MAX1202EVKIT Maxim Integrated Products, MAX1202EVKIT Datasheet - Page 3

• Manufacturer Part Number: MAX1202EVKIT
• Description: EVALUATION KIT FOR MAX1202
• Manufacturer: Maxim Integrated Products

Specifications of MAX1202EVKIT

• Number Of Adc's: 1
• Number Of Bits: 12
• Sampling Rate (per Second): 133k
• Data Interface: Serial
• Inputs Per Adc: 8 Single or 4 Differential
• Input Range: ±VREF/2
• Power (typ) @ Conditions: 7.5mW @ 133kSPS
• Voltage Supply Source: Dual ±
• Operating Temperature: 0°C ~ 70°C
• Utilized Ic / Part: MAX1202, MAX1203
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

The MAX1202 can be shut down between conversions
to reduce average supply-current demand. From the
“Power” menu, select full power-down (FULLPD) or fast
power-down (FASTPD) mode. In fast power-down
mode, the bandgap reference remains active. The
amount of power saved depends primarily on how long
the part is off between conversions. The conversion
accuracy depends on the power-up delay, the refer-
ence capacitor, and the time in power-down. Adjust off-
time with the “Delay Between Samples” command.
Adjust on-time with the “Power-Up Delay” command.
Using an adequate power-up delay ensures conversion
accuracy during power-cycling modes. The reference
must be allowed enough time to stabilize before the
measurement is performed. The “Power-Up Delay”
command controls power-up delay. Increase the delay
until accuracy is constant. The power-up delay require-
ment depends on the off-time (delay between samples)
and the value of the reference capacitor (C12).
The MAX1202 EV kit software performs power-up by
starting a conversion in FASTPD mode and discarding
the reading. FASTPD mode turns on the reference, but
leaves the MAX1202’s other circuitry powered down.
An accurate reference-voltage measurement can be
performed after the power-up delay is complete.
The MAX1203 requires an external reference, so
FULLPD mode can always be used, assuming the exter-
nal reference is always stable when measurements are
performed. In this case, set power-up delay to 0.
On the EV board, the MAX1202 draws all of its +5V
analog power through jumper JU4, which is wired
closed when the board is shipped from the factory. To
measure the MAX1202’s supply current, modify the
board (with the power off) by cutting jumper JU4 and
connecting a current meter across JU4.
The RS-232 serial link limits the data-logging sample
rate to no more than 10 samples/sec. The “Log” menu
can be used to write data to a user-specified file in
comma-spaced-value text format. From the “Log”
menu, choose “Select Channels”, and select the chan-
nels you want to log. Then choose the “New Log File”
command from the “Log” menu. Once a log file has
been opened, it can be paused or resumed with the
“Pause” command. One complete line of data is written
after all enabled channels have been sampled. The first
line of the log file contains the column headings. Each
__Detailed Description of Software
_______________________________________________________________________________________
Measuring Supply Current
Shutdown Power Cycling
Low-Speed Data Logging
MAX1202 Evaluation Kit
subsequent line of the log file contains all enabled
channels, separated by commas, tabs, or spaces. The
program continues to write data to the log file until the
“Done” command is selected from the “Log” menu.
The high-speed sampling commands can be used for
sampling rates over 10 samples/sec. Data can be col-
lected from any single channel at high speed, using the
commands on the “Sample” menu. First select the num-
ber of samples. Then set the sampling rate either by
inserting a delay between samples, or by choosing one
of the preset sample rates. Use the “Collect” command
to begin collecting data. After the samples are collect-
ed, the data is automatically uploaded to the host and
graphed. Additionally, the data can be saved to a file.
The MAX1202 EV kit software assumes a 4.096V refer-
ence voltage, unless otherwise specified. The refer-
ence-voltage assumption can be changed using “Set
Reference Voltage” under the “Device” menu.
If an external reference is used, it must have a tempera-
ture coefficient of 20ppm/°C or less to achieve accuracy
to within four LSBs over the 0°C to +70°C range. For 12-
bit accuracy over this range, the reference must have a
temperature coefficient of 4ppm/°C or less.
The MAX1202 (U1) is an 8-channel, 12-bit, low-power
analog-to-digital converter (ADC) with serial interface
and shutdown. R1–R8 and C1–C8 are anti-aliasing
input filters. The analog supply rails are VDD, VSS, and
GND. The digital interface is powered by the VL pin.
The SHDN jumper controls hardware shutdown and
selects internal/external-compensation mode. Refer to
the MAX1202 data sheet for more information.
The ICL7660 (U2) is a charge pump that converts +5V
to -5V for V
The 78L05 (U3) is a +5V linear regulator that provides a
clean analog supply for the MAX1202.
The MAX1202 EV kit has an RC filter on each input with
a time constant (
C = 0.01µF). The MAX1202’s acquisition time with a
2MHz clock is 1.5µs. The RC filter’s settling time can
increase the acquisition time required for full accuracy
when switching input channels.
________________________of Hardware
SS
.
Changing the Reference Voltage
) of approximately 3µs (R = 300Ω,
High-Speed Data Sampling
Detailed Description
Input Filtering
Components
3