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LT1071CT

Part # LT1071CT
Description IC REG MULT CONFIG INV ADJ TO220
Category IC
Availability In Stock
Qty 2
Qty Price
1 + $2.55601
Manufacturer Available Qty
Linear Technology
Date Code: 8815
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Technical Document


DISCLAIMER: The information provided herein is solely for informational purposes. Customers must be aware of the suitability of this product for their application, and consider that variable factors such as Manufacturer, Product Category, Date Codes, Pictures and Descriptions may differ from available inventory.

4
LT1070/LT1071
TYPICAL PERFORMANCE CHARACTERISTICS
UW
Switch Current Limit vs Duty Cycle
DUTY CYCLE (%)
0
SWITCH CURRENT (A)
16
14
12
10
8
6
4
2
0
80
1070/71 G01
20 40 60 1007010 30 50 90
FOR LT1071, DIVIDE
VERTICAL SCALE BY 2
–55°C
125°C
25°C
Flyback Blanking Time
JUNCTION TEMPERATURE (°C)
–75
1.0
TIME (µs)
1.2
1.6
1.8
2.0
–25
25
50 150
1070/71 G03
1.4
–50 0
75
100
125
2.2
JUNCTION TEMPERATURE (°C)
–75
90
DUTY CYCLE (%)
91
93
94
95
–25
25
50 150
1070/71 G02
92
–50 0
75
100
125
96
Maximum Duty Cycle
Minimum Input Voltage
TEMPERATURE (°C)
–75
2.3
MINIMUM INPUT VOLTAGE (V)
2.4
2.6
2.7
2.8
–25
25
50 150
1070/71 G04
2.5
–50 0
75
100
125
2.9
SWITCH CURRENT = 5A
SWITCH CURRENT = 0A
Switch Saturation Voltage
SWITCH CURRENT (A)
0
SWITCH SATURATION VOLTAGE (V)
0.8
1.2
8
1070/71 G05
0.4
0
1.0
25°C
1.4
0.6
0.2
2
4
6
1
3
5
7
1.6
FOR LT1071, DIVIDE
CURRENT BY 2
100°C
–55°C
150°C
Isolated Mode Flyback
Reference Voltage
TEMPERATURE (°C)
–75
FLYBACK VOLTAGE (V)
19
20
21
125
1070/71 G06
18
17
15
–25 25 7550 1500 50 100
16
23
22
R
FEEDBACK
= 500
R
FEEDBACK
= 1k
R
FEEDBACK
= 10k
Line Regulation
Feedback Bias Current
vs Temperature
INPUT VOLTAGE (V)
0
–5
REFERENCE VOLTAGE CHANGE (mV)
–3
–1
1
10
20
30 40
1070/71 G07
50
3
5
–4
–2
0
2
4
60
T
J
= 150°C
T
J
= 25°C
T
J
= –55°C
TEMPERATURE (°C)
–75
FEEDBACK BIAS CURRENT (nA)
600
500
400
300
200
100
0
125
1070/71 G09
–25 25 7550 1500 50 100
800
700
Reference Voltage
vs Temperature
TEMPERATURE (°C)
–75
REFERENCE VOLTAGE (V)
SWITCHING FREQUENCY (kHz)
1.246
1.244
1.242
1.240
1.238
1.236
1.234
125
1070/71 G08
–25 25 7550 1500 50 100
1.250
1.248
40
39
38
37
36
35
34
42
41
SWITCHING
FREQUENCY
REFERENCE
V0LTAGE
5
LT1070/LT1071
TYPICAL PERFORMANCE CHARACTERISTICS
UW
Supply Current vs Supply Voltage
(Shutdown Mode)Driver Current* vs Switch Current
SWITCH CURRENT (A)
0
DRIVER CURRENT (mA)
160
140
120
100
80
60
40
20
0
4
1070/71 G10
1
*
23 5
T
J
25°C
AVERAGE LT1070 POWER SUPPLY CURRENT IS
FOUND BY MULTIPLYING DRIVER CURRENT BY
DUTY CYCLE, THEN ADDING QUIESCENT CURRENT
T
J
= –55°C
SUPPLY VOLTAGE (V)
0
SUPPLY CURRENT (µA)
60
80
100
30
50
1070/71 G12
40
20
0
10 20 40
120
140
160
60
T
J
= 25°C
V
C
= 50mV
V
C
= 0V
Supply Current vs Input Voltage*
INPUT VOLTAGE (V)
0
6
INPUT CURRENT (mA)
8
10
12
10
20
30
*
40
1070/71 G11
50
14
UNDER VERY LOW OUTPUT CURRENT
CONDITIONS, DUTY CYCLE FOR MOST
CIRCUITS WILL APPROACH 10% OR LESS
16
7
9
11
13
15
60
T
J
