8
LTC2902
2902f
UU
U
PI FU CTIO S
RST (Pin 6): Reset Logic Output. Active low with weak
pull-up to V2 (LTC2902-1) or active pull-up to V2
(LTC2902-2). Pulls low when any voltage input is below
the reset threshold and held low for programmed delay
time after all voltage inputs are above threshold. May be
pulled above V2 using an external pull-up (LTC2902-1
only).
T0 (Pin 7): Digital Input for Supply Tolerance Selection
(5%, 7.5%, 10% or 12.5%). Used in conjunction with T1
(Pin 9). See Applications Information for tolerance selec-
tion chart (Table 4).
RDIS (Pin 8): Digital Input for RST Disable. A low input on
this pin forces the RST output to V2 (or pull-up voltage).
Useful for determining supply margins without issuing
reset command to processor. A weak internal pull-up
allows pin to be left floating for normal monitor operation.
T1 (Pin 9): Digital Input for Supply Tolerance Selection
(5%, 7.5%, 10% or 12.5%). Used in conjunction with T0
(Pin 7). See Applications Information for tolerance selec-
tion chart (Table 4).
GND (Pin 10): Ground.
V
PG
(Pin 11):
Voltage Threshold Combination Select
Input. Connect to an external 1% resistive divider be-
tween V
REF
and GND to select 1 of 16 combinations of
preset and/or ±adjustable voltage thresholds (see Table␣ 1).
Do not add capacitance on the V
PG
pin.
V
REF
(Pin 12): Buffered Reference Voltage. A 1.210V
nominal reference used for programming voltage (V
PG
)
and for the offset of negative adjustable applications. The
buffered reference can source and sink up to 1mA. The
reference can drive a bypass capacitor of up to 1000pF
without oscillation.
V4 (Pin 13): Voltage Input 4. Select from 1.8V, 1.5V, ADJ
or –ADJ. See Table 1 for details.
V2 (Pin 14): Voltage Input 2. Select from 3.3V, 3V or 2.5V.
See Table 1 for details. The greater of (V1, V2) is also V
CC
for chip. Bypass this pin to ground with a 0.1µF (or greater)
capacitor. All logic outputs (COMP1, COMP2, COMP3,
COMP4) are weakly pulled up to V2. RST is weakly pulled
up to V2 in the LTC2902-1 and RST is actively pulled up to
V2 in the LTC2902-2.
COMP4 (Pin 15): Comparator Output 4. Nondelayed,
active high logic output with weak pull-up to V2. Pulls high
when V4 is above reset threshold. May be pulled greater
than V2 using external pull-up.
COMP2 (Pin 16): Comparator Output 2. Nondelayed,
active high logic output with weak pull-up to V2. Pulls high
when V2 is above reset threshold. May be pulled greater
than V2 using external pull-up.
