MAX1302AEUG+ Maxim Integrated, MAX1302AEUG+ Datasheet - Page 25

• Manufacturer Part Number: MAX1302AEUG+
• Description: Analog to Digital Converters - ADC 16Bit, 8Ch, 4.096V Multi-In Serial ADC
• Manufacturer: Maxim Integrated

Specifications of MAX1302AEUG+

• Rohs: yes
• Number Of Channels: 8/4
• Architecture: SAR
• Conversion Rate: 115 kSPs
• Resolution: 16 bit
• Input Type: Single-Ended/Differential
• Snr: 90 dB
• Interface Type: SPI
• Operating Supply Voltage: 4.75 V to 5.25 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: TSSOP-24
• Maximum Power Dissipation: 1111.1 mW
• Number Of Converters: 1
• Voltage Reference: 4.096 V

• External-acquisition-mode control byte
• Internal-clock-mode control byte
• Reset byte
• Partial power-down-mode control byte
This prevents the MAX1302 from inadvertently exiting
full power-down mode because of a CS glitch in a noisy
digital environment.
The MAX1302 powers up in normal operation configured
for external clock mode with all circuitry active (Tables 7
and 8). Each analog input channel (CH0–CH7) is set for
single-ended conversions with a ±V
range (Table 6).
Allow the power supplies to stabilize after power-up. Do
not initiate any conversions until the power supplies
have stabilized. Additionally, allow 10ms for the internal
reference to stabilize when C
= 0.1µF. Larger reference capacitors require longer
stabilization times.
The MAX1302 operates with either an internal or external
reference. The reference voltage impacts the ADC’s FSR
(Figures 12, 13, and 14). An external reference is recom-
mended if more accuracy is required than the internal ref-
erence provides, and/or multiple converters require the
same reference voltage.
The MAX1302 contains an internal 4.096V bandgap refer-
ence. This bandgap reference is connected to REFCAP
through a nominal 5kΩ resistor (Figure 17). The voltage at
REFCAP is buffered creating 4.096V at REF. When using
Figure 17. Internal Reference Operation
MAX1302
SAR
ADC REF
REFERENCE
BANDGAP
4.096V
Internal or External Reference
5kΩ
______________________________________________________________________________________
4.096V
1x
8-Channel, ±V
REF
= 1.0µF and C
Power-On Reset
Internal Reference
REF
V
REFCAP
RCTH
AGND1
REF
bipolar input
RECAP
1.0µF
0.1µF
the internal reference, bypass REFCAP with a 0.1µF or
greater capacitor to AGND1 and bypass REF with a
1.0µF or greater capacitor to AGND1.
For external reference operation, disable the internal
reference and reference buffer by connecting REFCAP
to AVDD1. With AVDD1 connected to REFCAP, REF
becomes a high-impedance input and accepts an
external reference voltage. The MAX1302 external ref-
erence current varies depending on the applied refer-
ence voltage and the operating mode (see the External
Reference Input Current vs. External Reference Input
Voltage in the Typical Operating Characteristics ).
Additional samples can be taken and averaged (over-
sampling) to remove the effect of transition noise on
conversion results. The square root of the number of
samples determines the improvement in performance.
For example, with 2/3 LSB
noise, 16 (4
the noise to 1 LSB
Figure 19 illustrates a simple interface between the
MAX1302 and a 4–20mA signal. 4–20mA signaling can
be used as a binary switch (4mA represents a logic-low
signal, 20mA represents a logic-high signal), or for pre-
cision communication where currents between 4mA
and 20mA represent intermediate analog data. For
binary switch applications, connect the 4–20mA signal
to the MAX1302 with a resistor to ground. For example,
a 200Ω resistor converts the 4–20mA signal to a 0.8V to
4V signal. Adjust the resistor value so the parallel com-
bination of the resistor and the MAX1302 source
impedance is 200Ω. In this application, select the sin-
gle-ended 0V to V
For applications that require precision measurements
of continuous analog currents between 4mA and 20mA,
use a buffer to prevent the MAX1302 input from divert-
ing current from the 4–20mA signal.
REF
Multirange Inputs,
2
Serial 16-Bit ADC
= 16) samples must be taken to reduce
Applications Information
Interface with 4–20mA Signals
P-P
REF
.
range (R[2:0] = 011, Table 6).
RMS
(4 LSB
Noise Reduction
External Reference
P-P
) transition
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