MAX1996AETI+ Maxim Integrated Products, MAX1996AETI+ Datasheet - Page 22

• Manufacturer Part Number: MAX1996AETI+
• Description: Display Drivers CCFL Backlight Controller
• Manufacturer: Maxim Integrated Products

Specifications of MAX1996AETI+

• Lead Free Status / Rohs Status: Details

High-Efficiency, Wide Brightness
Range, CCFL Backlight Controller
Table 5. Components for the Dual-Lamp Application Circuit
Figure 13. Layout Example
Table 6. CCFL Specifications
2) Utilize a star ground configuration for power and
3) Route high-speed switching nodes away from sensi-
22
CCFL Minimum Strike Voltage
(Kick-Off Voltage)
CCFL Typical Operating
Voltage (Lamp Voltage)
CCFL Maximum Operating
Current (Lamp Current)
CCFL Maximum Frequency
(Lamp Frequency)
NOTE: DUAL MOSFET N2 IS MOUNTED ON THE BOTTOM SIDE OF THE PC BOARD DIRECTLY UNDER N1.
DESIGNATION
analog grounds. The power ground and analog
ground should be completely isolated—meeting
only at the center of the star. The center should be
placed at the backside contact to the QFN pack-
age. Using separate copper planes for these
planes may simplify this task. Quiet analog ground
is used for REF, CCV, CCI, RX, and MINDAC (if a
resistive voltage-divider is used).
tive analog areas (IFB, VFB, REF, ILIM). Make all pin-
strap control input connections (ILIM, etc.) to analog
ground or V
______________________________________________________________________________________
T1, T2
N1
SPECIFICATION
R5
R7
N2
CC
, rather than power ground or V
HIGH-CURRENT PRIMARY CONNECTION
C2
1kΩ ±5% resistor
20kΩ ±5% resistor
1:100 transformers
DESCRIPTION
SYMBOL
V
V
I
f
L
L
S
L
mA
UNITS
V
V
kHz
RMS
RMS
RMS
DD
.
Although CCFLs typically operate at <550V
(up to 1000V
strike voltage is typically higher at cold temperatures and at the end of
the life of the tube.
Once a CCFL has been struck, the voltage is required to maintain light
output falls to approximately 550V
as little as 250V
constant, even as the tube’s brightness is varied.
The maximum AC current through a CCFL is typically 5mA
current is not allowed through CCFLs. The maximum lamp current is
set by sense resistor R1 and the maximum brightness setting.
R1 = 2.2
The maximum AC lamp-current frequency. The MAX1996A is designed
to operate between 20kHz and 300kHz.
—
—
T912MG-1018
RECOMMENDED DEVICE
✕
4) Mount the decoupling capacitor from V
5) The current-sense paths for LX1 and LX2 to GND
6) Ensure the feedback connections are short and
V
IFBMAX
RMS
as close as possible to the IC with dedicated traces
that are not shared with other signal paths.
must be made using Kelvin-sense connections to
guarantee the current-limit accuracy. With 8-pin SO
MOSFETs, this is best done by routing power to the
MOSFETs from outside using the top copper layer,
while connecting GND and LX inside (underneath)
the 8-pin SO package.
direct. To the extent possible, IFB and V
RMS
T1
and beyond) is required initially to start the tube. The
/I
. The operating voltage of the CCFL stays relatively
LMAX
.
DESCRIPTION
RMS
HIGH-VOLTAGE SECONDARY CONNECTION
. Shorter tubes may operate on
C3
RMS
—
—
Toko
www.tokoam.com
R2
C4
, a higher voltage
MANUFACTURER
D1
RMS
CC
FB
LAMP
. DC
connec-
to GND