Manual

MAX1684/MAX1685
Low-Noise, 14V Input, 1A, PWM
Step-Down Converters
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(Circuit of Figure 1, T
A
= +25°C, unless otherwise noted.)
1.0
1.2
1.1
1.4
1.3
1.7
1.6
1.5
1.8
04268101214
MAXIMUM LOAD CURRENT
vs. INPUT VOLTAGE
MAX1684/85 toc10
INPUT VOLTAGE (V)
LOAD CURRENT (A)
PWM OR NORMAL MODE
0
200
600
400
1000
1200
800
1400
062 8 10 12 14 16
SAFE OPERATING AREA
MAX1684/85 toc11
INPUT VOLTAGE (V)
LOAD CURRENT (mA)
V
OUT
= 3.3V
4
0
100
300
200
400
0 200 400 600 800 1000
DROPOUT VOLTAGE vs. LOAD CURRENT
MAX1684/85 toc12
LOAD CURRENT (mA)
DROPOUT VOLTAGE (mV)
V
OUT
= 3.3V
V
OUT
= 5V
INDUCTOR RESISTANCE INCLUDED
20
40
80
60
100
120
486101214
NO-LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE
MAX1684/85 toc13
INPUT VOLTAGE (V)
SUPPLY CURRENT (µA)
NORMAL MODE
LOW-POWER MODE
I
LOAD
500mA/div
V
OUT
50mV/div
2ms/div
LOAD-TRANSIENT RESPONSE
MAX1684/85 toc16
MAX1684, I
LOAD
= 0.1mA TO 1A, V
OUT
= 3.3V, V
IN
= 5V,
SYNC/PWM = 3.3V
2.0
2.5
3.0
3.5
4.0
4.5
5.0
465 7 8 9 10 11 12
MAX1684
NO-LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE
(V
OUT
= 3.3V, PWM MODE)
MAX1684/85 toc14
INPUT VOLTAGE (V)
SUPPLY CURRENT (mA)
2.7
8
7
6
10
9
14
13
12
11
15
02468101214
PWM FIXED-FREQUENCY
OPERATION AREA
M AX1684/85 toc15
OUTPUT VOLTAGE (V)
INPUT VOLTAGE (V)
MAX1685
MAX1684
V
OUT
20mV/div
I
LX
100mA/div
1µs/div
SWITCHING WAVEFORM
MAX1684/85 toc17
MAX1684, I
LOAD
= 100mA, V
OUT
= 3.3V, V
IN
= 5V,
SYNC/PWM = 3.3V
V
LX
5V/div
I
LX
100mA/div
1µs/div
SWITCHING WAVEFORM
MAX1684/85 toc18
MAX1684, I
LOAD
= 100mA, V
OUT
= 3.3V, V
IN
= 5V,
SYNC/PWM = 3.3V