LTC2938/LTC2939
1
293839ff
V1 (V) V2 (V) V3 (V) V4 (V) V5 (V) V6 (V)
5 3.3 2.5 1.8 ADJ ADJ
5 3.3 2.5 ADJ ADJ ADJ
5 3.3 1.8 ADJ ADJ ADJ
5 3.3 ADJ ADJ ADJ ADJ
5 3.3 ADJ
–ADJ ADJ ADJ
3.3 2.5 1.8 1.5 ADJ ADJ
3.3 2.5 1.8 ADJ ADJ ADJ
3.3 1.8 1.5 1.2 ADJ ADJ
3.3 1.8 1.5 ADJ ADJ ADJ
3.3 1.8 1.2 ADJ ADJ ADJ
3.3 2.5 ADJ ADJ ADJ ADJ
3.3 2.5 ADJ –ADJ ADJ ADJ
3.3 1.8 ADJ ADJ ADJ ADJ
3.3 1.8 ADJ –ADJ ADJ ADJ
3.3 1.5 ADJ ADJ ADJ ADJ
3.3 1.2 ADJ ADJ ADJ ADJ
TYPICAL APPLICATION
DESCRIPTION
Confi gurable 4- and 6-Supply
Monitors with Watchdog Timer
The LTC
®
2938/LTC2939 are confi gurable supply monitors
for systems with up to four or six supply voltages that need
watchdog supervision. One of sixteen preset or adjustable
voltage monitor combinations can be selected using an
external resistive divider connected to the program input.
The preset voltage thresholds are accurate to ±1.5% over
temperature. The LTC2938 and LTC2939 also feature ad-
justable inputs with a 0.5V nominal threshold.
The reset and watchdog timeout periods are adjustable
using external capacitors. 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. Each status output has
a weak internal pull-up and may be externally pulled up
to a user-defi ned voltage.
The 80μA supply current makes the LTC2938 and LTC2939
ideal for power conscious systems. The LTC2939 moni-
tors up to six supplies and the LTC2938 monitors up to
four supplies.
6-Supply Monitor 12V (ADJ), 5V, 3.3V, 2.5V, 1.8V, 1.2V (ADJ)
FEATURES
APPLICATIONS
n
Simultaneously Monitors Four (LTC2938) or Six
Supplies (LTC2939)
n
Sixteen User-Selectable Combinations of 5V, 3.3V,
2.5V, 1.8V, 1.5V, 1.2V and/or ± Adjustable Voltage
Thresholds
n
Guaranteed Threshold Accuracy: ±1.5%
n
Adjustable Reset and Watchdog Timeout
n
Low Supply Current: 80μA Typical
n
Power Supply Glitch Immunity
n
Guaranteed RST for V
CC
> 1V
n
High Temperature Operation to 125°C
n
12-Pin 4mm × 3mm DFN or 12-Lead MSOP
(LTC2938) and 16-Lead MSOP Package (LTC2939)
n
Desktop and Notebook Computers
n
Multivoltage Systems
n
Telecom Equipment
n
Network Servers
n
Automotive Control Systems
Voltage Confi guration Table
LTC2939
1.2V
1.8V
2.5V
3.3V
5V
12V
293839 TA01
t
RST
= 94ms
t
WD
= 940ms
C
WT
47nF
C
RT
47nF
RST
WDO
WDI
V
PG
V
REF
GND
CWT CRT
V1
V2
V3
V4
V5
V6
SYSTEM
LOGIC
R1
59k
1%
100k
1%
100k
1%
124k
1%
2150k
1%
R2
40.2k
1%
0.1μF
0.1μF
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 6967591, 7239251, 7119714.