • VREF ≤ VIN ≤ 0.5 • VREF, (Note 5) 5V ≤ VCC ≤ 5.5V, REF+ = 2.5V, REF– = GND, VINCM = 1.25V, (Note 6) 5V ≤ VCC ≤ 5.5V, REF+ = 5V, REF– = GND, VINCM = 2.5V, (Note 6) 2.7V ≤ VCC ≤ 5.5V, REF+ = 2.5V, REF– = GND, VINCM = 1.25V, (Note 6) 2.5V ≤ REF+ ≤ VCC, REF– = GND, GND ≤ IN+ = IN– ≤ VCC, (Note 14) 2.5V ≤ REF+ ≤ VCC, REF– = GND, GND ≤ IN+ = IN– ≤ VCC 2.5V ≤ REF+ ≤ VCC, REF– = GND, IN+ = 0.75REF+, IN– = 0.25 • REF+ 2.5V ≤ REF+ ≤ VCC, REF– = GND, IN+ = 0.75REF+, IN– = 0.25 • REF+ 2.5V ≤ REF+ ≤ VCC, REF– = GND, IN+ = 0.25 • REF+, IN– = 0.75 • REF+ 2.5V ≤ REF+ ≤ VCC, REF– = GND, IN+ = 0.25 • REF+, IN– = 0.75 • REF+ 5V ≤ VCC ≤ 5.5V, REF+ = 5V, REF – = GND, GND ≤ IN– = IN+ ≤ VCC, (Note 13) 20 5 Offset Error Offset Error Drift Positive Gain Error Positive Gain Error Drift Negative Gain Error Negative Gain Error Drift Output Noise ● 10 0.1 25 ppm of VREF ppm of VREF/°C ● 10 0.1 4 25 ppm of VREF ppm of VREF/°C µVRMS CO VERTER CHARACTERISTICS PARAMETER Input Common Mode Rejection DC CONDITIONS 2.5V GND ≤ REF+ ≤ The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Notes 3, 4) MIN ● TYP 120 MAX UNITS dB VCC, REF– = GND, ≤ IN– = IN+ ≤ VCC (Note 5) 110 24351fa 2 U W U U WW W U LTC2435/LTC2435-1 CO VERTER CHARACTERISTICS PARAMETER Input Common Mode Rejection 60Hz ±2% (LTC2435) Input Common Mode Rejection 50Hz ±2% (LTC2435) Input Normal Mode Rejection 60Hz ±2% (LTC2435) Input Normal Mode Rejection 50Hz ±2% (LTC2435) Input Common Mode Rejection 49Hz to 61.2Hz (LTC2435-1) Input Normal Mode Rejection 49Hz to 61.2Hz (LTC2435-1) Input Normal Mode Rejection External Clock fEOSC/2560 ±14% Input Normal Mode Rejection External Clock fEOSC/2560 ±4% Reference Common Mode Rejection DC Power Supply Rejection, DC Power Supply Rejection, 50Hz ±2% CONDITIONS – 2.5V CC, REF = GND, – = IN+ ≤ V , (Notes 5, 7) GND ≤ IN CC 2.5V ≤ REF+ ≤ VCC, REF– = GND, GND ≤ IN – = IN+ ≤ VCC, (Notes 5, 8) The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Notes 3, 4) MIN ● ● ● ● ● ● ● ● ● Power Supply Rejection, 60Hz ±2% REF+ = 2.5V, REF– = GND, IN– = IN+ = GND, (Note 7) REF+ = 2.5V, REF– = GND, IN– = IN+ = GND, (Note 8) A ALOG I PUT A D REFERE CE The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3) SYMBOL IN+ IN– VIN REF+ REF– VREF CS (IN+) CS CS (IN–) (REF–) (IN+) (REF+) (REF–) CS (REF+) IDC_LEAK IDC_LEAK IDC_LEAK PARAMETER Absolute/Common Mode IN+ Voltage Absolute/Common Mode IN– Voltage Input Differential Voltage Range (IN+ – IN–) Absolute/Common Mode REF+ Voltage Absolute/Common Mode REF– Voltage Reference Differential Voltage Range (REF+ – REF–) IN+ Sampling Capacitance IN– Sampling Capacitance REF+ Sampling Capacitance REF– Sampling Capacitance IN+ DC Leakage Current IN– DC Leakage Current REF+ DC Leakage Current REF– DC Leakage Current CS = VCC, IN+ = GND CS = VCC, IN– = VCC CS = VCC, REF+ = VCC CS = VCC, REF– = GND ● ● ● ● IDC_LEAK (IN–) U U U U TYP MAX UNITS dB dB ≤ REF+ ≤ V 140 140 110 110 120 87 87 110 130 120 140 100 120 120 120 120 (Notes 5, 7) (Notes 5, 8) 2.5V ≤ REF+ ≤ VCC, REF– = GND, GND ≤ IN– = IN+ ≤ VCC, (Notes 5, 7) FO = GND (Note 5) External Oscillator (Note 5) External Oscillator (Note 5) 2.5V ≤ REF+ ≤ VCC, GND ≤ REF– ≤ 2.5V, VREF = 2.5V, IN– = IN+ = GND (Note 5) REF+ = VCC, REF– = GND, IN– = IN+ = GND dB dB dB dB dB dB dB dB dB dB U CONDITIONS ● ● ● ● ● ● MIN GND – 0.3V GND – 0.3V –VREF/2 0.1 GND 0.1 TYP MAX VCC + 0.3V VCC + 0.3V VREF/2 VCC VCC – 0.1V VCC UNITS V V V V V V pF pF pF pF 1.5 1.5 1.5 1.5 –10 –10 –10 –10 1 1 1 1 10 10 10 10 nA nA nA nA 24351fa 3 LTC2435/LTC2435-1 DIGITAL I PUTS A D DIGITAL OUTPUTS SYMBOL VIH VIL VIH VIL IIN IIN CIN CIN VOH VOL VOH VOL IOZ PARAMETER High Level Input Voltage CS, FO Low Level Input Voltage CS, FO High Level Input Voltage SCK Low Level Input Voltage SCK Digital Input Current CS, FO Digital Input Current SCK Digital Input Capacitance CS, FO Digital Input Capacitance SCK High Level Output Voltage SDO Low Level Output Voltage SDO High Level Output Voltage SCK Low Level Output Voltage SCK Hi-Z Output Leakage SDO (Note 9) IO = –800µA IO = 1.6mA IO = –800µA (Note 10) IO = 1.6mA (Note 10) ● ● ● ● ● The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3) CONDITIONS 2.7V ≤ VCC ≤ 5.5V 2.7V ≤ VCC ≤ 3.3V 4.5V ≤ VCC ≤ 5.5V 2.7V ≤ VCC ≤ 5.5V 2.7V ≤ VCC ≤ 5.5V (Note 9) 2.7V ≤ VCC ≤ 3.3V (Note 9) 4.5V ≤ VCC ≤ 5.5V (Note 9) 2.7V ≤ VCC ≤ 5.5V (Note 9) 0V ≤ VIN ≤ VCC 0V ≤ VIN ≤ VCC (Note 9) ● ● ● ● ● ● POWER REQUIRE E TS SYMBOL VCC ICC PARAMETER Supply Voltage Supply Current Conversion Mode Sleep Mode Sleep Mode The ● denotes specifications which apply over the full operating temperature range, otherwise sp