Document 140-1
Mag Amp Toroids – G642X Series
This product is not RoHS-compliant. Contact Coilcraft
for current status or possible alternatives.
These low cost saturable reactor (mag amp) coils are
designed to regulate switching power supplies operating
at frequencies from 20 kHz to over 100 kHz.
In multi-output circuits requiring tight crossregulation,
mag amp control is simple and more cost-effective than
adding conventional linear voltage regulators to each
output. Mag amps are also particularly advantageous
where load current exceeds 1 or 2 amps, because of
their efficiency and low heat dissipation.
Coilcraft
Designer’s Kit No. P206
contains samples of
all values shown. To order, please contact Coilcraft or
visit
http://order.coilcraft.com.
Advantages
•
•
•
•
•
Higher efficiency than linear regulators, especially at higher currents
Simple cross-regulation of multi-output supplies
Lower EMI
Frequency range of 20 kHz to over 100 kHz
Standardized construction for maximum economy
Electrical Specifications
G6421-A
Current
Volt-time product
(typical)
Weight (g)
1
G6422-A
1A
133 v-µsec
5.5
G6423-A
1A
372 v-µsec
9.6
G6424-A
5A
42 v-µsec
5.2
G6425-A
5A
66 v-µsec
6.6
G6426-A
5A
186 v-µsec
12.8
1A
93 v-µsec
4.4
1. Based on 40°C maximum temperature rise.
2. Operating temperature range –40°C to +85°C.
3. Electrical specifications at 25°C.
Specifications subject to change without notice.
Please check our website for latest information.
Document 140-1
Revised 12/03/02
© Coilcraft, Inc. 2008
Document 140-2
Mag Amp Toroids - G642X Series
Dimensions
1
A
4
2
NC
1
2
0.600 ±0.010
15,24 ±0,254
0.040 ±0.003
dia
1,02 ±0,08
+0.025
0.150
–0.010
+0,635
2
4
B
3,81
–0,254
Part
number
1
2
A max
0.85/21,59
1.00/25,40
1.25/31,75
0.90/22,86
1.05/26,67
1.30/33,02
B max
0.65/16,51
0.65/16,51
0.65/16,51
0.55/13,97
0.55/13,97
0.55/13,97
C max
0.825/20,96
0.825/20,96
1.150/29,21
0.825/20,96
0.825/20,96
1.150/29,21
0.250 ±0.010
6,35 ±0,254
4
G6421-A
G6422-A
G6423-A
G6424-A
G6425-A
G6426-A
C
Test Circuit
The test circuit below can be used to test the volt-time
product supported by each of the mag amp coils.
Apply the square wave to the coil and observe the
current waveform (voltage across the series resistor).
Increase the applied voltage until a spike appears at the
end of each half cycle, indicating core saturation.
Saturation is defined as the point at which the magni-
tude of the spike has become twice the peak value of
the square wave. (Actually the current square wave is
not flat but gradually increases due to the magnetizing
current.)
To record the volt-time product, multiply the applied
peak voltage by the time required to reach saturation
and divide by two.
The series resistor should be as small as possible,
without loading the square wave supply. If the square
wave generator is powerful enough, the differential amp
may not be necessary.
+
+
+
Vr
(Scope)
t
0
2v
t
Square Wave
Generator
Differential
Amplifier
V Applied
–
Inductor
under
test
V Applied
0
v
RS
Scope
–
–
Specifications subject to change without notice.
Please check our website for latest information.
Document 140-2
Revised 12/03/02
© Coilcraft, Inc. 2008
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