®
Preliminary
SP6659
1.5MHz, 600mA Synchronous Buck Regulator
FEATURES
■
94% Efficiency Possible
■
600mA Output Current at V
IN
= 3V
■
2.5V to 5.5V Input Voltage Range
■
1.5MHz constant frequency operation
■
No Schottky Diode Required
■
Output Voltages as low as 0.6V
■
Slope Compensated Current Mode
Operation for Excellent Line and Load
Transient Response
■
100 % Duty Cycle in LDO Mode
■
<1µA Shutdown Current, Quiescent
Current of 300
µA
■
Over-temperature protected
■
Offered in Low Profile TSOT-23
package
VFB
VIN
VOUT
VIN
5
4
5
4
SP6659
5 Pin TSOT-23
1
RUN
SP6659
5 Pin TSOT-23
1
RUN
2
GND
3
SW
2
GND
3
SW
Adjustable
Fixed
Now Available in Lead Free Packaging
APPLICATIONS
■
Cell Phones
■
Wireless and DSL Modems
■
DSC's
■
Portable Instruments
DESCRIPTION
The SP6659 is a 600mA synchronous buck regulator using a constant frequency, current mode
architecture. The output voltage can be programmed using an external resistor divider. The 2.5V
to 5.5V input voltage range is ideal for portable applications that use a Li-Ion battery. Switching
frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and
capacitors. The internal synchronous switch increases efficiency and eliminates the need for an
external Schottky diode. The output voltage can be programmed using an external resistor
divider. Low output voltages are easily supported with the 0.6V feedback reference voltage. The
SP6659 is available in a low profile 5 pin TSOT-23 package.
TYPICAL APPLICATION SCHEMATICS
®
®
2.2µH
V
IN
RUN
4
3
2.2µH
C2
SW
22pF
V
OUT
V
IN
4
SP6659
3
SW
V
OUT
SP6659
4.7µF
Ceramic
1
5
2
R2
V
FB
R1
GND
4.7µF
10µF
Ceramic
Ceramic
RUN
1
5
2
V
OUT
10µF
Ceramic
GND
Adjustable
Fixed
Date: 07/20/05
SP6659 1.5MHz, 600mA Synchronous Buck Regulator
© Copyright 2005 Sipex Corporation
1
ABSOLUTE MAXIMUM RATINGS
Input Supply Voltage ......................................................... -0.3V to +6V
RUN, V
FB
Voltages .................................................. -0.3V to (V
IN
+ 0.3V)
SW Voltage ............................................................ -0.3V to (V
IN
+ 0.3V)
P-Channel Switch Source Current ............................................. 800mA
N-Channel Switch Sink Current .................................................. 800mA
Peak Switch Sink and Source Current ........................................... 1.3A
Operating Temperature ................................................. -40°C to +85°C
Storage Temperature ................................................. -65°C to +150
°C
Junction Temperature (Note 1) .................................................. 125
°C
These are stress ratings only and functional operation of the device at
these ratings or any other above those indicated in the operation sections
of the specifications below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may affect reliability.
ELECTRICAL CHARACTERISTICS
Vin=Vrun=3.6V, Io=0mA, Tamb= -40ºC to +85ºC, typical values at 25ºC unless otherwise noted.
Parameter
Input Voltage Range
Input DC Supply Current
Active Mode
Shutdown Mode
Min
2.5
Typ
Max
5.5
Units
V
Conditions
300
0.1
0.5880
0.6000
0.6000
0.6000
85
-1
-0.1
1.455
1.746
0.4
0.01
1.500
1.800
400
1
0.6120
0.6135
0.6180
300
1
0.1
1.545
1.854
µA
µA
Vfb = 0.5V, Vin = Vrun
Vin = 3.6V, Vrun = ZeroV
Ta=+25ºC
Vfb (Feedback Voltage)
0.5865
0.5820
V
0ºC<Ta<+85ºC
-40ºC < Ta < +85ºC
Vfb Input Bias Current
Vfb Line Regulation
Vfb Load Regulation
Regulated Output Voltage
nA
%/V
%/mA
V
V
V
Vfb = 1.0V
Vin = 2.5V to 5.5V
ILoad = 0mA to 600mA
SP6659EK1-1.5, -40ºC < Ta < +85ºC
SP6659EK1-1.8, -40ºC < Ta < +85ºC
Minimum Output Voltage
Peak inductor current
Oscillator frequency
P-channel ON resistance
N-channel ON resistance
SW Leakage Current
0.6
0.7
0.8
1.15
1.4
0.4
0.4
±0.01
0.2
1
±0.01
1.5
1.8
0.6
0.6
±1.0
1.3
±1.5
A
mHz
Ω
Ω
µA
V
Vfb = 0.5V
Closed Loop, ILoad=100mA
I
SW
= 100mA
I
SW
= -100mA
Vrun=ZeroV, Vin = 3.6V
Vsw=ZeroV, Vsw = Vin
Run Threshold Voltage
Run Leakage Current
µA
Note 1: Junction Temperature T
J
is calculated from the ambient temperature TA and ower dissipation P
D
according to the following formula: T
J
= T
A
+ P
D
X 220°C/W
PIN DESCRIPTION
PIN #
1
2
3
4
PIN NAME
RUN
GND
SW
V
IN
DESCRIPTION
Power down control pin. Forcing this pin above 1.5V enables the device. Forcing this
pin below 0.3V shuts down the device.
