SP6648EU-L Datasheet, PDF (3/34 Pages) Sipex Corporation – Ultra-low Quiescent Current, High Efficiency Boost Regulator

PIN NUMBER
1
PIN NAME
V_BATT
2
LBI
3
LBON
4
R_LIM
5
SHDN
6
FB
7
GND
8
PGND
9
LX
10
V_OUT
PIN DESCRIPTION
DESCRIPTION
Battery Voltage. The startup circuitry is powered by this pin. Battery
Voltage is used to calculate switch off time: t_OFF = K_OFF/ (V_OUT - V_BATT).
When the battery voltage drops below 0.61V the SP6648 goes into an
undervoltage lockout mode (UVLO), where the part is shut down.
Low Battery Input. LBI below 0.61V causes the SP6648 pin to pull LBON
pin down to ground. Use a resistor divider to program the low voltage
threshold for a specific battery configuration.
Low Battery Output Not. Open drain NMOS output that sinks current to
ground when LBI is below 0.61V.
Current Limit Resistor. By connecting a resistor R_LIM from this pin to
ground the inductor peak current is set by I_PEAK=1600/R_LIM. The range for
R_LIM is 9kΩ (for 180mA) to 1.KΩ (for 1.6A).
Shutdown Not. Tie this pin high to V_BATT, for normal operation. Pull this
pin to ground to disable all circuitry inside the chip. In shutdown the
output voltage will float down to a diode drop below the battery voltage.
Feedback. Connect this pin to GND for fixed +3.3V operation. Connect
this pin to a resistor voltage divider between V_OUT and GND for
adjustable output operation.
Ground. Connect to ground plane.
Power Ground. The inductor charging current flows out of this pin.
Inductor Switching Node. Connect one terminal of the inductor to the
positive terminal of the battery. Connect the second terminal of the
inductor to this pin. The inductor charging current flows into LX, through
the internal charging N-channel FET, and out the PGND pin.
Output Voltage. The inductor current flows out of this pin during switch
off-time. It is also used as the internal regulator voltage supply. Connect
this pin to the positive terminal of the output capacitor.
Date: 6/7/06 Rev B
SP6648 Ultra-low Quiescent Current, High Efficiency Boost Regulator
3
© 2006 Sipex Corporation