sp6651a Exar Corporation, sp6651a Datasheet - Page 3

• Manufacturer Part Number: sp6651a
• Description: High Efficiency 800ma Synchronous Buck Regulator
• Manufacturer: Exar Corporation

Date: 5/25/04
Table 1. Operating Mode Definition
PIN NUMBER
GND
FB
D0
D1
D1
10
1
2
3
4
5
6
7
8
9
0
0
1
1
REF
+
DRVON
V
Ref
Block
RAMP
+
RST
Vos
-
-
FB'
REF'
UVLO
TSD
TONOVER
REF
ILIM/M
DRVON
VOLOW
-
+
VOLOW
C
D0
0
1
0
1
PIN NAME
BLON
DRVON
BLANK
BLANK = Tblank(=100ns) or Toff = Koff/Vout
GND
P
PV
V
V
D1
D0
FB
LX
OUT
GND
MIN Ton
IN
IN
SP6651A High Efficiency 800mA Synchronous Buck Regulator
BLANK
OVR_I
Shutdown. All internal circuitry is disabled and the power switches are opened.
Device enabled, falling UVLO threshold =2.70V
Device enabled, falling UVLO threshold =2.85V
Device enabled, falling UVLO threshold =3.00V
DESCRIPTION
Input voltage power pin. Inductor charging current passes through this pin.
Internal supply voltage. Control circuitry powered from this pin.
Open drain battery low output. (V
node to ground. (V
Digital mode control input. See table I for definition.
Digital mode control input. See table I for definition.
External feedback network input connection. Connect a resistor from
FB to ground and FB to V
regulates to the internal bandgap reference voltage of 0.8V.
Output voltage sense pin. Used by the timing circuit to set minimum on
and off times.
Internal ground pin. Control circuitry returns current to this pin.
Power ground pin. Synchronous rectifier current returns through this pin.
Inductor switching node. Inductor tied between this pin and the output
capacitor to create regulated output voltage.
TONOVER
Internal Supply
K
Vin
One-Shot
OFF
=100ns
T
OFF
/V
OUT
=
Min Ton
V
OUT
3
R
S
Min Ton = K
IN
-V
Q
_
Q
OVR_I
O
) above threshold, this node is open.
ON
OUT
DRVON
/( V
V
V
OUT
IN
IN
- V
to set the output voltage. This pin
OUT
300mV
-
)
DRIVER
IN
-V
+
O
UVLO
) less than 300mV pulls this
FUNCTIONAL DIAGRAM
-
+
C
PV
© Copyright 2004 Sipex Corporation
M
IN
PIN DESCRIPTION
ILIM/M
-
+
C
1
-
+
Zero_X
C
OVR_I
LX
P
BLON
GND