LTC2914IGN-2 Linear Technology, LTC2914IGN-2 Datasheet - Page 10

• Manufacturer Part Number: LTC2914IGN-2
• Description: IC,Power Supply Supervisor,CMOS,SSOP,16PIN,PLASTIC
• Manufacturer: Linear Technology

Specifications of LTC2914IGN-2

• Voltage Supervisor Type: Voltage Monitor
• Number Of Voltage Supervisors: 4
• Operating Supply Voltage (min): 2.3V
• Operating Supply Voltage (max): 6.9V
• Package Type: SSOP N
• Operating Temperature Classification: Industrial
• Operating Temp Range: -40C to 85C
• Pin Count: 16
• Mounting: Surface Mount
• Lead Free Status / Rohs Status: Not Compliant

APPLICATIONS INFORMATION
LTC2914
For positive supply monitoring, V
nal operating voltage, I
through the resistive divider, I
current calculated using the 1% resistor R
desired overvoltage trip point and V
undervoltage trip point.
For negative supply monitoring, to compensate for the 1V
reference, 1V must be subtracted from V
before using each in the following equations.
1A. Choose R
1B. Calculate I
2. Choose R
3. Choose R
If any of the variables V
each step must be recalculated.
Positive Voltage Monitor Example
A positive voltage monitor application is shown in Figure 3.
The monitored voltage is a 5V ±10% supply. Nominal cur-
rent in the resistive divider is 10µA.
10
R
voltage monitor.
Once R
point for the undervoltage monitor.
Once R
R
I
R
R
na
A
B
C
A
is chosen to set the desired trip point for the over-
=
=
=
=
I
0.5V
0.5V
V
0.5V
na
R
A
I
A
n
I
na
n
A
is known, R
and R
A
B
C
– R
na
to Complete the Design
to obtain the desired OV trip point
to obtain the desired UV trip point
•
•
•
V
A
V
V
V
V
V
UV
OV
OV
B
– R
n
n
n
are known, R
– R
B
n
nd
, I
B
na
is chosen to set the desired trip
A
is the desired nominal current
, I
nd
na
, V
is the resistive divider
C
UV
n
is determined by:
is the desired nomi-
or V
UV
OV
n
is the desired
, V
A
change, then
. V
OV
OV
and V
is the
(1)
(2)
(3)
UV
1A. Find R
1B. Calculate I
2. Find R
3. Determine R
Negative Voltage Monitor Example 1
A negative voltage monitor application is shown in Figure 4.
The monitored voltage is a –5V ±10% supply. Nominal
current in the resistive divider is 10µA. For the negative
case, 1V is subtracted from V
1A. Find R
1B. Calculate I
2. Find R
R
I
R
R
I
R
R
na
no
B
C
B
A
A
=
=
=
=
•
=
=
45.3k
0.5V
46.4k
10.034µA
10.034µA
9.947µA
0.5V
A
10µA
B
10µA
0.5V
A
B
0.5V
0.5V
0.5V
to set the OV trip point of the monitor.
to set the UV trip point of the monitor.
to set the OV trip point of the monitor.
to set the UV trip point of the monitor.
5V
Figure 3. Positive Supply Monitor
na
na
•
5V ±10%
•
5.5V
•
C
•
5V
–5.5V – 1V
V1
5.5V
–5V – 1V
•
to complete the design.
–5.5V – 1V
5V
–5V – 1V
R
442k
R
10k
R
45.3k
•
–4.5V – 1V
– 45.3k − 10k ≈ 442k
C
B
A
–5V – 1V
4.5V
= 10.034µA
5V
≈ 45.3k
– 45.3k ≅ 10k
VH1
VL1
= 9.947µA
LTC2914
n
≈ 46.4k
− 46.4k ≅ 8.45k
GND
V
V
, V
5V
CC
CC
2914 F03
OV
SEL
OV
UV
and V
UV
.
2914fb