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LTC2902
2902f
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
Programmable Quad Supply
Monitor with Adjustable Reset Timer
and Supply Tolerance
■
Simultaneously Monitors Four Supplies
■
16 User Selectable Combinations of 5V, 3.3V, 3V,
2.5V, 1.8V, 1.5V and/or ±Adjustable Voltage
Thresholds
■
Guaranteed Threshold Accuracy: ±1.5% of Monitored
Voltage Over Temperature
■
Selectable Supply Tolerance: 5%, 7.5%,
10%, 12.5% Below Monitored Voltage
■
Low Supply Current: 43µA Typ
■
Adjustable Reset Time
■
RESET Disable Pin for Margining Applications
■
Open-Drain RST Output (LTC2902-1)
■
Push-Pull RST Output (LTC2902-2)
■
Individual Nondelayed Monitor Outputs for Each Supply
■
Power Supply Glitch Immunity
■
Guaranteed RESET for V
CC
≥ 1V
The LTC
®
2902 is a programmable supply monitor for sys-
tems with up to four supply voltages. One of 16 preset or
adjustable voltage monitor combinations can be selected
using an external resistor divider connected to the pro-
gram pin. The preset voltage thresholds are digitally pro-
grammable to 5%, 7.5%, 10% or 12.5% below the nomi-
nal operating voltage, and are accurate to 1.5% over tem-
perature. All four voltage comparator outputs are con-
nected to separate pins for individual supply monitoring.
The reset delay time is adjustable using an external
capacitor. Tight voltage threshold accuracy and glitch
immunity ensure reliable reset operation without false
triggering. The RST output is guaranteed to be in the
correct state for V
CC
down to 1V and may be disabled
during supply margin testing. The LTC2902-1 features
an open-drain RST output, while the LTC2902-2 has a
push-pull RST output.
The 43µA supply current makes the LTC2902 ideal for power
conscious systems and the part may be configured to
monitor less than four inputs. The LTC2902-1/LTC2902-2
are available in the 16-lead narrow SSOP package.
Quad Supply Monitor with Adjustable Tolerance (5V, 3.3V, 2.5V, 1.8V)
■
Desktop and Notebook Computers
■
Multivoltage Systems
■
Telecom Equipment
■
Portable Battery-Powered Equipment
■
Network Servers
, LTC and LT are registered trademarks of Linear Technology Corporation.
V1
V2
V
REF
V
PG
COMP1
COMP2
COMP3
COMP4
RST
RDIS
T0
T1
GND
10
11
R1
59k
1%
R3
10k
POWER
GOOD
R2
40.2k
1%
12
7
9
8
6
15
1
16
2
133
14
4
5
C
RT
47nF
C2
0.1µF
C1
0.1µF
V4V3
LTC2902-2
CRT
t
RST
= 216ms
MARGIN
TOLERANCE = 5%
2902 TA01
DC/DC
CONVERTER
1.8V
2.5V
3.3V
5V
SYSTEM
LOGIC
Verzeichnis
