WARMUP

CONVERTION

CYCLES 2–12

REFERENCE

SAMPLING

SUBTRACTION

AND WRITE TO

OUTPUT REGISTER

CONVERTION CYCLES 1–12

WARMUP

INPUT

ACQUISITION

INPUT

ACQUISITION

SSTRB

FCLK

CONVERSION CYCLE 1

FIRST CONVERSION

SECOND CONVERSION

12-Bit Serial-Output Temperature Sensors

with 5-Channel ADC

______________________________________________________________________________________

13

maximum time the device takes to acquire the signal.

Calculate this with the following equation:

input sampling capacitance of the ADC (4pF). Source

impedances below 100k

Ω have no significant effect on

MAX1298/MAX1299 AC performance.

Analog Input Protection

Internal protection diodes clamp the analog inputs to

accurate conversions, the inputs should not extend

beyond the supply rails.

If an off-channel analog input extends beyond the

supply rails, limit the input current to 2mA.

Serial Digital Interface

The MAX1298/MAX1299 feature a serial interface that is

fully compatible with SPI, QSPI, and MICROWIRE

devices. For SPI/QSPI, ensure that the CPU serial inter-

face runs in master mode so it generates the serial

clock signal. Select a 2.5MHz clock frequency or less,

and set zero values for clock polarity (CPOL) and

phase (CPHA) in the µP control registers. Figure 4

shows detailed serial interface timing information. See

Tables 2–5 for programming information.

WARMUP

WRITE TO OUTPUT

REGISTER

INPUT

ACQUISITION

SSTRB

FCLK

REF

ACQUISITION 1

REF

ACQUISITION 2

CONVERSION CYCLE 1

CONVERSION CYCLES 2–12

REFERENCE SAMPLING

Figure 3b. Temperature Conversion Timing Diagram

Figure 3a. Voltage Conversion Timing Diagram