SP6641BEK-L-5-0-TR Datasheet, PDF (3/14 Pages) Exar Corporation – 500mA Alkaline DC/DC Boost Regulator in SOT-23

PIN DESCRIPTION
PIN NO.
1
PIN NAME
LX
2
GND
3
V_OUT
4
SHDN
5
V_BATT
DESCRIPTION
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 through the GND
pin.
Ground pin. The internal regulator bias currents and the inductor
charging current flows out of this pin.
Output voltage sense pin, internal regulator voltage supply, and
minimum off-time one shot input. Kelvin connect this pin to the positive
terminal of the output capacitor, but for SP6641B, use 10Ω series
resistor and 1µF bypass per Figure 1 schematic.
Shutdown. Tie this pin to V_BATT for normal operation. Tie this pin the
ground to disable all circuitry inside the chip. In shutdown mode, the
output voltage will float at a diode drop below the battery potential.
Battery voltage pin. The startup circuitry runs off of this pin. The
regulating circuitry also uses this voltage to control the minimum off-
time. T_OFF ≥ K_OFF / (V_OUT – V_IN).
BLOCK DIAGRAM
V_BATT
V_BATT
V_OUT
LX
SHDN
Internal
V_BATT
V_OUT
V_BATT
SHDN
V_OUT
Min.
T_OFF
T_OFF
V_BATT
SU
EN _OSC
SUGATE
R
DRIVER
Q
CHARGE
NGATE
V_OUT
I_PK/M
LX
V_OUT
M
ITH
+
C
ICHN
-
1
REFREADY
SHDN
Ref
Block
REF
FB
+
C
-
V_OUT(LOW)
Qn
S
V_OUT
Internal
Ground
SP6641
LOAD
GND
Internal
Supply
Rev. 5/26/05, *Patent Pending
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
3
© Copyright 2002 Sipex Corporation