LM2596
Typical Performance Characteristics
Continuous Mode Switching Waveforms
V
IN
= 20V, V
OUT
= 5V, I
LOAD
= 2A
L = 32 µH, C
OUT
= 220 µF, C
OUT
ESR = 50 mΩ
Discontinuous Mode Switching Waveforms
V
IN
= 20V, V
OUT
= 5V, I
LOAD
= 500 mA
L = 10 µH, C
OUT
= 330 µF, C
OUT
ESR = 45 mΩ
01258317
01258318
Horizontal Time Base: 2 µs/div.
A: Output Pin Voltage, 10V/div.
B: Inductor Current 1A/div.
C: Output Ripple Voltage, 50 mV/div.
Horizontal Time Base: 2 µs/div.
A: Output Pin Voltage, 10V/div.
B: Inductor Current 0.5A/div.
C: Output Ripple Voltage, 100 mV/div.
Load Transient Response for Continuous Mode
V
IN
= 20V, V
OUT
= 5V, I
LOAD
= 500 mA to 2A
L = 32 µH, C
OUT
= 220 µF, C
OUT
ESR = 50 mΩ
Load Transient Response for Discontinuous Mode
V
IN
= 20V, V
OUT
= 5V, I
LOAD
= 500 mA to 2A
L = 10 µH, C
OUT
= 330 µF, C
OUT
ESR = 45 mΩ
01258320
Horizontal Time Base: 200 µs/div.
01258319
Horizontal Time Base: 100 µs/div.
A: Output Voltage, 100 mV/div. (AC)
B: 500 mA to 2A Load Pulse
A: Output Voltage, 100 mV/div. (AC)
B: 500 mA to 2A Load Pulse
Test Circuit and Layout Guidelines
Fixed Output Voltage Versions
01258322
C
IN
C
OUT
D1
L1
— 470 µF, 50V, Aluminum Electrolytic Nichicon “PL Series”
— 220 µF, 25V Aluminum Electrolytic, Nichicon “PL Series”
— 5A, 40V Schottky Rectifier, 1N5825
— 68 µH, L38
www.national.com
8
NSC [ NATIONAL SEMICONDUCTOR ]
