MAX1332 Datasheet, PDF (18/25 Pages) Maxim Integrated Products – 3Msps/2Msps, 5V/3V, 2-Channel, True-Differential 12-Bit ADCs

3Msps/2Msps, 5V/3V, 2-Channel, True-
Differential 12-Bit ADCs
Table 1. Unipolar Code Table (MAX1332)
BINARY DIGITAL OUTPUT
CODE D11–D0
1111 1111 1111
1111 1111 1110
1000 0000 0001
1000 0000 0000
0111 1111 1111
0000 0000 0001
0000 0000 0000
HEXADECIMAL EQUIVALENT
OF D11–D0
0xFFF
0xFFE
0x801
0x800
0x7FF
0x001
0x000
DECIMAL EQUIVALENT OF
D11–D0 (CODE₁₀)
4095
4094
2049
2048
2047
1
0
DIFFERENTIAL INPUT
VOLTAGE (V) (V_REF = 4.096V )
+4.095 ±0.5 LSB
+4.094 ±0.5 LSB
+2.049 ±0.5 LSB
+2.048 ±0.5 LSB
+2.047 ±0.5 LSB
+0.001 ±0.5 LSB
+0.000 ±0.5 LSB
Table 2. Bipolar Code Table (MAX1332)
TWO’s-COMPLEMENT
DIGITAL OUTPUT CODE
D11–D0
0111 1111 1111
0111 1111 1110
0000 0000 0001
0000 0000 0000
1111 1111 1111
1000 0000 0001
1000 0000 0000
HEXADECIMAL EQUIVALENT
OF D11–D0
0x7FF
0x7FE
0x001
0x000
0xFFF
0x801
0x800
DECIMAL EQUIVALENT OF
D11–D0 (CODE₁₀)
+2047
+2046
+1
0
-1
-2047
-2048
DIFFERENTIAL INPUT
VOLTAGE (V) (V_REF = 4.096V)
+2.047 ±0.5 LSB
+2.046 ±0.5 LSB
+0.001 ±0.5 LSB
0.000 ±0.5 LSB
-0.001 ±0.5 LSB
-2.047 ±0.5 LSB
-2.048 ±0.5 LSB
Determine the differential analog input voltage as a
function of V_REF and the digital output code with the fol-
lowing equation:
where:
∆V_AIN = LSB × CODE₁₀ ± 0.5 × LSB
∆V_AIN = V_{AIN_P} − V_{AIN_N}
LSB = ^VREF = ^VREF
212 4096
CODE₁₀ = the decimal equivalent of the digital output
code (see Tables 1 and 2).
±0.5 x LSB represents the quantization error that is
inherent to any ADC.
When using a 4.096V reference, 1 LSB equals 1.0mV.
When using a 2.5V reference, 1 LSB equals 0.61mV.
Applications Information
External Reference
The MAX1332/MAX1333 use an external reference
between 1V and (AV_DD + 50mV). Bypass REF with
a 1µF capacitor in parallel with a 0.1µF capacitor
to AGND for best performance (see the Typical
Operating Circuit).
Connection to Standard Interfaces
The MAX1332/MAX1333 serial interface is fully compat-
ible with SPI, QSPI and MICROWIRE (see Figure 11). If
a serial interface is available, set the µC’s serial inter-
face in master mode so the µC generates the serial
clock. Choose a clock frequency based on the AV_DD
and DV_DD amplitudes.
SPI and MICROWIRE
When using SPI or MICROWIRE, the MAX1332/
MAX1333 are compatible with all four modes pro-
grammed with the CPHA and CPOL bits in the SPI or
MICROWIRE control register. (This control register is in
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