Quick-PWM Slave Controllers for
Multiphase, Step-Down Supplies
MAX1887/MAX1897
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V+ = 12V, V
CC
= V
DD
= 5V, V
OUT
= 1.3V (ZMODE = GND) and 1V (ZMODE = V
CC
),
SHDN
= V
CC
(MAX1897))
DYNAMIC OUTPUT VOLTAGE TRANSITION
MAX1887 toc18
STARTUP WAVEFORM
(NO LOAD)
MAX1887 toc19
5.0V
0
1.3V
1.1V
A
5V/div
B
200mV/div
5V
0
1V
0
A
5V/div
B
1.0V/div
0
0
C
10A/div
D
10A/div
0
C
10A/div
D
10A/div
100µs/div
A. MASTER SHUTDOWN, V
SHDN
= 0 TO 5V
B. OUTPUT VOLTAGE, V
OUT
= 1.290V (NO LOAD)
C. SLAVE INDUCTOR CURRENT
D. MASTER INDUCTOR CURRENT
0
40µs/div
A. ZMODE = 0 TO 5V
B. OUTPUT VOLTAGE, V
OUT
= 1.30V (ZMODE = GND)
OR 1.10V (ZMODE = V
CC
)
C. SLAVE INDUCTOR CURRENT
D. MASTER INDUCTOR CURRENT
SHUTDOWN WAVEFORM
MAX1887 toc20
STARTUP WAVEFORM
(20A LOAD)
MAX1887 toc21
5V
0
1V
0
0
0
A
5V/div
B
1.0V/div
5V
0
A
5V/div
0
B
1.0V/div
C
10A/div
C
10A/div
D
10A/div
0
0
100µs/div
A. MASTER SHUTDOWN, V
SHDN
= 0 TO 5V
B. OUTPUT VOLTAGE, V
OUT
= 1.290V (NO LOAD)
C. SLAVE INDUCTOR CURRENT
D. MASTER INDUCTOR CURRENT
R
OUT
= 65mΩ (I
OUT
= 20A)
D
10A/div
100µs/div
A. MASTER SHUTDOWN, V
SHDN
= 5V TO 0
B. OUTPUT VOLTAGE, V
OUT
= 1.290V (NO LOAD)
C. SLAVE INDUCTOR CURRENT
D. MASTER INDUCTOR CURRENT
_______________________________________________________________________________________
9
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
