Datasheet

SWITCH CURRENT LIMIT
(A)
1.1 1.7 2.3 2.8 3.4 4.0
SHDN PIN VOLTAGE (V)
1.2
1.0
0.9
0.7
0.6
0.4
LM2841, LM2842
SNVS540H –MARCH 2009–REVISED APRIL 2013 www.ti.com
Typical Performance Characteristics (continued)
Switch Current Limit vs. SHDN Pin Voltage
(Soft-start Implementation, LM2842) SHDN Pin Current vs. SHDN Pin Voltage
Figure 8. Figure 9.
Switching Node and Output Voltage Waveforms Load Transient Waveforms
V
IN
= 12V, V
OUT
= 3.3V, I
OUT
= 200 mA V
IN
= 12V, V
OUT
= 3.3V, I
OUT
= 300 mA to 200 mA to 300 mA
Top trace: V
OUT
, 10 mV/div, AC Coupled Top trace: V
OUT
, 20 mV/div, AC Coupled
Bottom trace: SW, 5V/div, DC Coupled Bottom trace: I
OUT
, 100 mA/div, DC Coupled
T = 1 µs/div T = 200 µs/div
Figure 10. Figure 11.
Start-up Waveform
V
IN
= 12V, V
OUT
= 3.3V, I
OUT
= 50 mA
Top trace: V
OUT
, 1V/div, DC Coupled
Bottom trace: SHDN, 2V/div, DC Coupled
T = 40 µs/div
Figure 12.
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