LTC2904 Linear Technology, LTC2904 Datasheet - Page 7

• Manufacturer Part Number: LTC2904
• Description: (LTC2904 / LTC2905) Precision Dual Supply Monitors
• Manufacturer: Linear Technology

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PI FU CTIO S
BLOCK DIAGRA
V2 (Pin 1/Pin 4): Voltage Input 2. Input for V2 monitor.
Select from 3.3V, 2.5V, 1.8V, 1.5V, 1.2V or 1.0V. Refer to
Table 1 for details. The greater of V1, V2 is also the internal
supply voltage, V
(or greater) capacitor.
RST (Pin 2/Pin 3): (LTC2904 Only) Reset Logic Output.
When all voltage inputs are above the reset threshold for
at least the programmed delay time, this pin pulls low. This
pin has a weak pull-up to V
using an external pull-up.
TMR (Pin 2/Pin 3): (LTC2905 Only) Reset Delay Time
Programming Pin. Attach an external capacitor (C
GND to set a reset delay time of 9ms/nF. Leaving the pin
open generates a minimum delay of approximately 200µs.
A 22nF capacitor will generate a 200ms reset delay time.
RST (Pin 3/Pin 2): Inverted Reset Logic Output. Pulls low
when any voltage input is below the reset threshold and is
held low for programmed delay time after all voltage
U
U
CC
V1
V2
. Bypass this pin to ground with a 0.1µF
U
LTC2904
REFERENCE
BAND GAP
POWER
DETECT
(TS8 Package/DDB8 Package)
CC
W
and may be pulled above V
V
CC
RESISTOR
NETWORK
TMR
–
+
–
+
) to
S1
CC
THREE-STATE DECODER
inputs are above threshold. This pin has a weak pull-up
to V
pull-up.
GND (Pin 4/Pin 1, Pin 9): Ground.
TOL (Pin 5/Pin 8): Three-state Input for Supply Tolerance
Selection (5%, 7.5% or 10%). See the Applications Infor-
mation section for tolerance selection chart (Table 2).
S1 (Pin 6/Pin 7): Voltage Threshold Select Three-State
Input. Connect to V1, GND or leave unconnected in open
state (See Table 1).
S2 (Pin 7/Pin 6): The Second Voltage Threshold Select
Three-State Input. Connect to V1, GND or leave uncon-
nected in open state (See Table 1).
V1 (Pin 8/Pin 5): Voltage Input 1. Input for V1 monitor.
Select from 5V, 3.3V, or 2.5V. See Table 1 for details. The
greater of V1, V2 is also the internal supply voltage, V
Bypass this pin to ground with a 0.1µF (or greater)
capacitor.
CC
S2
and may be pulled above V
RESET PULSE
GENERATOR
200ms
TOL
LTC2904/LTC2905
6µA
6µA
V
V
CC
CC
2904 BD
CC
RST
RST
GND
using an external
sn29045 29045fs
7
CC
.