Ground pin.
Switching node.
Power supply pin
Adjustable Version: V
FB,
Feedback Input Pin. Connect FB to the center point of the
external resistor divider. The feedback threshold voltage is 0.6V.
5
V
FB
/ V
OUT
Fixed Output Version: V
OUT,
Output Voltage Feedback Pin. An internal resistive
divider drops the output voltage down for comparison to the internal reference voltage.
Date: 07/20/05
SP6659 1.5MHz, 600mA Synchronous Buck Regulator
© Copyright 2005 Sipex Corporation
2
TYPICAL PERFORMANCE CHARACTERISTICS
Refer to the typical application schematic, T
AMB
= +27°C
Figure 1: Fast V
IN
Startup (Scope: 50µs/div)
CH 1: Switch Node, 5V/ div
CH 2: Inductor Current, 1A/ div
CH 3:
V
OUT,
1V/ div
CH 4:
V
IN,
5V/ div
Figure 2: Load Transient 0mA to 600mA
CH 1: Output Voltage, 100mV per division AC-
Coupled
CH 2: Load Current, 500mA/ div
CH 3:
Inductor Current,
500mA/ div
Figure 3: Load Transient 50mA to 650mA
CH 1: Output Voltage, 100mV per division AC-
Coupled
CH 2: Load Current, 500mA/ div
CH 3:
Inductor Current,
500mA/ div
Figure 4: Load Transient 100mA to 700mA
CH 1: Output Voltage, 100mV per division AC-
Coupled
CH 2: Load Current, 500mA/ div
CH 3:
Inductor Current,
500mA/ div
Date: 07/20/05
SP6659 1.5MHz, 600mA Synchronous Buck Regulator
© Copyright 2005 Sipex Corporation
3
TYPICAL PERFORMANCE CHARACTERISTICS
SP6659 Efficiency vs. Load Current
V
OUT
= 1.2V
100
90
80
70
60
50
40
1
10
100
1000
Load Current (mA)
Figure 5: Efficiency Vs. Load Current, Vout =1.2V
Efficiency (%)
Vin = 2.7V
Vin = 3.3V
Vin = 4.2V
100
90
Efficiency (%)
SP6659 Efficiency vs. Load Current
V
OUT
= 1.8V
80
70
60
50
40
1
10
100
1000
Load Current (mA)
Figure 6: Efficiency Vs. Load Current, Vout =1.8V
Vin = 2.7V
Vin = 3.3V
Vin = 4.2V
Date: 07/20/05
SP6659 1.5MHz, 600mA Synchronous Buck Regulator
© Copyright 2005 Sipex Corporation
4
FUNCTIONAL DIAGRAMS
OSC
SLOPE
COMP
4
C
IN
+
-
V
IN
2.7 - 5.5V
BLANKING
+
I
SENSE
COMP
R
-
V
OUT
5
R1
0.6V
+
EA
-
+
COMP
-
Q
_
Q
RS LATCH
PWM
LOGIC
DRV
_
S
_
R
SW
3
NON-
OVERLAP
CONTROL
V
OUT
0.65V
+
OV
DET
-
+
Izero
COMP
-
0.6V
R2
V
IN
C
OUT
2
RUN
1
REF
GND
SHUTDOWN
Fixed Output Version
OSC
SLOPE
COMP
4
BLANKING
I
SENSE
COMP
+
R
C
IN
+
-
V
IN
2.7 - 5.5V
-
V
FB
5
0.6V
+
EA
-
+
COMP
-
+
OV
DET
-
Q
_
Q
RS LATCH
_
S
_
R
PWM
LOGIC
SW
3
R1
C
OUT
NON-
OVERLAP
CONTROL
DRV
V
OUT
C
2
0.65V
V
IN
RUN
1
REF
+
Izero
COMP
-
0.6V
SHUTDOWN
R2
2
GND
Adjustable Output Version
Date: 07/20/05
SP6659 1.5MHz, 600mA Synchronous Buck Regulator
© Copyright 2005 Sipex Corporation
5
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