MAX1245_09 Datasheet, PDF (10/21 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)
START
BIT
7(MSB)
6
5
4
3
2
1
0(LSB)
BIT 6
SEL2
NAME
START
SEL2
SEL1
SEL0
UNI/BIP
SGL/DIF
PD1
PD0
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
(LSB)
SEL1
SEL0
UNI/BIP
SGL/DIF
PD1
PD0
DESCRIPTION
The first logic “1” bit after CS goes low defines the beginning of the control byte.
These three bits select which of the eight channels are used for the conversion (Tables 2 and 3).
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.
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).
Selects clock and power-down modes.
PD1
PD0
Mode
0
0
Power-down (I_Q = 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
0
1
SEL1
0
0
0
0
1
1
1
1
SEL0
0
0
1
1
0
0
1
1
CH0
+
CH1
+
CH2
+
CH3
CH4
+
+
CH5
+
CH6
+
CH7
+
COM
–
–
–
–
–
–
–
–
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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