LTC2902_15 Datasheet, PDF (1/16 Pages) Linear Technology – Programmable Quad Supply Monitor with Adjustable Reset Timer and Supply Tolerance

LTC2902
Programmable Quad Supply
Monitor with Adjustable Reset Timer
and Supply Tolerance
FEATURES
DESCRIPTIO
s _{Simultaneously Monitors Four Supplies}
s _{16 User Selectable Combinations of 5V, 3.3V, 3V,}
2.5V, 1.8V, 1.5V and/or ±Adjustable Voltage
Thresholds
s _{Guaranteed Threshold Accuracy: ±1.5% of Monitored}
Voltage Over Temperature
s _{Selectable Supply Tolerance: 5%, 7.5%,}
10%, 12.5% Below Monitored Voltage
s _{Low Supply Current: 43µA Typ}
s _{Adjustable Reset Time}
s _{RESET Disable Pin for Margining Applications}
s _{Open-Drain RST Output (LTC2902-1)}
s _{Push-Pull RST Output (LTC2902-2)}
s _{Individual Nondelayed Monitor Outputs for Each Supply}
s _{Power Supply Glitch Immunity}
U ^{s Guaranteed RESET for VCC ≥ 1V}
APPLICATIO S
s _{Desktop and Notebook Computers}
s _{Multivoltage Systems}
s _{Telecom Equipment}
s _{Portable Battery-Powered Equipment}
s _{Network Servers}
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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Quad Supply Monitor with Adjustable Tolerance (5V, 3.3V, 2.5V, 1.8V)
5V
3.3V
DC/DC
CONVERTER
2.5V
1.8V
C1
0.1µF
C2
0.1µF
R1
59k
1%
R2
40.2k
1%
SYSTEM
LOGIC
4
V1
3
13
V3 V4
2
R3
10k
POWER
GOOD
COMP1
16
COMP2
14
V2
1
COMP3
15
LTC2902-2 COMP4
12
V_REF
6
RST
8
RDIS
MARGIN
11
V_PG
GND
10
7
T0
9
T1
CRT
5 _CRT
47nF
TOLERANCE = 5%
t_RST = 216ms
2902 TA01
2902f
1