= 25°C
I
SWITCH
10mA
90% DUTY CYCLE
50% DUTY CYCLE
0% DUTY CYCLE
10% DUTY CYCLE
Feedback Pin Clamp Voltage
Shutdown Thresholds
TEMPERATURE (°C)
–75
V
C
PIN VOLTAGE (mV)
V
C
PIN CURRENT (µA)
300
250
200
150
100
50
0
125
1070/71 G16
–25 25 7550 1500 50 100
400
350
300
250
200
150
100
–50
0
400
350
V
C
VOLTAGE IS REDUCED UNTIL
REGULATOR CURRENT DROPS 
BELOW 300µA
VOLTAGE
CURRENT
(OUT OF V
C
PIN)
FEEDBACK CURRENT (mA)
0
FEEDBACK VOLTAGE (mV)
300
400
500
0.8
1070/71 G18
200
100
250
350
450
150
50
0
0.2
0.4
0.6
0.1 0.9
0.3
0.5
0.7
1.0
–55°C
25°C
150°C
TEMPERATURE (°C)
–75
IDLE SUPPLY CURRENT (mA)
7
9
11
125
1070/71 G14
5
3
6
8
10
4
2
1
–25
25
75
50 150
0
50
100
V
C
= 0.6V
V
SUPPLY
= 60V
V
SUPPLY
= 3V
Idle Supply Current
vs Temperature
Normal/Flyback Mode Threshold
on Feedback Pin
TEMPERATURE (°C)
–50
400
FEEDBACK PIN VOLTAGE (mV)
FEEDBACK PIN CURRENT (µA)
410
430
440
450
500
470
0
50
75
1070/71 G13
420
480
490
460
–4
–6
–10
–12
–14
–24
–18
–8
–20
–22
–16
–25 25
100
125
150
FEEDBACK PIN VOLTAGE
(AT THRESHOLD)
FEEDBACK PIN CURRENT
(AT THRESHOLD)
Error Amplifier Transconductance
TEMPERATURE (°C)
–75
TRANSCONDUCTANCE (µmho)
3000
4000
5000
125
1070/71 G14
2000
1000
2500
3500
4500
1500
500
0
–25
25
75
50 150
0
50
100
g
m
=
(V
C
PIN)
(FB PIN)
I
V
Shutdown Mode Supply Current
V
C
PIN VOLTAGE (mV)
0
SUPPLY CURRENT (µA)
120
160
200
80
1070/71 G14
80
40
100
140
180
60
20
0
20
40
60
10 90
30
50
70
100
T
J
= 150°C
–55°C T
J
125°C
6
LT1070/LT1071
TYPICAL PERFORMANCE CHARACTERISTICS
UW
voltage is obtained by using the output of a voltage
sensing error amplifier to set current trip level. This
technique has several advantages. First, it has immediate
response to input voltage variations, unlike ordinary
switchers which have notoriously poor line transient
response. Second, it reduces the 90° phase shift at
The LT1070/LT1071 is a current mode switcher. This
means that switch duty cycle is directly controlled by
switch current rather than by output voltage. Referring to
the Block Diagram, the switch is turned “on” at the start
of each oscillator cycle. It is turned “off” when switch
current reaches a predetermined level. Control of output
OPERATION
U
Switch “Off” Characteristics
SWITCH VOLTAGE (V)
0
SWITCH CURRENT (µA)
600
800
1000
80
1070/71 G19
400
200
500
700
900
300
100
0
20
40
60
10 90
30
50
70
100
V
SUPPLY
=
3V 15V 40V 55V
FREQUENCY (Hz)
1000
TRANSCONDUCTANCE (µmho)
PHASE (°)
3000
4000
6000
7000
1k 100k 1M 10M
1070/71 G21
1000
10k
5000
2000
0
150
90
θ
60
0
–30
210
30
120
180
g
m
Transconductance of Error
Amplifier
V
C
Pin Characteristics
V
C
PIN VOLTAGE (V)
0
400
V
C
PIN CURRENT (µA)
300
200
100
300
100
0.5
1.0
200
0
1.5
2.0
2.5
1070/71 G20
V
FB
= 1.5V
(CURRENT INTO 
V
C
PIN)
V
FB
= 0.8V
(CURRENT OUT OF V
C
PIN)
T
J
= 25°C
BLOCK DIAGRAM
W
+
+
ERROR
AMP
CURRENT
AMP
0.02
(0.04 LT1071)
SHUTDOWN
CIRCUIT
MODE
SELECT
40kHz
OSC
LOGIC DRIVER
ANTISAT
16V
5A, 75V
SWITCH
V
IN
FB
V
C
COMP
GAIN 6
0.15V
1070/71 BD
1.24V
REF
2.3V
REG
FLYBACK
ERROR
AMP
SWITCH
OUT
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