MAX1245 Datasheet, PDF (10/20 Pages) Maxim Integrated Products – +2.375V, Low-Power, 8-Channel, Serial 12-Bit ADC

+2.375V, Low-Power, 8-Channel,
Serial 12-Bit ADC
Table 1. Control-Byte Format
BIT 7
(MSB)
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
(LSB)
START
SEL2
SEL1
SEL0
UNI/BIP
SGL/DIF
PD1
PD0
BIT
7(MSB)
NAME
START
DESCRIPTION
The first logic “1” bit after CS goes low defines the beginning of the control byte.
6
SEL2
These three bits select which of the eight channels are used for the conversion (Tables 2 and 3).
5
SEL1
4
SEL0
3
UNI/BIP
1 = unipolar, 0 = bipolar. Selects unipolar or bipolar conversion mode. In unipolar mode, an
analog input signal from 0V to VREF can be converted; in bipolar mode, the signal can range
from -VREF/2 to +VREF/2.
2
SGL/DIF
1 = single ended, 0 = differential. Selects single-ended or differential conversions. In single-
ended mode, input signal voltages are referred to COM. In differential mode, the voltage
difference between two channels is measured (Tables 2 and 3).
1
PD1
0(LSB)
PD0
Selects clock and power-down modes.
PD1
PD0
Mode
0
0
Power-down (IQ = 1.2µA)
0
1
Unassigned
1
0
Internal clock mode
1
1
External clock mode
Table 2. Channel Selection in Single-Ended Mode (SGL/DIF = 1)
SEL2
0
1
0
1
0
1
SEL1
0
0
0
0
1
1
SEL0
0
0
1
1
0
0
CH0
+
CH1
+
CH2
+
CH3
CH4
+
+
CH5
+
CH6
CH7
COM
–
–
–
–
–
–
0
1
1
1
1
1
+
–
+
–
Table 3. Channel Selection in Differential Mode (SGL/DIF = 0)
SEL2
0
0
0
0
1
1
1
1
SEL1
0
0
1
1
0
0
1
1
SEL0
0
1
0
1
0
1
0
1
CH0
+
–
CH1
–
+
CH2
+
–
CH3
–
+
CH4
+
–
CH5
–
+
CH6
CH7
+
–
–
+
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