MAX11358B Datasheet, PDF (32/70 Pages) Maxim Integrated Products – 16-Bit Data-Acquisition System with ADC, DAC, UPIOs, RTC, Voltage Monitors, and Temp Sensor

16-Bit Data-Acquisition System with ADC, DAC,
UPIOs, RTC, Voltage Monitors, and Temp Sensor
M32K
32.768kHz
HFCE
FLLE
FREQUENCY
COMPARE
FREQ
ERROR
FREQUENCY
INTEGRATOR
TUNE<8:0> DIGITALLY
CONTROLLED
OSCILLATOR
CKSEL2
CKSEL<1:0>
CLKE
0
2:1
1, 2, 4, 8
MUX
DIVIDER
CLK
1
4.9152MHz
4.9152MHz HF OSCILLATOR AND FLL
HFCLK
CRDY
Figure 12. High-Frequency Clock and FLL Block Diagram
Program each UPIO1–UPIO4 as one of the following:
• General-purpose input
• Power-mode control
• Analog switch (SPST) and SPDT control input
• ADC data-ready output
• General-purpose output
• PWM output
• Alarm output
• SPI pass-through
Internal and External (Remote)
Temperature Sensors
An internal transistor or a remote transistor (or diode) is
used with the ADC and a programmable current source
to measure the ambient temperature. Depending on the
method, either two or four currents are passed through
the PN junction. The voltage across the PN junction is
measured at each current. For each current, the voltage
across a series resistor is also measured. Measuring the
voltage across the resistor allows the user to determine
the precise current ratios. A microcontroller can then
use the diode equation to calculate the temperature.
The four-current method eliminates errors caused by
parasitic resistance in series with the diode, which
increases the apparent voltage across the PN junction.
When measuring temperature using the internal transis-
tor for a sensor, the two-current method is usually ade-
quate although the four-current method can also be
used. Refer to Application Note 4296: Measuring
Temperature with the MAX1358 Data Acquisition System
for details on the measurement procedure.
PROGRAMMABLE CURRENT SOURCE
IVAL<1:0>
CURRENT
SOURCE
IMUX<1:0>
1:3
DEMUX
AIN1
AIN1
AIN2
AIN2
TEMP+
TEMP-
TEMP SENSOR
Figure 13. Temperature-Sensor Measurement Block Diagram
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