SP6648 Datasheet, PDF (3/16 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: 7/19/04
SP6648 Ultra-low Quiescent Current, High Efficiency Boost Regulator
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© Copyright 2004 Sipex Corporation