MAX11359A Datasheet, PDF (30/66 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 passthrough
Temperature Sensor
The internal temperature sensor measures die tempera-
ture, and the external temperature sensor measures
remote temperatures. Use the internal temperature sen-
sor or external temperature sensor (remote transistor/
diode) with the ADC and internal current sources to
measure the temperature. For either method, two to four
currents are passed through a p-n junction and sense
resistor, and its temperature is calculated by a µC
using the diode equation and the forward-biased junc-
tion voltage drops measured by the ADC. The tempera-
ture offset between the internal p-n junction and
ambient is negligible. For the four and eight measure-
ment methods, the ratio of currents used in the diode
calculations is precisely known since the ADC mea-
sures the resulting voltage across the same sense
resistor. See Figure 13 for a block diagram of the tem-
perature sensor.
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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