MAX1304ECM Maxim Integrated, MAX1304ECM Datasheet - Page 28

• Manufacturer Part Number: MAX1304ECM
• Description: Analog to Digital Converters - ADC
• Manufacturer: Maxim Integrated

Specifications of MAX1304ECM

• Number Of Channels: 8
• Architecture: SAR
• Conversion Rate: 1075 KSPs
• Resolution: 12 bit
• Input Type: Single-Ended
• Snr: 71 dB
• Interface Type: Parallel
• Operating Supply Voltage: 2.7 V to 5.25 V, 4.75 V to 5.25 V
• Maximum Operating Temperature: + 85 C
• Package / Case: LQFP-48
• Maximum Power Dissipation: 1818.2 mW
• Minimum Operating Temperature: - 40 C
• Number Of Converters: 1
• Voltage Reference: 2.5 V

Table 6. ±5V Bipolar Code Table
8-/4-/2-Channel, 12-Bit, Simultaneous-Sampling ADCs
with ±10V, ±5V, and 0 to +5V Analog Input Ranges
Table 6 and Figure 13 show the two’s complement trans-
fer function for the ±5V input range MAX1308/MAX1309/
MAX1310. The FSR is four times the voltage at REF. The
internal +2.5V reference gives a +10V FSR, while an
external +2V to +3V reference allows an FSR of +8V to
+12V respectively. Calculate the LSB size using:
which equals 2.44mV when using a 2.5V reference.
28
DIGITAL OUTPUT
0111 1111 1111 =
0111 1111 1110 =
0000 0000 0001 =
0000 0000 0000 =
1111 1111 1111 =
1000 0000 0001 =
1000 0000 0000 =
COMPLEMENT
______________________________________________________________________________________
TWO’s
CODE
0x7FF
0x7FE
0x001
0x000
0xFFF
0x801
0x800
1
LSB
DIGITAL OUTPUT
EQUIVALENT
DECIMAL
(CODE
=
CODE
+2047
+2046
-2047
-2048
+1
4
-1
0
x V
10
2
12
)
REF
Bipolar ±5V Devices
(
INPUT VOLTAGE
+4.9988 ±0.5 LSB
+4.9963 ±0.5 LSB
+0.0037 ±0.5 LSB
+0.0012 ±0.5 LSB
-0.0012 ±0.5 LSB
-4.9963 ±0.5 LSB
-4.9988 ±0.5 LSB
V
REF
V
MSV
(V)
= +2.5V
= 0V
)
The input range is centered about V
MSV = AGND, and the input is symmetrical about zero.
For a custom midscale voltage, drive MSV with an
external voltage source. Noise present on MSV directly
couples into the ADC result. Use a precision, low-drift
voltage reference with adequate bypassing to prevent
MSV from degrading ADC performance. For maximum
FSR, do not violate the absolute maximum voltage rat-
ings of the analog inputs when choosing MSV.
Determine the input voltage as a function of V
V
Figure 13. ±5V Bipolar Transfer Function
MSV
, and the output code in decimal using:
0x7FD
0x7FC
0x7FF
0x7FE
0x001
0x000
0xFFF
0x803
0x802
0x801
0x800
-2048 -2046
V
CH_
= LSB x CODE
INPUT VOLTAGE (V
-1 0 +1
4 x V
(MSV)
CH_
REF
10
- V
+ V
MSV
1 LSB =
IN LSBs)
MSV
MSV
+2045
. Normally,
4 x V
2
12
+2047
REF
REF
,