LT1074CT Linear Technology, LT1074CT Datasheet - Page 10
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LT1074CT
Manufacturer Part Number
LT1074CT
Description
IC MULTI CONFIG ADJ 5A TO220-5
Manufacturer
Linear Technology
Type
Step-Down (Buck), Step-Up (Boost), Inverting, Flybackr
Datasheet
1.LT1076CTPBF.pdf
(16 pages)
Specifications of LT1074CT
Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
2.5 ~ 50 V
Current - Output
5A
Frequency - Switching
100kHz
Voltage - Input
8 ~ 45 V
Operating Temperature
0°C ~ 70°C
Mounting Type
Through Hole
Package / Case
TO-220-5 (Bent and Staggered Leads)
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Power - Output
-
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
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Part Number:
LT1074CT
Manufacturer:
LT
Quantity:
2 023
Part Number:
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Manufacturer:
LINEAR/凌特
Quantity:
20 000
Company:
Part Number:
LT1074CT#PBF
Manufacturer:
Linear
Quantity:
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Manufacturer:
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Quantity:
20 000
Company:
Part Number:
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Manufacturer:
LT
Quantity:
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Part Number:
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Quantity:
20 000
Part Number:
LT1074CT7#PBF
Manufacturer:
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Quantity:
20 000
SHUTDOWN
LT1074/LT1076
PI
Undervoltage Lockout
Undervoltage lockout point is set by R1 and R2 in Figure 6.
To avoid errors due to the 10µA shutdown pin current, R2
is usually set at 5k, and R1 is found from:
If quiescent supply current is critical, R2 may be increased
up to 15kΩ, but the denominator in the formula for R2
should replace V
10
V
V
R
U
TP
SH
1
PIN
=
DESCRIPTIO S
= Desired undervoltage lockout voltage
10 A
= Threshold for lockout on the
R
µ
2
shutdown pin = 2.45V
(
V
TP
2.3V
0.3V
Figure 6. Undervoltage Lockout
V
Figure 5. Shutdown Circuitry
−
SH
R1
R2
SH
5k
V
SH
with V
–
+
–
+
)
C1
C2
SH
U
– (10µA)(R2).
300 A
SHUT
µ
LT1074
GND
V
IN
Q1
TO TOTAL
REGULATOR
SHUTDOWN
LT1074•PD08
V
LT1074•PD07
IN
I
PIN
6V
LIM
EXTERNAL
C
LIM
Hysteresis in undervoltage lockout may be accomplished
by connecting a resistor (R3) from the I
shutdown pin as shown in Figure 7. D1 prevents the
shutdown divider from altering current limit.
If R3 is added, the lower trip point (V
the same. The upper trip point (V
If R1 and R2 are chosen, R3 is given by:
Example: An undervoltage lockout is required such that
the output will not start until V
to operate until V
R
R
R
Trip Po
V
UTP
1
3
3
=
=
=
(
=
V
20 2 35 1
2 34
(
UTP
.
*1N4148
(
int
V
2 35 0 8 12 5
V
−
SH
.
SH
k
=
R1
R2
−
⎛
⎜
⎝
)
.
1
−
−
(
Figure 7. Adding Hysteresis
V
V
R3
15
R
IN
R
TP
SH
0 8
⎛
⎜
⎝
2
1
.
.
V
drops to 15V. Let R2 = 2.32k.
⎛
⎜
⎝
2 35
=
+
V R
+
)( )
1
−
.
D1*
)( )
2 35
R
+
R
12 5
2 32
2 35
.
3
1
.
V
R
.
R
.
1
⎞
⎟ −
⎠
.
2
1
V
⎞
⎟
⎠
SHUT
V
⎞
⎟
⎠
I
LIM
⎛
⎜
⎝
0 8
)
=
1
IN
.
=
+
LT1074
OPTIONAL CURRENT
LIMIT RESISTOR
3 9
V
= 20V, but will continue
UTP
12 5
.
V
R
R
⎛
⎜
⎝
IN
IN
1
2
k
R
R
.
) will be:
⎞
⎟
⎠
descending) will be
3
1
k
⎞
⎟
⎠
LT1074•PD09
LIM
pin to the
sn1074 1074fds