Datasheet

MAX8686
Single/Multiphase, Step-Down,
DC-DC Converter Delivers Up to 25A Per Phase
_______________________________________________________________________________________ 5
SINGLE-PHASE EFFICIENCY
vs. LOAD CURRENT
MAX8686 toc01
LOAD CURRENT (A)
EFFICIENCY (%)
20155 10
77.5
80.0
82.5
85.0
90.0
87.5
92.5
95.0
75.0
025
V
OUT
= 3.3V
V
OUT
= 1.8V
V
OUT
= 2.5V
AIRFLOW = 300 LFM
SINGLE-PHASE EFFICIENCY
vs. LOAD CURRENT (V
IN
= 5V)
MAX8686 toc02
LOAD CURRENT (A)
EFFICIENCY (%)
20155 10
77.5
80.0
82.5
85.0
90.0
87.5
92.5
95.0
75.0
025
V
OUT
= 1.2V
V
OUT
= 1.8V
V
OUT
= 2.5V
CIRCUIT OF FIGURE 3
AIRFLOW = 300 LFM
EFFICIENCY vs. LOAD CURRENT
MAX8686 toc03
LOAD CURRENT (A)
EFFICIENCY (%)
17148 11
80
81
82
83
85
84
86
87
79
520
270kHz
379kHz
467kHz
564kHz
AIRFLOW = 300 LFM
SWITCHING FREQUENCY
vs. CFREQ CAPACITANCE
MAX8686 toc04
CFREQ CAPACITANCE (pF)
SWITCHING FREQUENCY (kHz)
650600500 550200 250 300 350 400 450150
300
400
500
600
700
800
900
1000
1100
1200
1300
200
100 700
CLOSED-LOOP FREQUENCY RESPONSE
(I
OUT
= 160A, 8 PHASES)
FREQUENCY (kHz)
GAIN (dB)
10 100
-40
-30
-20
-10
0
10
20
30
40
50
-50
PHASE (DEGREES)
-144
-108
-72
-36
0
36
72
108
144
180
-180
11k
MAX8686 toc05
PHASE
GAIN
OUTPUT VOLTAGE vs. OUTPUT CURRENT
MAX8686 toc06
OUTPUT CURRENT (A)
OUTPUT VOLTAGE (V)
20155 10
1.2005
1.2010
1.2015
1.2020
1.2030
1.2025
1.2035
1.2040
1.2000
025
AIRFLOW = 300 LFM
OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX8686 toc07
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
19181716151413121110987
1.20
1.25
1.30
1.15
620
I
OUT
= 10A
OUTPUT LOAD TRANSIENT
MAX8686 toc08
100μs/div
V
OUT
200mV/div
AC-COUPLED
I
OUT
42A/div
CIRCUIT OF FIGURE 4
AIRFLOW = 300 LFM
SOFT-START WITH EN CONTROL
(I
OUT
= 10A)
MAX8686 toc09
1ms/div
EN
2V/div
SS
2V/div
POK
5V/div
V
OUT
500mV/div
CIRCUIT OF FIGURE 4
Typical Operating Characteristics
(V
IN
= 12V, f
SW
= 500kHz, single phase, circuit of Figure 2, unless otherwise noted.)