MAX148BCAP+ Maxim Integrated Products, MAX148BCAP+ Datasheet - Page 19

• Manufacturer Part Number: MAX148BCAP+
• Description: IC ADC SRL 8CH 10BIT LP 20-SSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX148BCAP+

• Number Of Bits: 10
• Sampling Rate (per Second): 133k
• Data Interface: MICROWIRE™, QSPI™, Serial, SPI™
• Number Of Converters: 1
• Power Dissipation (max): 640mW
• Voltage Supply Source: Single Supply
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP
• Number Of Adc Inputs: 8
• Architecture: SAR
• Conversion Rate: 133 KSPs
• Resolution: 10 bit
• Input Type: Voltage
• Interface Type: 4-Wire (SPI, QSPI, MICROWIRE, TMS320)
• Voltage Reference: Internal 2.5 V or External
• Supply Voltage (max): 5 V
• Maximum Power Dissipation: 640 mW
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table 7. Full Scale and Zero Scale
deliver up to 350FA DC load current and have 10I or
less output impedance. If the reference has a higher out-
put impedance or is noisy, bypass it close to the VREF
pin with a 4.7FF capacitor.
Using the REFADJ input makes buffering the external
reference unnecessary. To use the direct VREF input,
disable the internal buffer by tying REFADJ to V
In power-down, the input bias current to REFADJ is
typically 25FA (MAX149) with REFADJ tied to V
REFADJ to AGND to minimize the input bias current in
power-down.
Figure 18. Bipolar Transfer Function, Full Scale (FS) = VREF/2
+ COM, Zero Scale (ZS) = COM
*COM ≥ VREF/2
011 . . . 111
011 . . . 110
000 . . . 010
000 . . . 001
000 . . . 000
111 . . . 111
111 . . . 110
111 . . . 101
100 . . . 001
100 . . . 000
VREF + COM
Full Scale
OUTPUT CODE
-FS =
1LSB =
- FS
UNIPOLAR MODE
FS =
ZS = COM
______________________________________________________________________________________
-VREF
+2.7V to +5.25V, Low-Power, 8-Channel,
VREF
2
2
VREF
1024
+ COM
+ COM
INPUT VOLTAGE (LSB)
Zero Scale
COM*
COM
+FS - 1LSB
DD
. Pull
Positive Full Scale
DD
VREF/2 + COM
.
Figure 19. Power-Supply Grounding Connection
Table 7 shows the full-scale voltage ranges for unipolar
and bipolar modes.
The external reference must have a temperature coef-
ficient of 20ppm/NC or less to achieve accuracy to within
1 LSB over the 0NC to +70NC commercial temperature
range.
Figure 17 depicts the nominal, unipolar input/output
(I/O) transfer function, and Figure 18 shows the bipolar
input/output transfer function. Code transitions occur
halfway between successive-integer LSB values. Output
coding is binary, with 1 LSB = 2.44mV (2.500V/1024)
for unipolar operation, and 1 LSB = 2.44mV [(2.500V/2 -
-2.500V/2)/1024] for bipolar operation.
R* = 10Ω
*OPTIONAL
V
+3V
DD
Serial 10-Bit ADCs
BIPOLAR MODE
Zero Scale
COM
AGND
MAX148
MAX149
SUPPLIES
COM
Transfer Function
DGND
Negative Full Scale
-VREF/2 + COM
+3V
+3V
CIRCUITRY
DIGITAL
DGND
GND
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