Low-Noise, 14V Input, 1A, PWM
Step-Down Converters
MAX1684/MAX1685
Typical Operating Characteristics (continued)
(Circuit of Figure 1, T
A
= +25°C, unless otherwise noted.)
MAX1684/85-11
MAXIMUM LOAD CURRENT
vs. INPUT VOLTAGE
MAX1684/85-10
SAFE OPERATING AREA
1,400
1,200
LOAD CURRENT (mA)
1,000
DROPOUT VOLTAGE (mV)
300
V
OUT
= 3.3V
200
V
OUT
= 5V
100
INDUCTOR RESISTANCE INCLUDED
0
0
200
400
600
800
1,000
LOAD CURRENT (mA)
800
600
400
200
V
OUT
= 3.3V
DROPOUT VOLTAGE vs. LOAD CURRENT
MAX1684/85-12
1.8
1.7
1.6
LOAD CURRENT (A)
1.5
1.4
1.3
1.2
1.1
PWM OR NORMAL MODE
1.0
0
2
4
6
8
10
12
400
0
0
14
2
4
6
8
10
12
14
16
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
NO-LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE (V
OUT
= 3.3V)
MAX1684/85-13
MAX1684/85-14
250
SUPPLY CURRENT (µA)
200
150
100
50
0
4
5
6
7
8
SCHOTTKY LEAKAGE
CURRENT INCLUDED
14
13
INPUT VOLTAGE (V)
12
11
10
9
8
7
6
MAX1684
MAX1685
4.5
SUPPLY CURRENT (mA)
4.0
3.5
3.0
2.5
2.0
4
5
6
7
8
9
10
11
NORMAL MODE
LOW-POWER MODE
9 10 11 12 13 14 15
2.7
12
0
2
4
6
8
10
12
14
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
INPUT VOLTAGE (V)
LOAD-TRANSIENT RESPONSE
MAX1684/85-16
SWITCHING WAVEFORM
MAX1684/85-17
SWITCHING WAVEFORM
MAX1684/85-18
I
LOAD
500mA/div
V
OUT
20mV/div
V
LX
5V/div
V
OUT
50mV/div
I
LX
100mA/div
I
LX
100mA/div
2ms/div
MAX1684, I
LOAD
= 0.1mA TO 1A, V
OUT
= 3.3V, V
IN
= 5V,
SYNC/PWM = 3.3V
1µs/div
MAX1684, I
LOAD
= 100mA, V
OUT
= 3.3V, V
IN
= 5V,
SYNC/PWM = 3.3V
1µs/div
MAX1684, I
LOAD
= 100mA, V
OUT
= 3.3V, V
IN
= 5V,
SYNC/PWM = 3.3V
6
_______________________________________________________________________________________
M AX1684/85-15
300
MAX1684
NO-LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE
(V
OUT
= 3.3V, PWM MODE)
5.0
15
PWM FIXED-FREQUENCY
OPERATION AREA
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
