LM1577, LM2577
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SNOS658D –JUNE 1999–REVISED APRIL 2013
Table 2. Table of Standardized Inductors and
Manufacturer's Part Numbers(1)
Inductor
Code
L47
Manufacturer's Part Number
Schott
Pulse
Renco
RL2442
RL2443
RL2444
RL1954
RL1953
RL1952
RL1951
RL1950
RL2445
RL2446
RL2447
RL1961
RL1960
RL1959
RL1958
RL2448
67126980
67126990
67127000
67127010
67127020
67127030
67127040
67127050
67127060
67127070
67127080
67127090
67127100
67127110
67127120
67127130
PE - 53112
PE - 92114
PE - 92108
PE - 53113
PE - 52626
PE - 52627
PE - 53114
PE - 52629
PE - 53115
PE - 53116
PE - 53117
PE - 53118
PE - 53119
PE - 53120
PE - 53121
PE - 53122
L68
L100
L150
L220
L330
L470
L680
H150
H220
H330
H470
H680
H1000
H1500
H2200
(1) Schott Corp., (612) 475-1173
1000 Parkers Lake Rd., Wayzata, MN 55391
Pulse Engineering, (619) 268-2400
P.O. Box 12235, San Diego, CA 92112
Renco Electronics Inc., (516) 586-5566
60 Jeffryn Blvd. East, Deer Park, NY 11729
2. Compensation Network (RC, CC) and Output Capacitor (COUT) Selection
RC and CC form a pole-zero compensation network that stabilizes the regulator. The values of RC and CC are
mainly dependant on the regulator voltage gain, ILOAD(max), L and COUT. The following procedure calculates values
for RC, CC, and COUT that ensure regulator stability. Be aware that this procedure doesn't necessarily result in RC
and CC that provide optimum compensation. In order to ensure optimum compensation, one of the standard
procedures for testing loop stability must be used, such as measuring VOUT transient response when pulsing
ILOAD (see Figure 39).
A. First, calculate the maximum value for RC.
(8)
Select a resistor less than or equal to this value, and it should also be no greater than 3 kΩ.
B. Calculate the minimum value for COUT using the following two equations.
(9)
The larger of these two values is the minimum value that ensures stability.
C. Calculate the minimum value of CC .
(10)
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