LTC1439 Linear Technology, LTC1439 Datasheet - Page 6

• Manufacturer Part Number: LTC1439
• Description: Dual High Efficiency/ Low Noise/ Synchronous Step-Down Switching Regulators
• Manufacturer: Linear Technology

LTC1438/LTC1439
TYPICAL PERFORMANCE CHARACTERISTICS
200mV/DIV
6
20mV/DIV
154
152
150
148
146
–10
10
– 5
f
V
5
O
V
– 40
– 40
OUT
ITH
Normalized Oscillator Frequency
vs Temperature
Maximum Current Sense
Threshold Voltage vs Temperature
Burst Mode Operation
I
LOAD
–15
–15
= 50mA
10
10
TEMPERATURE ( C)
TEMPERATURE ( C)
35
35
60
60
85
85
W
110
110
1438 G10
1438 G13
U
1438 G16
135
135
50mV/DIV
INDUCTOR
CURRENT
V
RUN/SS
5V/DIV
1A/DIV
OUT
1
4
3
2
0
– 40
RUN/SS Pin Current
vs Temperature
Transient Response
I
LOAD
Soft Start: Load Current vs Time
–15
= 50mA to 1A
10
TEMPERATURE ( C)
35
60
85
110
1438 G11
1438 G14
1438 G17
135
50mV/DIV
– 0.25
– 0.75
–1.50
–1.50
–1.00
–1.25
12.2
12.1
12.0
11.9
11.8
11.7
V
OUT
0
– 40
Auxiliary Regulator Load
Regulation
0
SFB1 Pin Current vs Temperature
Transient Response
I
EXTERNAL PNP: 2N2907A
LOAD
–15
= 1A to 3A
AUXILIARY LOAD CURRENT (mA)
40
10
TEMPERATURE ( C)
80
35
60
120
85
160
110
1438 G12
1438 G18
1438 G15
135
200