SP7682 EXAR [Exar Corporation], SP7682 Datasheet - Page 17

• Manufacturer Part Number: SP7682
• Description: Backlight and Flash Driver in QFN 3mm x 3mm
• Manufacturer: EXAR [Exar Corporation]

Table 1: SP7682/SP7682A Capacitor Selection
Manufacturers/ Website
Murata/www.murata.com
Murata/www.murata.com
Murata/www.murata.com
Murata/www.murata.com
Ceramic Capacitor Materials
Capacitors with large output values are typically
composed of X7R, X5R, Z5U, or Y5V dielectric
materials,
recommended since they have a large change in
value
capacitors are recommended since they are
relatively low in cost and their output value
changes with temperature are relatively small.
Capacitor Selection
Careful selection of the four external capacitors
C
they will affect turn-on time, output ripple, and
transient performance. Optimum performance
will be obtained when low equivalent series
resistance (ESR) ceramic capacitors are used.
In general, low ESR may be defined as less than
100mΩ. A value of 4.7μF for the input and 2.2μF
for the output capacitor is sufficient for most
applications. The flying capacitors C1 and C2
Sept 27-07 rev G
TDK/www.tdk.com
TDK/www.tdk.com
TDK/www.tdk.com
TDK/www.tdk.com
IN
, C1, C2, and C
with
but
temperature.
Z5U
OUT
and
GRM155R60J474KE19
GRM155R60J105KE19
GRM185R60J225KE26
GRM188R60J475KE19
is important because
C1005X5R0J474K
C1005X5R0J105K
C1608X5R0J225K
C1608X5R0J475K
X5R
Part Number
Y5V
SP7682: Backlight and Flash Driver
and
are
X7R
Page 17
not
Capacitance/
0.47uF/6.3V
0.47uF/6.3V
2.2uF/6.3V
4.7uF/6.3V
2.2uF/6.3V
4.7uF/6.3V
1uF/6.3V
1uF/6.3V
Voltage
can be 1μF for most applications for backlight
and Flash, and for light output currents flying
capacitors
applications when the 4 backlight LED drivers
are drive 20mA or more and the Flash driver is
driven to 100mA or more, it is advisable to use a
4.7μF input capacitor in order to reduce the input
ripple as seen by the battery. If the LED current-
sinks are only programmed for low current
levels, or if the application is not very noise
sensitive, then a 2.2μF input capacitor may be
used. See table 1 for capacitor selection.
Thermal Protection
The SP7682 has a thermal protection circuit that
will shut down the internal LDO and charge
pump if the die temperature rises above the
thermal limit, and will restart when the die
temperature drops about 20°C below the
thermal limit.
Size/Type/Thickness
of
0402/X5R/0.55mm
0402/X5R/0.55mm
0402/X5R/0.55mm
0402/X5R/0.55mm
0603/X5R/0.55mm
0603/X5R/0.9mm
0603/X5R/0.9mm
0603/X5R/0.8mm
APPLICATIONS INFORMATION
0.47uF
Capacitor
FOOTPRINT: 3x3mm 16 pin QFN
can
© 2007 Exar Corporation
be
used.
100kHz
ESR at
0.05
0.03
0.03
0.02
0.05
0.03
0.03
0.02
For