Datasheet LTC1274, LTC1277 (Analog Devices) - 7

LTC1274/LTC1277
W U TYPICAL PERFORMANCE CHARACTERISTICS Power Supply Feedthrough vs Reference Voltage vs Supply Current vs Temperature Ripple Frequency Load Current
3.0 0 2.435 f f SAMPLE = 100kHz –10 SAMPLE = 100kHz 2.5 2.430 –20 –30 2.0 2.425 –40 DGND (V 1.5 –50 RIPPLE = 0.1V) 2.420 –60 VSS (VRIPPLE = 10mV) 1.0 2.415 –70 SUPPLY CURRENT (mA) REFERENCE VOLTAGE (V) –80 0.5 2.410 AV –90 DD (VRIPPLE = 1mV) 0 –100 2.405 –55 –25 0 25 50 75 100 125 AMPLITUDE OF POWER SUPPLY FEEDTHROUGH (dB) 1 10 100 1000 – 6 – 5 – 4 – 3 – 2 – 1 0 1 TEMPERATURE (°C) RIPPLE FREQUENCY (kHz) LOAD CURRENT (mA) LTC1274/77 • TPC12 LT1274/77 • TPC11 LT1274/77 • TPC13
Supply Current vs Supply Current vs Sample Rate Wake-Up Time vs Supply Voltage With Sleep and Nap Modes CREF (Sleep Mode)
3.0 10000 10 f C SAMPLE = 100kHz REF = 4.7µF 9 TA = 25°C 2.5 WITHOUT SLEEP OR NAP 8 1000 µA) 2.0 NAP MODE 7 6 1.5 100 5 NAP = REFRDY 4 1.0 (SLEEP MODE) WAKE-UP TIME (ms) 3 SUPPLY CURRENT (mA) SUPPLY CURRENT ( 10 NAP = 5V 2 0.5 (SLEEP MODE) 1 0 1 0 0 1 2 3 4 5 6 0.1 1 10 100 1k 10k 100k 0 5 10 15 20 25 30 35 40 45 50 SUPPLY VOLTAGE (V) C SAMPLE RATE (Hz) REF (µF) LTC1274/77 • TPC14 LTC1274/77 • TPC15 LTC1274/77 • TPC16
U U U PI FU CTIO S LTC1274 D3 to D0 (Pins 13 to 16):
Three-State Data Outputs.
AIN (Pin 1):
Analog Input. 0V to 4.096V, unipolar (VSS =
REFRDY (Pin 17):
Reference Ready Signal. It goes high 0V) or ±2.048V, bipolar (VSS = – 5V). when the reference has settled after SLEEP indicating that the ADC is ready to sample.
VREF (Pin 2):
2.42V Reference Output. Bypass to AGND (10µF tantalum in parallel with 0.1µF ceramic). VREF can be
SLEEP (Pin 18):
SLEEP Mode Input. Tie this pin to low to overdriven positive with an external reference voltage. put the ADC in Sleep mode and save power (REFRDY will go low). The device will draw 1µA in this mode.
AGND (Pin 3):
Analog Ground.
CONVST (Pin 19):
Conversion Start Signal. This active low
D11 to D4 (Pins 4 to 11):
Three-State Data Outputs. D11 signal starts a conversion on its falling edge (to recognize is the Most Significant Bit. CONVST, CS has to be low.)
DGND (Pin 12):
Digital Ground. 7