LTC1594L Datasheet, PDF (4/24 Pages) Linear Technology – 4- and 8-Channel, 3V Micropower Sampling 12-Bit Serial I/O A/D Converters

LTC1594L/LTC1598L
AC CHARACTERISTICS The q denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at T_A = 25°C.(Note 5)
SYMBOL
t_SMPL
f_SMPL(MAX)
t_CONV
t_dDO
t_dis
t_en
t_hDO
t_f
t_r
t_ON
t_OFF
t_OPEN
C_IN
PARAMETER
Analog Input Sample Time
Maximum Sampling Frequency
Conversion Time
Delay Time, CLK↓ to D_OUT Data Valid
Delay Time, CS↑ to D_OUT Hi-Z
Delay Time, CLK↓ to D_OUT Enabled
Time Output Data Remains Valid After CLK↓
D_OUT Fall Time
D_OUT Rise Time
Enable Turn-On Time
Enable Turn-Off Time
Break-Before-Make Interval
Input Capacitance
CONDITIONS
See Figure 1 in Applications Information
See Figure 1 in Applications Information
See Figure 1 in Applications Information
See Test Circuits
See Test Circuits
See Test Circuits
C_LOAD = 100pF
See Test Circuits
See Test Circuits
See Figure 1 in Applications Information
See Figure 2 in Applications Information
Analog Inputs On-Channel
Off-Channel
Digital Input
MIN
1.5
q 10.5
q
q
q
q
q
q
q
q 125
TYP MAX
UNITS
CLK Cycles
kHz
12
CLK Cycles
600 1500
ns
220 600
ns
180 500
ns
520
ns
60 180
ns
80 180
ns
540 1200
ns
190 500
ns
350
ns
20
pF
5
pF
5
pF
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: All voltage values are with respect to GND.
Note 3: These devices are specified at 3V. Consult factory for 5V
specified devices (LTC1594/LTC1598).
Note 4: Increased leakage currents at elevated temperatures cause the S/H
to droop, therefore it is recommended that f_CLK ≥ 200kHz at 85°C,
f_CLK ≥ 75kHz at 70°C and f_CLK ≥ 1kHz at 25°C.
Note 5: V_CC = 2.7V, V_REF = 2.5V and CLK = 200kHz unless otherwise
specified. CSADC and CSMUX pins are tied together during the test.
Note 6: Linearity error is specified between the actual end points of the
A/D transfer curve.
Note 7: Two on-chip diodes are tied to each reference and analog input
which will conduct for reference or analog input voltages one diode drop
below GND or one diode drop above V_CC. This spec allows 50mV forward
bias of either diode for 2.7V ≤ V_CC ≤ 3.6V. This means that as long as the
reference or analog input does not exceed the supply voltage by more than
50mV, the output code will be correct. To achieve an absolute 0V to 3V
input voltage range, it will therefore require a minimum supply voltage of
2.950V over initial tolerance, temperature variations and loading.
Note 8: Recommended operating condition.
Note 9: Channel leakage current is measured after the channel selection.
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Sample Rate
1000
T_A = 25°C
V_CC = 2.7V
V_REF = 2.5V
f_CLK = 200kHz
100
10
1
0.1
1
10
100
SAMPLE FREQUENCY (kHz)
1594L/98L G01
Supply Current vs Temperature
260
T_A = 25°C
V_CC = 2.7V
220 ^VREF ^{= 2.5V}
f_CLK = 200kHz
f_SMPL = 10.5kHz
180
140
100
60
– 55 – 35 –15 5 25 45 65 85 105 125
TEMPERATURE (°C)
1594L/98L G02
4
Reference Current vs Temperature
53
52
V_CC = 2.7V
V_REF = 2.5V
51
f_CLK = 200kHz
f_SMPL = 10.5kHz
50
49
48
47
46
45
44
43
–55 –35 –15 5 25 45 65 85 105 125
TEMPERATURE (°C)
1594L/98L G03