XZ5121 Datasheet, PDF (1/7 Pages) –

STEP-UP DC/DC CONVERTER —BACKLIGHT DRIVER
XZ5121 SERIES
■ DESCRIPTION
The XZ5121 Series is a fixed frequency, constant current step-up DC/DC converter ideal for driving
LEDs used in backlighting applications on cellular phones, PDAs and digital cameras etc. Output voltage
of up to 17.5V can be derived, and from a 3.2V input four white Led’s cab be driven in series or
alternatively, using a 2.5V input, a network of two parallel legs with three in each may be driven.
Luminance of the LED’s is controlled by changing the duty cycle of a PWM signal applied to the
CE pin.
In addition, an internal MOSFET with an Rds-on of 2Ω is used. Allow profile and small board area solution
can be achieved using a chip coil and an ultra small ceramic output capacitor (CL) of 0.22uF.
■ FEATURES
l input voltage range : 2.5V—6V
l Output voltage range : up to 17.5V externally set-up reference voltage 0.2V±5%
l Oscillation frequency : 1.0MHZ±20% :
l On resistance
: ^2.0Ω
l Efficiency
l Control
l Stand-by Current
l Load capacitor
l Lx limit Current
: 88%(When driving 3 white LEDs in series VIN=3.6V ILED=20mA)
: PWM control
: ISTB=1.0uA(MAX)
: 0.22uF,ceramic
:300mA
■ APPLICATIONS
l For White LED Drivers
l Mobil phones, PHS
l PDAs
l Digital still cameras
■ _PACKAGE
SOT23—6
■ BLOCK DIAGRAM
Figure 1
1