3A, Low-Voltage, Step-Down Regulator with
Synchronous Rectification and Internal Switches
MAX1623
__________________________________________Typical Operating Characteristics
(Circuit of Figure 2, T
A
= +25°C, unless otherwise noted.)
SWITCH OFF-TIME vs.
OFF-TIME RESISTANCE
MAX1623 TOC01
MAX1623 TOC02
EFFICIENCY
vs. OUTPUT CURRENT
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0.001
0.01
0.1
1
10
0
0
1
V
OUT
= 3.3V, R
TOFF
= 110kΩ
t
OFF
(µs)
V
OUT
= 2.5V, R
TOFF
= 180kΩ
V
OUT
= 1.1V, R
TOFF
= 280kΩ
3
5
SUPPLY CURRENT
vs. INPUT VOLTAGE
MAX1623 TOC03
1000
4
100
SUPPLY CURRENT (µA)
SHDN = IN
10
2
1
SHDN = GND
0.1
0.01
100
200
300
R
TOFF
(kΩ)
400
500
600
0
1
2
3
4
5
6
INPUT VOLTAGE (V)
OUTPUT CURRENT (A)
SWITCHING FREQUENCY
vs. LOAD CURRENT
MAX1623 TOC04
SWITCHING FREQUENCY
vs. INPUT VOLTAGE
350
SWITCHING FREQUENCY (kHz)
300
250
200
150
100
50
V
IN
= 5V, V
OUT
= 3.3V,
R
TOFF
= 110kΩ
V
IN
= 5V, V
OUT
= 2.5V,
R
TOFF
= 180kΩ
MAX1623 TOC05
350
300
SWITCHING FREQUENCY (kHz)
V
OUT
= 1.1V, R
TOFF
= 280kΩ
400
250
V
OUT
= 2.5V, R
TOFF
= 180kΩ
200
150
100
50
0
V
OUT
= 3.3V, R
TOFF
= 110kΩ
0
500
1000
1500
2000
2500
3000
0
4.5
4.7
4.9
5.1
5.3
5.5
LOAD CURRENT (mA)
INPUT VOLTAGE (V)
REFERENCE LOAD REGULATION ERROR
vs. REFERENCE LOAD CURRENT
MAX1623 TOC06
LOAD REGULATION ERROR
vs. LOAD CURRENT
-0.05
LOAD REGULATION ERROR (%)
-0.10
-0.15
-0.20
-0.25
-0.30
-0.35
-0.40
-0.45
V
OUT
= 2.5V, R
TOFF
= 180kΩ
V
OUT
= 3.3V, R
TOFF
= 110kΩ
MAX1623 TOC07
0
REFERENCE LOAD REGULATION ERROR (%)
-0.01
-0.02
-0.03
T
A
= -40°C
-0.04
T
A
= +85°C
-0.05
-0.06
0
5
10
15
20
T
A
= +25°C
0
25
-0.50
0.001
0.01
0.1
LOAD CURRENT (A)
1
10
REFERENCE LOAD CURRENT (µA)
4
_______________________________________________________________________________________
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
