LTC2902-2CGN Linear Technology, LTC2902-2CGN Datasheet - Page 11

• Manufacturer Part Number: LTC2902-2CGN
• Description: IC MON SUPP QD W/RST&SEL 16-SSOP
• Manufacturer: Linear Technology
• Type: Multi-Voltage Supervisorr

Specifications of LTC2902-2CGN

• Number Of Voltages Monitored: 4
• Output: Push-Pull, Totem Pole
• Reset: Active Low
• Reset Timeout: 5 ms Minimum
• Voltage - Threshold: 16 Selectable Threshold Combinations
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 16-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIO S I FOR ATIO
In the negative adjustable mode, the noninverting input on
the V4 comparator is connected to ground (Figure 6). The
tap point on an external resistive divider, connected be-
tween the negative voltage being sensed and the V
is connected to the high impedance inverting input (V4).
V
at ground. The trip voltage is calculated from:
Once the resistor divider is set in the 5% tolerance mode,
there is no need to change the divider for the other
tolerance modes (7.5%, 10%, 12.5%) because V
scaled accordingly, moving the trip point in – 2.5%
increments.
In a negative adjustable application, the minimum value
for R4 is limited by the sourcing capability of V
With no other load on V
Tables 2 and 3 offer suggested 1% resistor values for
various adjustable applications.
REF
1.21V 1mA = 1.21k
T0,T1 Low (5% Tolerance Mode)
V
TRIP
provides the necessary level shift required to operate
Figure 5. Setting the Positive Adjustable Trip Point
Figure 6. Setting the Negative Adjustable Trip Point
V3 OR V4
V
–
TRIP
V
V
R4
1%
R3
1%
REF
TRIP
R3
1%
R4
1%
12
13
R
U
R
3
4
V
V4
REF
;
REF
V
U
+
–
REF
, R4 (minimum) is:
–
+
0.5V
5% TOLERANCE MODE
LTC2902
+
–
LTC2902
1 210
.
W
V
2902 F06
2902 F05
REF
U
( 1mA).
REF
REF
pin,
is
Table 2. Suggested 1% Resistor Values for the ADJ Inputs
Table 3. Suggested 1% Resistor Values for the –ADJ Input
Although all four supply monitor comparators have built-in
glitch immunity, bypass capacitors on V1 and V2 are
recommended because the greater of V1 or V2 is also the
V
are allowed.
Power-Down
On power-down, once any of the V
their threshold, RST and COMPX are held at a logic low.
A logic low of 0.4V is guaranteed until both V1 and V2
drop below 1V. If the bandgap reference becomes invalid
(V
above 2.4V (max).
Monitor Output Rise and Fall Time Estimation
All of the outputs (RST, COMPX) have strong pull-down
capability. If the external load capacitance (C
CC
CC
V
V
SUPPLY
SUPPLY
for the chip. Filter capacitors on the V3 and V4 inputs
–5.2
< 2V typ), the part will reprogram once V
–10
–12
7.5
3.3
2.5
1.8
1.5
1.2
0.9
–2
–5
12
10
8
6
5
3
1
(V)
(V)
V
V
–11.30
TRIP
TRIP
11.25
4.725
3.055
2.325
1.685
1.410
1.120
0.933
0.840
–1.87
–4.64
–4.87
–9.31
2.82
9.4
7.5
5.6
7
(V)
(V)
R3 (k )
R3 (k )
2150
1780
1400
1300
1020
1130
86.6
68.1
845
511
464
365
237
182
124
187
464
487
931
X
inputs drop below
LTC2902
LOAD
R4 (k )
R4 (k )
100
100
100
100
100
100
100
100
100
100
100
100
100
100
121
121
121
121
121
CC
11
) for a
rises
2902f