Typical operating characteristics (continued) – Rainbow Electronics MAX887 User Manual
Page 4
MAX887
100% Duty Cycle, Low-Noise,
Step-Down, PWM DC-DC Converter
4
_______________________________________________________________________________________
____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 2, T
A
= +25°C, unless otherwise noted.)
0
10
20
30
40
50
60
70
80
90
100
0.0001 0.001
0.01
0.1
0.6
EFFICIENCY (%)
OUTPUT CURRENT (A)
EFFICIENCY vs. OUTPUT CURRENT
MAX887-04
IDLE MODE
(SYNC = GND)
V
OUT
= 3.3V
V
IN
= 5V
V
IN
= 7V
V
IN
= 9V
V
IN
= 11V
V
IN
= 4V
0
10
20
30
40
50
60
70
80
90
100
0.0001
0.001
0.01
0.1
0.6
EFFICIENCY (%)
OUTPUT CURRENT (A)
EFFICIENCY vs. OUTPUT CURRENT
MAX887-05
IDLE MODE
(SYNC = GND)
V
OUT
= 5V
V
IN
= 5.5V
V
IN
= 9V
V
IN
= 7V
V
IN
= 11V
0
200
400
600
800
1000
1200
3
5
7
9
11
13
15
17
MAXIMUM OUTPUT CURRENT (mA)
SUPPLY VOLTAGE (V)
MAXIMUM OUTPUT CURRENT
vs. SUPPLY VOLTAGE
MAX887-06
GUARANTEED OUTPUT CURRENT
OF FIGURE 2 IS 600mA
3.3V SETTING, V
OUT
= 3.135V
5V SETTING, V
OUT
= 4.75V
0
200
400
600
800
1000
1200
0
100
200
300
400
500
600
MAXIMUM OUTPUT CURRENT (mA)
SYNC FREQUENCY (kHz)
MAXIMUM OUTPUT CURRENT
vs. SYNC FREQUENCY
MAX887-07
C2, C3 = 47µF
L1 = 33µH
V
IN
= 5V
V
OUT
= 3.3V
V
OUT
= -5% at I
OUT(MAX)
250
260
270
280
290
300
310
320
330
340
350
0
2
4
6
8
10
12
14
16
18
SWITCHING FREQUENCY (kHz)
SUPPLY VOLTAGE (V)
SWITCHING FREQUENCY
vs. SUPPLY VOLTAGE
MAX887-10
V
OUT
= 3.3V
0
0.5
1.5
2.5
3.5
3.0
2.0
1.0
QUIESCENT CURRENT (mA)
SUPPLY VOLTAGE (V)
QUIESCENT SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX887-08
A
A
A: V
OUT
= 3.3V, PWM MODE
B: V
OUT
= 3.3V, PFM MODE
0
2
4
6
8
10
12
14
16
18
C
B
0
0.5
1.0
1.5
2.0
2.5
3.0
-60 -40 -20 0
20 40 60 80 100 120 140
QUIESCENT CURRENT (mA)
TEMPERATURE (°C)
QUIESCENT CURRENT
vs.TEMPERATURE
MAX887-09
PWM MODE
V
IN
= 5.3V
V
OUT
= 3.3V
PFM MODE
250
260
270
280
290
300
310
320
330
340
350
FREQUENCY (kHz)
TEMPERATURE (°C)
SWITCHING FREQUENCY
vs. TEMPERATURE
MAX887-11
V
OUT
= 3.3V
-60 -40 -20
0
20 40 60 80 100 120 140
4
-1
10k
10M
OUTPUT RIPPLE AND HARMONICS
0
2
3
1
MAX887 TOC-20
FREQUENCY (Hz)
OUTPUT NOISE (mV)
100k
1M
V
IN
= 5V
V
OUT
= 3.3V
I
OUT
= 500mA
PWM MODE