User Manual

MAX746
High-Efficiency, PWM, Step-Down,
N-Channel DC-DC Controller
4 _______________________________________________________________________________________
N0-LOAD SUPPLY CURRENT
vs. SUPPLY VOLTAGE
NO-LOAD SUPPLY CURRENT (mA)
0.8
0.9
1.0
1.1
1.2
579111315
SUPPLY VOLTAGE (V)
MAX746-01
0
-75

NO-LOAD SUPPLY CURRENT 
vs. TEMPERATURE
MAX746-02
TEMPERATURE (°C)
NO-LOAD SUPPLY CURRENT (mA)
3
1
4
2
-50 -25 0 25 50 75 100 125
V+ = 9V
V
OUT
= 5V
ENTIRE
CIRCUIT
SCHOTTKY DIODE
LEAKAGE EXCLUDED
4
0
0.01
PEAK INDUCTOR CURRENT
vs. OUTPUT CURRENT
1
2
MAX746-03
OUTPUT CURRENT (A)
PEAK INDUCTOR CURRENT (A)
3
0.1 1 10
V
IN
= 12V
V
IN
= 9V
V
IN
= 6V
CIRCUIT OF FIGURE 1a
V
OUT
= 5V
1.5
0
0.01
PEAK INDUCTOR CURRENT
vs. OUTPUT CURRENT
0.5
MAX746-03
OUTPUT CURRENT (A)
PEAK INDUCTOR CURRENT (A)
1.0
0.1 1
CIRCUIT OF FIGURE 1c
V
OUT
= 5V
V
IN
= 12V
V
IN
= 6V
10
100
70
0.01

EFFICIENCY vs. OUTPUT CURRENT
80
MAX746-07
OUTPUT CURRENT (A)
EFFICIENCY (%)
90
0.1 1 10
V
IN
= 12V
V
IN
= 9V
V
IN
= 6V
CIRCUIT OF FIGURE 1a
V
OUT
= 5V
4
0
0.01
PEAK INDUCTOR CURRENT
vs. OUTPUT CURRENT
1
2
MAX746-05
OUTPUT CURRENT (A)
PEAK INDUCTOR CURRENT (A)
3
0.1 1 10
CIRCUIT OF FIGURE 1b
V
OUT
= 3.3V
V+ = 5V
100
70
0.01

EFFICIENCY vs. OUTPUT CURRENT
80
MAX746-06
OUTPUT CURRENT (A)
EFFICIENCY (%)
90
0.1 1 10
CIRCUIT OF FIGURE 1c
V
IN
= 12V
V
IN
= 6V
V
OUT
= 5V
100
70
0.01

EFFICIENCY vs. OUTPUT CURRENT
80
MAX746-08
OUTPUT CURRENT (A)
EFFICIENCY (%)
90
0.1 1 10
CIRCUIT OF FIGURE 1b
V
OUT
= 3.3V
V+ = 5V
CONTINUOUS-CONDUCTION MODE
BOUNDARY AND CORRESPONDING
PEAK INDUCTOR CURRENT
SUPPLY VOLTAGE (V)
5
7
9
11
13
0.7
OUTPUT CURRENT (A)
15
MAX746-09
0.9 1.1 1.3 1.5 1.7
DISCONTINUOUS-
CONDUCTION REGION
CONTINUOUS-
CONDUCTION
REGION
PEAK
INDUCTOR
CURRENT
__________________________________________Typical Operating Characteristics
(Circuit of Figure 1a, T
A
= +25°C, unless otherwise noted.)