LTC2904 Datasheet, PDF (1/16 Pages) Linear Technology – Precision Dual Supply Monitors with Pin-Selectable Thresholds

FEATURES
■ _{Monitors Two Inputs Simultaneously}
■ _{Nine Threshold Combinations}
■ _{Three Supply Tolerances (5%, 7.5%, 10%)}
■ _{Guaranteed Threshold Accuracy: ±1.5% of}
Monitored Voltage Over Temperature
■ _{Internal VCC Auto Select}
■ _{Power Supply Glitch Immunity}
■ _{200ms Reset Time Delay (LTC2904 Only)}
■ _{Adjustable Reset Time Delay (LTC2905 Only)}
■ _{Open Drain RST Output}
■ _{Guaranteed RST for V1 ≥ 1V or V2 ≥ 1V}
■ _{Low Profile (1mm) SOT-23 (ThinSOT}^TM_{) and Plastic}
(3mm x 2mm) D_UFN Packages
APPLICATIO S
■ _{Desktop and Notebook Computers}
■ _{Handheld Devices}
■ _{Network Servers}
■ _{Core, I/O Monitor}
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
LTC2904/LTC2905
Precision Dual Supply Monitors
with Pin-Selectable Thresholds
DESCRIPTIO
The LTC^®2904/LTC2905 are dual supply monitors in-
tended for systems with two supply voltages. The dual
supply monitors have a common reset output with delay
(200ms for the LTC2904 and adjustable using an external
capacitor for the LTC2905). This product provides a
precise, space-conscious and micropower solution for
supply monitoring.
The LTC2904/LTC2905 feature a tight 1.5% threshold
accuracy over the whole operating temperature range,
and glitch immunity to ensure reliable reset operation
without false triggering. The open drain RST output is
guaranteed to be in the correct state for inputs down to 1V.
The LTC2904/LTC2905 also feature three programming
input pins, which program the threshold and tolerance
level without requiring any external components. These
three programming pins provide a total of 27 different
voltage level and tolerance combinations, eliminating
the need to have different parts for development and
implementation of different systems with different voltage
levels requiring monitoring function.
TYPICAL APPLICATIO
5V, 3.3V Dual Supply Monitor with 5% Tolerance
5V
DC/DC
SYSTEM
CONVERTER
3.3V
LOGIC
0.1µF
V1
V2
LTC2905
S1
TMR
S2
GND
TOL
RST
0.1µF
22nF
29045 TA01
Table 1. Voltage Threshold Programming
V1
V2
S1
S2
5.0
3.3
V1
V1
3.3
2.5
Open
GND
3.3
1.8
V1
Open
3.3
1.5
Open
V1
3.3
1.2
Open
Open
2.5
1.8
GND
GND
2.5
1.5
GND
Open
2.5
1.2
GND
V1
2.5
1.0
V1
GND
sn29045 29045fs
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