User guide

MAX1272/MAX1273
Fault-Protected, 12-Bit ADCs
with Software-Selectable Input Range
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(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.)
PARAMETERS SYMBOL CONDITIONS MIN TYP MAX UNITS
Converting 400 850
Standby power-down
mode
510
Input Current V
REF
= 4.096V
Full power-down mode 1
µA
POWER REQUIREMENTS
Supply Voltage V
DD
4.75 5 5.25 V
Bipolar 2.4 4
Converting
Unipolar 2.2 3
mA
Standby power-down mode 400 700
Supply Current
(Internal Reference Mode)
I
DD
Full power-down mode 1
µA
Bipolar 1.5 2.5
Converting
Unipolar 1.2 2.0
mA
Standby power-down mode 200 450
Supply Current
(External Reference Mode)
I
DD
Full power-down mode 1
µA
External reference = 4.096V ±0.3 ±1.0
Power-Supply Rejection
Ratio (Note 3)
PSRR
Internal reference ±0.5
LSB
TIMING
Clock Frequency Range f
SCLK
0.1 1.4 MHz
T/H Acquisition Time t
ACQ
(Note 4) 2.85 µs
Conversion Time t
CONV
(Note 4) 8.57 µs
Throughput Rate 87.5 ksps
Internal Reference Settling Time REF bypass capacitor initially discharged 2 ms
Device Power-Up Time External reference mode 10 µs
DIGITAL INPUTS (DIN, SCLK, and CS)
Input High-Threshold Voltage V
IH
2.4 V
Input Low-Threshold Voltage V
IL
0.8 V
Input Hysteresis V
HYS
0.2 V
Input Leakage Current I
IN
V
IN
= 0 to V
DD
-10 +10 µA
Input Capacitance C
IN
15 pF
DIGITAL OUTPUT (DOUT)
I
SINK
= 10mA 0.4
Output Voltage Low V
OL
I
SINK
= 16mA 0.6
V
Output Voltage High V
OH
I
SOURCE
= 0.5mA
V
DD
- 0.5
V
Three-State Leakage Current I
L
CS = V
DD
-10 +10 µA
Three-State Output Capacitance C
OUT
CS = V
DD
15 pF