Typical operating characteristics (continued) – Rainbow Electronics MAX1865 User Manual
Page 6
MAX1864/MAX1865
xDSL/Cable Modem Triple/Quintuple Output
Power Supplies
6
_______________________________________________________________________________________
2
µs/div
SWITCHING WAVEFORMS
(STEP-DOWN CONVERTER)
3.35V
1.5A
C
A
MAX1864/65 toc07
1A
0
3.30V
A. V
OUT
= 3.3V (PRESET), I
OUT
= 1A, 50mV/div
B. INDUCTOR CURRENT, 500mA/div
C. V
LX
, 10V/div
V
IN
= 12V
10V
0.5A
B
1ms/div
SOFT-START
5V
4V
B
A
MAX1864/65 toc08
2V
0
0
A. V
L
, 5V/div
B. V
OUT
= 3.3V (PRESET), 2V/div
C. INDUCTOR CURRENT, 1A/div
V
IN
= 0 TO 12V
0
1A
C
0
5
10
15
20
25
30
35
40
0
2
4
6
8
10
POSITIVE LINEAR REGULATOR BASE-
DRIVE CURRENT vs. BASE-DRIVE VOLTAGE
MAX1864/65 toc09
BASE VOLTAGE (V)
BASE-DRIVE SINK CURRENT (mA)
V
FB_
= 1.0V
V
FB_
= 0.96V
REF
B2, B3 AND B4
(MAX1865) ONLY
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V
IN
= 12V, V
OUT
= 3.3V, T
A
= +25°C, unless otherwise noted.)
4.95
4.97
4.99
5.01
5.03
5.05
0
1.0
0.5
1.5
2.0
2.5
3.0
OUPUT VOLTAGE vs. LOAD CURRENT
(ADJUSTABLE MODE)
MAX1864/65 toc04
LOAD CURRENT (mA)
OUTPUT VOLTAGE (V)
4.95
4.97
4.99
5.01
5.03
5.05
0
10
5
15
20
25
30
INTERNAL 5V LINEAR REGULATOR
vs. LOAD CURRENT
MAX1864/65 toc05
LOAD CURRENT (mA)
VL (V)
1ms/div
LOAD TRANSIENT
(STEP-DOWN CONVERTER)
3.5V
3.1V
B
A
MAX1864/65 toc06
1A
0
3.3V
A. V
OUT
= 3.3V (PRESET), 200mV/div
B. I
OUT
= 10mA TO 1A, 500mA/div
V
IN
= 12V