Typical operating characteristics (continued) – Rainbow Electronics MAX1843 User Manual
Page 5
MAX1843
2.7A, 1MHz, Low-Voltage, Step-Down Regulator with
Internal Synchronous Rectification in QFN Package
_______________________________________________________________________________________
5
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
MAX1843 toc01
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
MAX1843 toc02
R
TOFF
(k
Ω)
t
OFF
(µ
s)
LOAD-TRANSIENT RESPONSE
V
OUTPUT
50mV/div
I
L
2A/div
MAX1843 toc09
10
µs/div
0
LINE-TRANSIENT RESPONSE
V
INPUT
2V/div
V
OUTPUT
20mV/div
AC-COUPLED
MAX1843 toc10
20
µs/div
I
OUT
= 2.5A, V
OUT
= +1.5V
R
TOFF
= 100k
Ω, L = 2.2µH
0
400
200
800
600
1000
1200
0
1.0
1.5
0.5
2.0
2.5
3.0
SWITCHING FREQUENCY
vs. OUTPUT CURRENT
MAX1843 toc07
OUTPUT CURRENT (A)
FREQUENCY (kHz)
V
IN
= +5V, V
OUT
= +2.5V, L = 2.5
µH
V
IN
= +3.3V, V
OUT
= +1.5V, L = 1.5
µH
V
IN
= +5V, V
OUT
= +1.5V, L = 2.5
µH
0
0
0
0
STARTUP AND SHUTDOWN
V
SS
2V/div
MAX1843 toc08
V
SHDN
5V/div
R
OUT
= 0.5
Ω, R
TOFF
= 56k
Ω
V
IN
= +3.3V, V
OUT
= +1.5V
I
INPUT
1A/div
V
OUTPUT
1V/div
1ms/div