Rainbow Electronics MAX1842 - Manual (Page 6)

MAX1742/MAX1842
1A/2.7A, 1MHz, Step-Down Regulators with
Synchronous Rectification and Internal Switches
6 _______________________________________________________________________________________
0V
0V
0V
0A
MAX1742
STARTUP AND SHUTDOWN
I INPUT
1A/div
V OUTPUT
1V/div
V SS
2V/div
MAX1742 toc06
1ms/div
V SHDN
5V/div
0V
MAX1742
LOAD-TRANSIENT RESPONSE
V OUTPUT
AC-COUPLED,
50mV/div
I
L
0.5A/div
MAX1742 toc07
10 µs/div
0V
MAX1742
LINE-TRANSIENT RESPONSE
V INPUT
2V/div
V OUTPUT
20mV/div
AC-COUPLED
MAX1742 toc08
20 µs/div
I OUT = 1A, V OUT = 1.5V, R TOFF = 100k Ω, L = 6µH
0
150
100
50
200
250
300
350
400
450
500
0
30
20
10
40
50
60
70
80
90
100
0 2 1 3 4 5 6
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX1742 toc09
V IN (V)
NO-LOAD SUPPLY CURRENT, I
IN
+ I
CC
(µ
A)
SHUTDOWN SUPPLY CURRENT, I
IN
+ I
CC
(nA)
NO LOAD
SHUTDOWN
Typical Operating Characteristics (continued)
(Circuit of Figure 1, T A = +25°C, unless otherwise noted.)
0
1.0
0.5
2.0
1.5
3.0
2.5
3.5
4.5
4.0
5.0
0 100 150 200 50 250 300 350 450 400 500
OFF-TIME vs. R TOFF
MAX1742 toc10
R TOFF (k Ω)
t OFF
(µ
s)