DS3994 Maxim Integrated Products, DS3994 Datasheet - Page 26

• Manufacturer Part Number: DS3994
• Description: 4-Channel Cold Cathode Fluorescent Lamp Controller
• Manufacturer: Maxim Integrated Products

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DataSheet
4
4-Channel Cold-Cathode
Fluorescent Lamp Controller
Table 5. Transformer Specifications
Note 1: Primary should be Bifilar wound with center tap connection.
Note 2: Turns ratio is defined as secondary winding divided by the sum of both primary windings.
Note 3: 40:1 is the nominal turns ratio for driving a 438mm x 2.2mm lamp with a 12V supply. Refer to Application Note 3375 for more
Table 6. Resistor and Capacitor Selection Guide
26
Turns Ratio (Secondary/Primary)
Frequency
Output Power
Output Current
Primary DCR
Secondary DCR
Primary Leakage
Secondary Leakage
Primary Inductance
Secondary Inductance
Center Tap Voltage
Secondary Output Voltage
DESIGNATOR
U
.com
____________________________________________________________________
R1
R2
R3
R4
R5
R6
R7
R8
C1
C2
C3
C4
C5
information.
PARAMETER
QTY
1/Ch
1/Ch
1/Ch
1/Ch
1/Ch
1
1
1
1
1
1
1
1
12.5kΩ to
20kΩ to
18kΩ to
VALUE
105kΩ
100nF
4.7kΩ
4.7kΩ
4.7kΩ
140Ω
0.1µF
10kΩ
40kΩ
45kΩ
10pF
27nF
33µF
(Notes 1, 2, 3)
Center tap to one end
100ms minimum
Continuous
TOLERANCE
(%) AT 25°C
CONDITIONS
10
20
10
1
1
1
1
5
5
5
1
5
5
TEMPERATURE
COEFFICIENT
±1000ppm/°C
≤153ppm/°C
≤153ppm/°C
Any grade
Any grade
Any grade
Any grade
X7R
X7R
X7R
—
—
—
2000
1000
10.8
MIN
—
See the Setting the SVM Threshold Voltage section.
2% or less total tolerance. See the Lamp Frequency
Configuration section to determine value.
2% or less total tolerance. See the Lamp Frequency
Configuration section to determine value.
—
—
—
See the Setting the RMS Lamp Current section.
C ap aci tor val ue w i l l al so affect LC M b i as vol tag e d ur i ng
p ow er - up . A l ar g er cap aci tor m ay cause a l ong er ti m e
for V
2kV to 4kV breakdown voltage required.
C ap aci tor val ue w i l l al so affect LC M b i as vol tag e d ur i ng
p ow er - up . A l ar g er cap aci tor m ay cause a l ong er ti m e
for V
—
Place close to V
40
D C B
D C B
to r each i ts nor m al op er ati ng l evel .
to r each i ts nor m al op er ati ng l evel .
TYP
200
500
185
500
40
12
70
12
CC
5
and GND on DS3994.
NOTES
MAX
13.2
80
6
8
UNITS
V
kHz
mΩ
mA
mH
mH
µH
µH
RMS
W
Ω
V