User guide
MAX1272/MAX1273
Fault-Protected, 12-Bit ADCs
with Software-Selectable Input Range
_______________________________________________________________________________________ 5
TIMING CHARACTERISTICS
(V
DD
= 4.75V to 5.25V, unipolar/bipolar input range, external reference mode, V
REF
= 4.096V, C
REF
= 1.0µF, f
SCLK
= 1.4MHz,
50% duty cycle, C
LOAD
= 50pF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Figures 1 and 4)
PARAMETERS SYMBOL CONDITIONS MIN TYP MAX UNITS
DIN to SCLK Setup t
DS
100 ns
DIN to SCLK Hold t
DH
0ns
SCLK Fall to Output Data Valid t
DO
20 250 ns
CS Fall to Output Enable t
DV
100 ns
CS Rise to Output Disable t
TR
100 ns
CS to SCLK Rise Setup t
CSS
100 ns
CS to SCLK Rise Hold t
CSH
0ns
SCLK Pulse Width High t
CH
200 ns
SCLK Pulse Width Low t
CL
200 ns
Note 1: Accuracy specifications tested at V
DD
= 5V. Performance at power-supply tolerance limit is guaranteed by power-supply
rejection test.
Note 2: Offset error nulled. The ideal last-code transition is (FS - 1.5 LSB).
Note 3: PSRR measured at full scale. Tested at ±10V (MAX1272) and ±4.096V (MAX1273) input ranges.
Note 4: Acquisition and conversion times are dependent on the clock speed.
Typical Operating Characteristics
(Typical operating circuit, BIP = RNG = 1, V
DD
= 5V, external reference mode, V
REF
= 4.096V, C
REF
= 1.0µF, f
SCLK
= 1.4MHz,
50% duty cycle, 87ksps, T
A
= +25°C, unless otherwise noted.)
CONVERTING SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX1272/73 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
5.205.155.05 5.104.85 4.90 4.95 5.004.80
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0
4.75 5.25
INTERNAL
REFERENCE
EXTERNAL
REFERENCE
V
AIN
= 0
CONVERTING SUPPLY CURRENT
vs. TEMPERATURE
MAX1272/73 toc02
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
6035-15 10
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0
-40 85
V
AIN
= 0
INTERNAL
REFERENCE
EXTERNAL
REFERENCE
STANDBY SUPPLY CURRENT
vs. TEMPERATURE
MAX1272/73 toc03
TEMPERATURE (
°
C)
STANDBY SUPPLY CURRENT (mA)
603510-15
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
-40 85
V
AIN
= 0
INTERNAL
REFERENCE
EXTERNAL
REFERENCE