LTC2900-1IMS#TRPBF Linear Technology, LTC2900-1IMS#TRPBF Datasheet - Page 9

• Manufacturer Part Number: LTC2900-1IMS#TRPBF
• Description: IC MON SUPP QUAD OPEN DRN 10MSOP
• Manufacturer: Linear Technology
• Type: Multi-Voltage Supervisorr

Specifications of LTC2900-1IMS#TRPBF

• Number Of Voltages Monitored: 4
• Output: Open Drain or Open Collector
• Reset: Active Low
• Reset Timeout: 5 ms Minimum
• Voltage - Threshold: 16 Selectable Threshold Combinations
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIO S I FOR ATIO
Power-Up
The greater of V1, V2 is the internal supply voltage (V
On power-up, V
pin. This ensures that the RST output will be low as soon
as V1 or V2 reaches 1V. The RST output will remain low until
the part is programmed. After programming, if any one of
the V
be a logic low. Once all the V
olds, an internal timer is started and RST is released after
the programmed delay time. If V
the V3 input impedance will be low (1k typ).
Monitor Programming
The LTC2900 input voltage combination is selected by
placing the recommended resistive divider from V
GND and connecting the tap point to V
Figure 4. Table 1 offers recommended 1% resistor values
for the various modes. The last column in Table 1 specifies
optimum V
gramming with a ratiometric DAC.
During power-up, once V1 or V2 reaches 2.4V max, the
monitor enters a programming period of approximately
150 s during which the voltage on the V
and the monitor is configured to the desired input combi-
nation. Do not add capacitance to the V
after programming, the comparators are enabled and
supply monitoring will begin.
X
inputs is below its programmed threshold, RST will
PG
/V
Figure 4. Monitor Programming
CC
REF
LTC2900
will power the drive circuits for the RST
U
ratios ( 0.01) to be used when pro-
V
GND
V
REF
PG
8
7
6
U
X
inputs rise above their thresh-
CC
1%
R1
< (V3 – 1) and V
W
R2
1%
2900 F04
PG
PG
PG
pin. Immediately
pin is sampled
, as shown in
U
CC
< 2.4V,
REF
CC
to
).
Table 1. Voltage Threshold Programming
Supply Monitoring
The LTC2900 is a low power, high accuracy program-
mable quad supply monitoring circuit with a common
reset output and a manual reset input. Reset timing is
adjustable using an external capacitor. Single pin pro-
gramming selects 1 of 16 input voltage monitor combina-
tions. All four voltage inputs must be above predetermined
thresholds for the reset not to be invoked. The LTC2900
will assert the reset output during power-up, power-down
and brownout conditions on any one of the voltage inputs.
The inverting inputs on the V3 and/or V4 comparators are
set to 0.5V when the positive adjustable modes are se-
lected (Figure 5). The tap point on an external resistive
divider, connected between the positive voltage being
MODE
10
11
12
13
14
15
0
1
2
3
4
5
6
7
8
9
V1 (V) V2 (V) V3 (V) V4 (V) R1 (k ) R2 (k )
5.0
5.0
3.3
3.3
3.3
5.0
5.0
5.0
5.0
5.0
3.3
3.3
3.3
5.0
5.0
5.0
3.3
3.3
2.5
2.5
2.5
3.3
3.3
3.3
3.0
3.0
2.5
2.5
2.5
3.3
3.3
3.0
ADJ
ADJ
ADJ
ADJ
ADJ
1.5
2.5
2.5
2.5
2.5
1.8
1.8
1.8
1.8
1.8
1.8
–ADJ
–ADJ
–ADJ
–ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
1.8
1.5
1.5
Open
Short
93.1
86.6
78.7
71.5
66.5
59.0
53.6
47.5
40.2
34.8
28.0
22.1
16.2
9.53
LTC2900
Short
Open
9.53
22.1
28.0
34.8
40.2
47.5
53.6
66.5
71.5
78.7
86.6
93.1
16.2
59.0
0.000
0.094
0.156
0.219
0.281
0.344
0.406
0.469
0.531
0.594
0.656
0.719
0.781
0.844
0.906
1.000
V
V
REF
PG
9
2900f