Rainbow Electronics MAX6871 - Manual (Page 47)

Temperature Sensor Outputs
Figure 11 shows the MAX6870/MAX6871 in a tempera-
ture-sensing application with the DS600. The DS600
generates an analog output voltage proportional to the
sensed temperature through V
OUT
and logic outputs on
TO and TO (only TO is shown). The internal ADC of the
MAX6870/MAX6871 digitizes the analog output voltage
of the DS600 and stores the results in read-only regis-
ters 5Ch through 5Fh. V
TH sets the threshold voltage
that V OUT must exceed for TO to generate a logic-high
signal. V
TH
must be less than 1.25V, otherwise the
overcurrent condition will occur after the internal ADC
attains its full-scale input voltage. Configure GPI1 as an
active-high input and configure PO7 (MAX6870)/PO5
(MAX6871) to depend on GPI1. When V
OUT increases
above V TH , TO asserts high, causing PO7/PO5 to
assert to its active state.
Monitoring Other Voltages
Use AUXIN_ to monitor any voltage up to 1.25V. The
internal ADC of the MAX6870/MAX6871 digitizes the volt-
age and stores the results in read-only registers 5Ch
through 5Fh. The internal ADC cycles through the volt-
age monitor inputs and the auxiliary inputs every 200ms.
Layout and Bypassing
For better noise immunity, bypass each of the voltage
detector inputs to GND with 0.1µF capacitors installed
as close to the device as possible. Bypass ABP and
DBP to GND with 1µF capacitors installed as close to
the device as possible. ABP and DBP are internally
generated voltages and should not be used to supply
power to external circuitry.
Configuration Latency Period
A delay of less than 5µs occurs between writing to the
configuration registers and the time when these
changes actually take place, except when changing
one of the voltage-detector thresholds. Changing a
voltage-detector threshold typically takes 150µs. When
changing EEPROM contents, a software reboot or
cycling of power is required for these changes to trans-
fer to volatile memory.
Chip Information
PROCESS: BiCMOS
MAX6870/MAX6871
EEPROM-Programmable Hex/Quad
Power-Supply Sequencers/Supervisors with ADC
______________________________________________________________________________________ 47
IN3
+5V
GND
AUXIN1
GPI1
CTG
V TH
V OUT
V TH
(<1.25V) TO
GND
V DD
MAX6870
MAX6871
PO5/
PO3
DS600
R PU
Figure 11. Temperature Sensor Outputs