LTC2914IGN-2 Linear Technology, LTC2914IGN-2 Datasheet - Page 11

• 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
3. Determine R
Negative Voltage Monitoring Example 2
Negative voltage monitoring applications with wide operat-
ing voltage ranges such that:
create situations where the VH or VL pins exceeds the
–0.3V absolute maximum voltage ratings. To ensure that
the LTC291X operates within its design specifications,
utilize the equations shown below to determine proper
resistor sizing for the circuit in Figure 5. In the following
example, the undervoltage trip point is –6V. The overvolt-
age trip point is –30V.
1A. Find R
1B. Calculate I
2 • V
which ensures that the diode current will not affect the
voltage monitor threshold accuracy. Let the resistive
divider current I
R
R
R
I
na
C
AUV
AUV
=
=
UV
V
–5V – 1V
9.947µA
AUV
=
= R
REF
< V
–5V ±10%
V
R
Figure 4. Negative Supply Monitor
BUV
and R
REF
V3
na
AUV
OV
– 0.5V
R
46.4k
R
8.45k
R
549k
C
using the resistor values chosen above.
A
B
C
I
nd
– 0.5V
to complete the design.
BUV
nd
− 46.4k − 8.45k ≈ 549k
= 10µA.
=
REF
VH3
VL3
and let node A be a virtual ground,
1V – 0.5V
=
LTC2914
GND
V
R
V
5V
CC
1V – 0.5V
CC
AUV
2914 F04
10µA
SEL
OV
UV
≈ 10.020µA
≈ 49.9k
2. Calculate R
3. Calculate R
4. Calculate R
Power-Up/Power-Down
As soon as V
asserts low and the OV output weakly pulls to V
The LTC2914 is guaranteed to assert UV low and OV high
under conditions of low V
2V (2.1V maximum) the VH and VL inputs take control.
Once all VH inputs and V
is started. After an adjustable delay time, UV weakly pulls
high.
Figure 5. Negative Supply Monitor for Wide Operating Range
point of –6V.
–30V.
I
R
(49.9k + 49.9k) •
R
R
na
BOV
CUV
AOV
≈ 10.020µA
= (R
=
=
0.5V – V
D1
V
CC
REF
AUV
CUV
AOV
BOV
reaches 1V during power-up, the UV output
I
na
I
nd
– 0.5V
+ R
R
49.9k
R
49.9k
A
R
698k
based on the desired undervoltage trip
and I
for a desired overvoltage trip point of
AUV
BUV
CUV
OV
BUV
–6V – 1V
na
=
R
49.9k
R
3.01M
CC
1V
AOV
CC
BOV
) •
=
V3
0.5V – 30 – 1
, down to V
become valid an internal timer
10.020µA
1V – 0.5V
V
V
REF
UV
10µA
REF
VH3
VL3
≈ 698k
LTC2914
=
GND
V
V
5V
CC
CC
CC
≈ 49.9k
LTC2914
SEL
OV
UV
= 1V. Above V
≈ 3.01M
2914 F05
CC
11
.
2914fb
CC
=