ML4851CS-3 MICRO-LINEAR [Micro Linear Corporation], ML4851CS-3 Datasheet - Page 8

• Manufacturer Part Number: ML4851CS-3
• Description: Low Current, Voltage Boost Regulator
• Manufacturer: MICRO-LINEAR [Micro Linear Corporation]

ML4851
DESIGN CONSIDERATIONS
LAYOUT
Good PC board layout practices will ensure the proper
operation of the ML4851. Important layout considerations
include:
A sample PC board layout is shown in Figure 6.
ML4851-3
8
L = 10µH
L = 18µH
L = 33µH
L = 56µH
Use adequate ground and power traces or planes
Keep components as close as possible to the ML4851
Use short trace lengths from the inductor to the V
and from the output capacitor to the V
Use a single point ground for the ML4851 PWR GND
pin and the input and output capacitors, and connect
GND to PWR GND with a separate trace
V
1.0
1.5
2.0
1.0
1.5
2.0
2.5
3.0
1.0
1.5
2.0
2.5
3.0
1.0
1.5
2.0
2.5
3.0
IN
R
A
R
B
I
OUT

 
108.3
184.1
125.5
185.7
243.4
120.4
159.6
108.0
V
45.8
30.1
70.9
17.6
42.7
76.1
10.6
25.9
47.6
75.8
IN MIN
. 0 2
(mA)
(
)
Table 1. Maximum Output Current and Efficiency vs. V
1
EFFICIENCY PERCENTAGE
OUT
(Continued)
July, 2000
77.6
77.7
77.9
82.5
83.5
83.9
84.5
85.4
86.0
87.8
88.7
89.7
90.7
85.2
89.1
90.8
92.0
93.1
pin
L
pin
(6)
ML4851-5
DATASHEET
L = 10µH
L = 18µH
L = 33µH
L = 56µH
V
1.0
1.5
2.0
1.0
1.5
2.0
2.5
3.0
3.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
TOP LAYER
IN
Figure 6. Sample PC Board Layout
I
OUT
123.1
125.3
169.9
236.9
106.9
147.5
190.0
227.8
122.1
149.6
24.2
68.0
15.7
43.3
80.4
24.8
47.4
74.5
13.9
28.5
45.7
67.1
92.5
9.1
5.5
IN
(mA)
EFFICIENCY PERCENTAGE
BOTTOM LAYER
78.3
79.9
80.3
82.3
84.8
85.7
86.2
86.5
87.0
83.5
87.0
88.6
89.5
90.3
90.8
91.4
92.1
80.1
85.9
88.9
90.3
91.4
92.3
92.6
93.8