MAX11014 Datasheet, PDF (64/69 Pages) Maxim Integrated Products – Automatic RF MESFET Amplifier Drain-Current Controllers

Automatic RF MESFET Amplifier
Drain-Current Controllers
CNVST
tCNV11
tACQ11
tACQ11
BUSY
INTERNALLY*
INT REFERENCE POWERS UP IN 45μs
TEMP CONVERSION IN 30μs
IDLE, BUT REFERENCE
AND TEMPERATURE
SENSOR STAY
POWERED UP
IDLE, BUT REFERENCE
AND TEMPERATURE
SENSOR STAY
POWERED UP
END OF SCAN,
REFERENCE AND
TEMPERATURE SENSOR
POWER DOWN
AUTOMATICALLY
WRITE TO THE ADC
CONVERSION REGISTER TO
SET UP THE SCAN
CH0 (INTERNAL
TEMPERATURE) RESULT
LOADED INTO THE FIFO
*ALL TIMING SPECIFICATIONS ARE TYPICAL.
CLOCK MODE 11 EXAMPLE 1: COMMAND A SCAN OF CHANNELS 0, 5, AND 10 WITH AN INTERNAL REFERENCE.
Figure 31. Clock Mode 11 Timing Example 1
CH5 LOADED
INTO THE FIFO
CH10 LOADED
INTO THE FIFO
Clock Mode 01
In clock mode 01, power-up, acquisition, conversion,
and power-down are all initiated by a single CNVST low
pulse and performed automatically using the internal
oscillator. Initiate a scan by writing to the ADC conver-
sion register to indicate which channels to convert.
Then set CNVST low for at least 20ns only once to con-
vert all of the channels selected in the ADC conversion
register. With ADCMON set to 1, the ADC sets the
BUSY output high, powers up, scans all requested
channels, stores the results in the FIFO, and powers
down. After the scan is complete, the BUSY output is
pulled low and the results are available in the FIFO.
Externally Timed Acquisitions and
Conversions
Clock Mode 10
Clock mode 10 is reserved. Do not use this clock mode.
Clock Mode 11
In clock mode 11, conversions are initiated by CNVST
one at a time and performed using the internal oscilla-
tor. See Figures 31 and 32 for a pair of clock mode 11
timing examples. Initiate a conversion by writing to the
ADC conversion register and pulling CNVST low for at
least 1.5µs for each channel converted. Different timing
parameters apply to whether the conversion is a tem-
perature, a voltage using the external reference, or a
voltage using the internal reference conversion.
Internal and external temperature conversions are inter-
nally timed. Set CNVST low for at least 20ns to acquire
a temperature conversion. The BUSY output goes high
while sampling and the internal reference typically
requires 45µs to power up. The temperature sensor cir-
cuit requires 5µs to power up. Temperature conversion
results are available after an additional 30µs. The typi-
cal conversion time of the initial temperature sensor
scan is 80µs. Subsequent temperature scans only take
30µs typically as the internal reference and tempera-
ture sensor circuits are already powered. See the
Electrical Characteristics table for more details.
Set CNVST low for at least 1.5µs to acquire a voltage
conversion using the external reference. The BUSY out-
put goes high while sampling and the conversion
results are available after an additional 3.5µs (typ).
Set CNVST low for at least 50µs to trigger an initial volt-
age conversion using the internal reference. The BUSY
output goes high and the conversion results are avail-
able after an additional 3.5µs typically. Additional volt-
age conversions do not require the acquisition time of
powering up the internal reference. Set CNVST low for
at least 1.5µs to power up the ADC and place it in track
mode. The BUSY output goes high while sampling and
the conversion results are available after 5.6µs.
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