LT1070 Datasheet, PDF (5/12 Pages) Linear Technology – 5A and 2.5A High Efficiency Switching Regulators

TYPICAL PERFORMANCE CHARACTERISTICS
LT1070/LT1071
Driver Current* vs Switch Current
160
140
120
100
80
T_J = – 55°C
60
T_J ≥ 25°C
40
20
0
0
1
2
3
4
5
SWITCH CURRENT (A)
1070/71 G10
*AVERAGE LT1070 POWER SUPPLY CURRENT IS
FOUND BY MULTIPLYING DRIVER CURRENT BY
DUTY CYCLE, THEN ADDING QUIESCENT CURRENT
Supply Current vs Input Voltage*
16
T_J = 25°C
15
90% DUTY CYCLE
14
13
I_SWITCH ≤ 10mA
12
11
50% DUTY CYCLE
10
9
10% DUTY CYCLE
8
7
0% DUTY CYCLE
6
0 10 20 30 40 50 60
INPUT VOLTAGE (V)
1070/71 G11
*UNDER VERY LOW OUTPUT CURRENT
CONDITIONS, DUTY CYCLE FOR MOST
CIRCUITS WILL APPROACH 10% OR LESS
Supply Current vs Supply Voltage
(Shutdown Mode)
160
T_J = 25°C
140
120
100
V_C = 50mV
80
60
40
20
V_C = 0V
0
0 10 20 30 40 50 60
SUPPLY VOLTAGE (V)
1070/71 G12
Normal/Flyback Mode Threshold
on Feedback Pin
500
– 24
490
– 22
480
– 20
470
– 18
FEEDBACK PIN VOLTAGE
460
(AT THRESHOLD)
– 16
450
–1 4
440
– 12
430
– 10
FEEDBACK PIN CURRENT
420
(AT THRESHOLD)
–8
410
–6
400
–4
–50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
1070/71 G13
Shutdown Thresholds
400
– 400
350
CURRENT
(OUT OF V_C PIN)
300
– 350
– 300
250
– 250
200
– 200
VOLTAGE
150
– 150
100
– 100
V_C VOLTAGE IS REDUCED UNTIL
50 _{REGULATOR CURRENT DROPS}
– 50
BELOW 300µA
0
0
– 75 – 50 – 25 0 25 50 75 100 125 150
TEMPERATURE (°C)
1070/71 G16
Shutdown Mode Supply Current
200
180
160
140
120
T_J = 150°C
100
80
60
– 55°C ≤ T_J ≤ 125°C
40
20
0
0 10 20 30 40 50 60 70 80 90 100
V_C PIN VOLTAGE (mV)
1070/71 G14
Idle Supply Current
vs Temperature
11
V_C = 0.6V
10
9
8
7
V_SUPPLY = 60V
6
V_SUPPLY = 3V
5
4
3
2
1
–75 – 50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
1070/71 G14
Error Amplifier Transconductance
5000
4500
4000
g_m
=
∆I
∆V
(V_C PIN)
(FB PIN)
3500
3000
2500
2000
1500
1000
500
0
–75 – 50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
1070/71 G14
Feedback Pin Clamp Voltage
500
450
400
– 55°C
350
300
25°C
250
150°C
200
150
100
50
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
FEEDBACK CURRENT (mA)
1070/71 G18
5