Datasheet LTC1285, LTC1288 (Analog Devices) - 4

LTC1285/LTC1288
AC CHARACTERISTICS (Note 5) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
tSMPL Analog Input Sample Time See Operating Sequence 1.5 CLK Cycles fSMPL(MAX) Maximum Sampling Frequency LTC1285 ● 7.5 kHz LTC1288 ● 6.6 kHz tCONV Conversion Time See Operating Sequence 12 CLK Cycles tdDO Delay Time, CLK↓ to DOUT Data Valid See Test Circuits ● 600 1500 ns tdis Delay Time, CS↑ to DOUT Hi-Z See Test Circuits ● 220 660 ns ten Delay Time, CLK↓ to DOUT Enable See Test Circuits ● 180 500 ns thDO Time Output Data Remains Valid After CLK↓ CLOAD = 100pF 520 ns tf DOUT Fall Time See Test Circuits ● 60 180 ns tr DOUT Rise Time See Test Circuits ● 80 180 ns CIN Input Capacitance Analog Inputs, On Channel 20 pF Analog Inputs, Off Channel 5 pF Digital Input 5 pF The ● denotes specifications which apply over the full operating
Note 7:
Two on-chip diodes are tied to each reference and analog input temperature range. which will conduct for reference or analog input voltages one diode drop
Note 1:
Absolute maximum ratings are those values beyond which the life below GND or one diode drop above VCC. This spec allows 50mV forward of a device may be impaired. bias of either diode for 2.7V ≤ VCC ≤ 6V. This means that as long as the
Note 2:
All voltage values are with respect to GND. reference or analog input does not exceed the supply voltage by more than
Note 3:
These devices are specified at 3V. For 5V specified devices, see 50mV the output code will be correct. To achieve an absolute 0V to 2.7V LTC1286 and LTC1298. input voltage range will therefore require a minimum supply voltage of 2.650V over initial tolerance, temperature variations and loading. For 2.7V
Note 4:
Increased leakage currents at elevated temperatures cause the < VCC ≤ 6V, reference and analog input range cannot exceed 6.05V. If sample-and-hold to droop, therefore it is recommended that fCLK ≥ 75kHz reference and analog input range are greater than 6.05V, the output code at 70° and fCLK ≥ 1kHz at 25°C. will not be guaranteed to be correct.
Note 5:
VCC = 2.7V, VREF = 2.5V and CLK = 120kHz unless otherwise
Note 8:
The supply voltage range for the LTC1285 and the LTC1288 is specified. from 2.7V to 6V.
Note 6:
Linearity error is specified between the actual end points of the
Note 9:
Recommended operating conditions A/D transfer curve.
Note 10:
Channel leakage current is measured after the channel selection.
W U TYPICAL PERFORMANCE CHARACTERISTICS Shutdown Supply Current vs Clock Supply Current vs Sample Rate Supply Current vs Temperature Rate with CS High and CS Low
1000 250 9 TA = 25°C LTC1288 TA = 25°C VCC = 2.7V f 8 SMPL = 6.6kHz VCC = 2.7V VREF = 2.5V V 200 7 REF = 2.5V fCLK = 120kHz LTC1285 µA) LTC1288 µA) f µA) 100 6 SMPL = 7.5kHz 150 5 4 CS = 0 100 3 LTC1285 (AFTER CONVERSION) 10 2 SUPPLY CURRENT ( SUPPLY CURRENT ( SUPPLY CURRENT ( 50 VCC = 2.7V 1 VREF = 2.5V 0.002 CS = VCC fCLK = 120kHz 1 0 0 0.1 1 10 –55 –35 –15 5 25 45 65 85 105 125 1 20 40 60 80 100 120 SAMPLE RATE (kHz) TEMPERATURE (°C) FREQUENCY (kHz) LTC1285/88 • TPC01 LTC1285/88 • TPC02 LTC1285/88 • TPC03 4