LTC1536I View Datasheet(PDF) - Linear Technology
Part Name
Description
Manufacturer
LTC1536I Datasheet PDF : 12 Pages
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LTC1536
PIN FUNCTIONS
VCC3 (Pin 1): 3.3V Sense Input and Power Supply Pin for
the IC. Bypass to ground with ≥ 0.1µF ceramic capacitor.
VCC5 (Pin 2): 5V Sense Input. Used as gate drive for RST
output FET when the voltage on VCC5 is greater than the
voltage on VCC3.
VCCA (Pin 3): 1V Sense, High Impedance Input. Can be
used as a logic input with a 1V threshold. If unused it can
be tied to either VCC3 or VCC5.
GND (Pin 4): Ground.
RST (Pin 5): Reset Logic Output. Active high CMOS logic
output, drives high to VCC3, buffered compliment of RST.
An external pull-down on the RST pin will drive this pin high.
RST (Pin 6): Reset Logic Output. Active low, open-drain
logic output with weak pull-up to VCC3. Can be pulled up
greater than VCC3 when interfacing to 5V logic.
Asserted when one or more of the supplies are below trip
thresholds and held for 200ms after all supplies become
valid. Also asserted after PBR is held low for more than two
seconds and for an additional 200ms after PBR is released.
SRST (Pin 7): “Soft” Reset. Active low, open-drain logic
output with weak pull-up to VCC3. Can be pulled up greater
than VCC3 when interfacing to 5V logic. Asserted for 100µs
after PBR is held low for less than two seconds and released.
PBR (Pin 8): Pushbutton Reset. Active low logic input with
weak pull-up to VCC3. Can be pulled up greater than VCC3
when interfacing to 5V logic. When asserted for less than
two seconds, outputs a soft reset 100µs pulse on the SRST
pin. When PBR is asserted for greater than two seconds,
the RST output is forced low and remains low until 200ms
after PBR is released.
BLOCK DIAGRAM
PBR 8
VCC3 1
VCC3
7µA
TO POWER DETECT
AND VCC INTERNAL
PBR
TIMER
–
SOFT RESET
RESET
FAST
+
–
SLOW
+
+
FAST
–
VCC5 2
TO
POWER
DETECT
–
FAST
+
–
SLOW
+
VCCA 3
–
SLOW
+
GND 4
REF
6
VCC3
6µA
7 SRST
VCC3
VCC3
6µA
200ms
RESET
GENERATOR
POWER
DETECT/
GATE DRIVE
VCC5
6 RST
VCC3
5 RST
1326 BD
1536fa
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