MAX1304ECM/V+ Maxim Integrated Products, MAX1304ECM/V+ Datasheet - Page 28

• Manufacturer Part Number: MAX1304ECM/V+
• Description: IC ADC 12BIT 4000KSPS 8CH 48LQFP
• Manufacturer: Maxim Integrated Products

Specifications of MAX1304ECM/V+

• Number Of Bits: 12
• Sampling Rate (per Second): 3.65M
• Data Interface: Parallel
• Number Of Converters: 1
• Power Dissipation (max): 1.82W
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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
2
10
12
)
REF
Bipolar ±5V Devices
+4.9988 ± 0.5 LSB
+4.9963 ± 0.5 LSB
+0.0037 ± 0.5 LSB
+0.0012 ± 0.5 LSB
(
INPUT VOLTAGE
-0.0012 ± 0.5 LSB
-4.9963 ± 0.5 LSB
-4.9988 ± 0.5 LSB
V
REF
V
MSV
(V)
= +2.5V
= 0
)
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
,