Rainbow Electronics MAX1386 - Manual (Page 25)

MAX1385/MAX1386
Dual RF LDMOS Bias Controllers
with I 2 C/SPI Interface
______________________________________________________________________________________ 25
In single-conversion mode (CKSEL = 11), the BUSY
signal remains high until the ADC has completed the
current conversion (not the entire scan, just the current
conversion), the data has been moved into the FIFO,
and the alarm limits for the channel have been checked
(if enabled). In multiple-conversion mode (CKSEL = 01
or CKSEL = 00), the BUSY signal remains high until all
channels have been scanned and the data from the
final channel has been moved into the FIFO and
checked for alarm limits (if enabled). In continuous-con-
version mode (CONCONV = 1), the BUSY signal does
not go high as a result of ADC conversions; however,
BUSY does go high when CONCONV is removed and
remains high until the current scan is complete and the
ADC sequence halts.
After commanding any of the DAC autocalibration compo-
nents, wait for BUSY to go low before setting OSCPD to 1.
Alarm Modes
The MAX1385/MAX1386 contain several programmable
modes for configuring outputs ALARM, SAFE1, and
SAFE2 behavior. Window-threshold mode allows SAFE_
to assert when the temperature/current is too high or
too low (outside the window). Hysteresis-threshold
mode allows SAFE_ to assert when the temperature/
current is too high, and then to deassert when the tem-
perature/current falls back to an appropriate level.
ALARM asserts when SAFE1 and/or SAFE2 asserts.
Program ALARM for output-comparator mode to stay
asserted after an alarm condition until temperature/cur-
rent levels are back below programmed thresholds.
Program ALARM for output-interrupt mode to stay
asserted after an alarm condition until the Flag register
is read.
Window-Threshold Mode
In window-threshold mode, ADC readings of
current/temperature are compared to the configured
current/temperature low/high thresholds that are pro-
grammed to cause an alarm condition. If an ADC read-
ing falls out of the configured window and ALARM is
configured for output-comparator mode, ALARM
asserts until the current/temperature reading falls back
into the window (past the built-in hysteresis). If an ADC
reading falls out of the configured window and ALARM
is configured for output-interrupt mode, ALARM asserts
until the Flag register is read. Set the amount of built-in
hysteresis from 8 LSBs to 64 LSBs (see the
ALMSCFG
(Read/Write) section). See Figures 7 and 8.
MEASUREMENT VALUE
(TEMPERATURE OR CURRENT)
HIGH THRESHOLD
BUILT-IN HYSTERESIS
BUILT-IN HYSTERESIS
LOW THRESHOLD
ALARM OUTPUT
OUTPUT-
COMPARATOR MODE
(ACTIVE LOW)
OUTPUT-
INTERRUPT MODE
(ACTIVE LOW)
FLAG REGISTER
READ
FLAG REGISTER
READ
FLAG REGISTER
READ
TIME
TIME
Figure 8. Window-Threshold-Mode Timing Diagram