Fairchild FAN53330 User Manual

FAN5330/5333A/B
Evaluation Board User Manual
1.6MHz PWM Switching Frequency
Adjustable Output Voltage
100mV Feedback Voltage (FAN5330 and
FAN333A)
300mV Feedback Voltage (FAN5333B)
Low Shutdown Current: <1uA
Cycle-by-Cycle Current Limit
1.5A Peak Switch Current
Small 5-lead SOT23 Package
Description:
The FAN53330 and FAN5333A/B Evaluation Boards are compact circuits including the
FAN5330 SX or FAN5333A/B SX in a 5-Lead SOT23 package and an external Schottky diode
which delivers stored inductor current to six of Fairchild's super bright white LEDs. The
FAN5330 and FAN5333A/B demo boards are completely assembled and tested surface mount
boards, providing easy probe access points to all inputs and outputs so that electrical
characteristics and waveforms can be easily measured.
Where To Begin:
1: Connect Vin (1.8 to 5.5V) and Gnd (0V).
2: Use jumper J1 to select "ON" and "OFF" modes.
3: Verify that the output current I
(Note: I
LED
and V = 0.3V(typical) for the FAN5333B. R = 5Ohm for the
REF
FAN5333A/FAN5330 and R = 15Ohm for the FAN5333B)
4: To verify output current at V
input voltage levels.
5: To verify supply current in "ON" and "OFF" modes, observe that in shutdown mode,
supply current will drop below 1uA at Vin.
6: Verify that V
does not exceed its maximum value.
(Note: Although the load current is indirectly limited by the maximum inductor
current, V
OUT
Schottky diode and/or the IC)
(Note: The Schottky diode D1, rectifies the voltage pulses generated by the inductor)
©2005 Fairchild Semiconductor Corporation
FAN5330/5333A/B Version 1.0
LED
= (V / R) where V
REF REF
, observe that the current remains constant for varying
OUT
is independent of V
OUT
is not allowed to be shorted to ground. Failure results in damaging the
Figure 1: FAN5330/33 SX
= .02A for all models.
= 0.1V(typical) for the FAN5333A/FAN5330
in the 1.8 to 5.5V range and the load current
IN
1
July 2005
www.fairchildsemi.com