Tracking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
Typical Operating Characteristics (continued)
(V+ = 12V, V
OUT
= 1.25V, T
A
= +25°C, unless otherwise noted.)
MAX1917
FREQUENCY vs. INPUT VOLTAGE
MAX1917 toc07
FREQUENCY vs. TEMPERATURE
538
536
FREQUENCY (kHz)
534
532
530
528
526
524
I
LOAD
= 3.5A
MAX1917 toc08
SHUTDOWN CURRENT
vs. INPUT VOLTAGE
MAX1917 toc09
650
600
I
OUT
= 7A
550
FREQUENCY (kHz)
500
I
OUT
= 0.1A
450
400
350
300
1
CIRCUIT OF FIGURE 3
3
5
7
9
11
13
540
4.0
3.5
SHUTDOWN CURRENT (µA)
3.0
2.5
2.0
1.5
522
520
15
CIRCUIT OF FIGURE 3
-40
-20
0
20
40
60
80
100
1.0
1
CIRCUIT OF FIGURE 6
3
5
7
9
11
13
15
INPUT VOLTAGE (V)
TEMPERATURE (°C)
INPUT VOLTAGE (V)
SHUTDOWN CURRENT
vs. INPUT VOLTAGE
MAX1917 toc10
LOAD REGULATION WITHOUT
DROOP RESISTOR
MAX1917 toc11
LOAD REGULATION WITH
DROOP RESISTOR
1.33
1.31
OUTPUT VOLTAGE (V)
1.29
1.27
1.25
1.23
1.21
1.19
1.17
1.15
V
IN
= 2.5V
V
DDR
= 2.5V
V
IN
= 12V
V
IN
= 5V
MAX1917 toc12
2.5
2.3
SHUTDOWN CURRENT (mA)
2.1
1.9
1.7
1.5
1.3
1.1
0.9
0.7
0.5
1
3
5
7
CIRCUIT OF FIGURE 3
9
11
13
1.32
1.31
1.30
OUTPUT VOLTAGE (V)
1.29
1.28
1.27
1.26
1.25
1.24
1.23
1.22
V
DDR
= 2.5V
1.35
V
IN
= 5V
V
IN
= 12V
V
IN
= 2.5V
15
-7
-5
-3
-1
1
3
5
7
-8
-6
-4
-2
0
2
4
6
8
INPUT VOLTAGE (V)
LOAD CURRENT (A)
LOAD CURRENT (A)
TRANSIENT LOAD RESPONSE
WITHOUT DROOP RESISTOR
MAX1917 toc13
TRANSIENT LOAD RESPONSE
WITH DROOP RESISTOR
MAX1917 toc14
POWER-UP WITH V
DDR
TRACKING
MAX1917 toc15
V
OUT
1V/div
V
VTT
50mV/div
V
VTT
50mV/div
V
POK
5V/div
V
DDR
2.5V
0A
I
OUT
5A/div
I
OUT
5A/div
400µs/div
V
EN/HSD
10V/div
CIRCUIT OF FIGURE 3
20µs/div
OA
CIRCUIT OF FIGURE 3
20µs/div
_______________________________________________________________________________________
7
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
