MAX1270BCAI+ Maxim Integrated Products, MAX1270BCAI+ Datasheet - Page 17

• Manufacturer Part Number: MAX1270BCAI+
• Description: IC ADC 12-BIT MULTIRANGE 28-SSOP
• Manufacturer: Maxim Integrated Products
• Type: Data Acquisition System (DAS), ADCr

Specifications of MAX1270BCAI+

• Resolution (bits): 12 b
• Sampling Rate (per Second): 110k
• Data Interface: Serial
• Voltage Supply Source: Single Supply
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 28-SSOP
• Number Of Adc Inputs: 8
• Architecture: SAR
• Conversion Rate: 110 KSPs
• Resolution: 12 bit
• Interface Type: 3-Wire (SPI, QSPI, MICROWIRE)
• Voltage Reference: Internal 4.096 V or External
• Supply Voltage (max): 5 V
• Maximum Power Dissipation: 762 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ry in unipolar mode with 1 LSB = (FS / 4096) and two’s
complement binary in bipolar mode with 1 LSB = [(2 x
Output data coding for the MAX1270/MAX1271 is bina-
| FS | ) / 4096]. Code transitions occur halfway between
successive-integer LSB values. Figures 14a and 14b
show the input/output (I/O) transfer functions for unipo-
lar and bipolar operations, respectively. For full-scale
values, refer to Table 3.
Careful PC board layout is essential for best system
performance. Use a ground plane for best perfor-
mance. To reduce crosstalk and noise injection, keep
analog and digital signals separate. Connect analog
grounds and DGND in a star configuration to AGND.
For noise-free operation, ensure the ground return from
AGND to the supply ground is low impedance and as
short as possible. Connect the logic grounds directly to
the supply ground. Bypass V
capacitors to AGND to minimize highand low-frequency
fluctuations. If the supply is excessively noisy, connect
a 5Ω resistor between the supply and V
Figure 15.
Figure 14a. Unipolar Transfer Function
00... 011
00... 010
00... 001
00... 000
11... 111
11... 110
11... 101
OUTPUT CODE
0
1
2
Layout, Grounding, and Bypassing
______________________________________________________________________________________
3
INPUT VOLTAGE (LSB)
FULL-SCALE
TRANSITION
DD
Transfer Function
with 0.1µF and 4.7µF
FS -
DD
3
/
, as shown in
2
LSB
1 LSB =
FS
Multirange, +5V, 8-Channel,
4096
FS
Figure 14b. Bipolar Transfer Function
Figure 15. Power-Supply Grounding Connections
011... 111
011... 110
000... 001
000... 000
111... 111
100... 010
100... 001
100... 000
*OPTIONAL
**CONNECT AGND AND DGND WITH A GROUND PLANE OR A SHORT TRACE.
R* = 5Ω
OUTPUT CODE
+5V
V
DD
Serial 12-Bit ADCs
-FS
0.1µF
4.7µF
AGND
MAX1270
MAX1271
INPUT VOLTAGE (LSB)
**
SUPPLY
0
DGND
+FS - 1 LSB
+5V
CIRCUITRY
DIGITAL
1 LSB =
GND
DGND
2|FS|
4096
17