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SP6134
Dual Supply Synchronous Buck Controller
FEATURES
■
■
■
■
■
■
■
■
■
■
■
■
3V to 15V Step Down Achieved Using Dual Input
Small 10-Pin MSOP Package
2A to 15A Ouput Capability
Highly Integrated Design, Minimal Components
UVLO Detects Both V
CC
and V
IN
Short Circuit Protection with Auto-Restart
On-Board 1.5Ω sink (2Ω source) NFET Drivers
Programmable Soft Start
Fast Transient Response
High Efficiency: Greater than 94% Possible
Asynchronous Start-Up into a Pre-Charged Output
U.S. Patent #6,922,041
V
CC
1
GL
2
GND
3
V
FB
4
COMP
5
10
BST
SP6134
10 Pin MSOP
9
GH
8
SWN
7
SS
6
UVIN
Now Available in Lead Free Packaging
APPLICATIONS
■
12V DPA
■
Communications Systems
■
Graphics Cards
DESCRIPTION
The SP6134 is a synchronous step-down switching regulator controller optimized for high efficiency. The part is
designed to be especially attractive for dual supply, 12V step down with 5V used to power the controller. This lower V
CC
voltage minimizes power dissipation in the part. The SP6134 is designed to drive a pair of external NFETs using a fixed
600kHz frequency, PWM voltage mode architecture. Protection features include UVLO, thermal shutdown and output
short circuit protection. The SP6134 is available in the cost and space saving 10-pin MSOP
.
TYPICAL APPLICATION CIRCUIT
VIN
3.5V - 15V
C1
22µF
16V
FDS6676S
14.5A, 6mΩ
1 2 3
8 7 6 5
C2
22µF
16V
GND
V
CC
= 5V @ 30mA
QT
4
RLF
3.0,5%
CBST
1µF
DBST
MBR0530
1
VCC
GL
C1, C2
Ceramic
1210
X5R
U1
BST 10
GH 9
R5
Bead
8 7 6 5
R3
221k, 1%
UV
IN
R4
100k, 1%
C
VCC
10µF
6.3V
GND 3
2
3
4
SP6134
RZ3
4.64k, 1%
C3
47µF
6.3V
V
OUT
≤
VIN
0.8V - 3.3V
0 - 10 A
R1
68.1k, 1%
GND
VFB
COMP
SWN 8
SS 7
UVIN 6
QB
4
C4
47µF
6.3V
0.8V
5
SS
CSS
47nF
1 2 3
CZ3
220pF
C
VCC
Ceramic
8050
X5R
CF1
100pF
FDS6676S
14.5A, 6.0mΩ
CZ2
RZ2
GND2
C3, C4
Ceramic
1210
X5R
V
=(R1/R2 +1)V
OUT
FB
820pF 40.2k, 1%
CP1
56pF
fs=600Khz
R2
21.5k, 1%
Date: 2/16/06
SP6134 Dual Supply, Synchronous Buck Controller
© Copyright 2006 Sipex Corporation
1
ABSOLUTE MAXIMUM RATINGS
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.
V
CC
.................................................................................................. 7V
BST ............................................................................................... 22V
BST-SWN ......................................................................... -0.3V to 7V
SWN ................................................................................... -1V to 15V
GH ......................................................................... -0.3V to BST+0.3V
GH-SWN ......................................................................................... 7V
All other pins .......................................................... -0.3V to V
CC
+0.3V
Peak Output Current < 10us
GH,GL ............................................................................................. 2A
Storage Temperature .................................................. -65°C to 150°C
Power Dissipation .......................................................................... 1W
Lead Temperature (Soldering, 10 sec) ...................................... 300°C
ESD Rating .......................................................................... 2kV HBM
Thermal Resistance ............................................................. 41.9°C/W
ELECTRICAL SPECIFICATIONS
Unless otherwise specified: 0°C < T
AMB
< 70°C, 4.5V < V
CC
< 5.5V, BST=V
CC
,SWN = GND = 0V, UVIN = 3.0V, CV
CC
= 10µF,
C
COMP
= 0.1µF, CGH = CGL = 3.3nF, C
SS
= 50nF, Typical measured at V
CC
=5V. The
♦
denotes the specifications which
apply over the full operating temperature range, unless otherwise specified.
PARAMETER
QUIESCENT CURRENT
V
CC
Supply Current
BST Supply Current
PROTECTION: UVLO
V
CC
UVLO Start Threshold
V
CC
UVLO Stop Threshold
V
CC
UVLO Hysteresis
UVIN Start Threshold
UVIN Stop Threshold
UVIN Hysteresis
ERROR AMPLIFIER REFERENCE
Error Amplifier Reference
Error Amplifier Reference
Over Line and Temperature
Error Amplifier Transconductance
Error Amplifier Gain
COMP Sink Current
COMP Source Current
V
FB
Input Bias Current
Internal Pole
COMP Clamp
COMP Clamp Temp. Coefficient
Ramp Amplitude
RAMP Offset
RAMP Offset Temp. Coefficient
GH Minimum Pulse Width
Maximum Controllable Duty Ratio
Maximum Duty Ratio
Internal Oscillator Frequency
MIN
TYP
1.5
0.2
MAX
3
0.4
4.5
4.4
300
2.65
2.35
UNITS
mA
mA
V
V
mV
V
V
mV
♦
CONDITIONS
V
FB
=0.9V (No switching)
♦
V
FB
=0.9V (No switching)
4.00
3.80
100
2.3
2.0
4.25
4.05
200
2.5
2.2
300
♦
♦
♦
♦
0.792
0.788
0.800
0.800
6
60
150
150
50
4
2.5
-2
0.808
0.812
V
V
♦
2X Gain Config., Measure COMP/2
ms
dB
µA
µA
200
nA
MHz
V
mV/°C
1.28
V
V
mV/°C
180
ns
%
%
♦
♦
♦
♦
No Load
V
FB
= 0.9V, COMP = 0.9V
V
FB
= 0.7V, COMP = 2.2V
V
FB
= 0.8V
V
FB
=0.7V, T
A
= 25°C
CONTROL LOOP: PWM COMPARATOR, RAMP & LOOP DELAY PATH
0.92
1.1
1.1
-2
90
92
100
510
T
A
= 25°C, RAMP COMP
until GH starts switching
97
Maximum Duty Ratio Measured just
before pulse skipping begins
Valid for 20 Cycles
540
600
600
690
660
kHz
♦
Date: 2/16/06
SP6134 Dual Supply, Synchronous Buck Controller
© Copyright 2006 Sipex Corporation
2
ELECTRICAL SPECIFICATIONS: Continued
Unless otherwise specified: 0°C < T
AMB
< 70°C, 4.5V < V
CC
< 5.5V, BST=V
CC
,SWN = GND = 0V, UVIN = 3.0V, CV
CC
= 10µF,
C
COMP
= 0.1µF, CGH = CGL = 3.3nF, C
SS
= 50nF, Typical measured at V
CC
=5V. The
♦
denotes the specifications which
apply over the full operating temperature range, unless otherwise specified.
PARAMETER
TIMERS: SOFTSTART
SS Charge Current:
SS Discharge Current:
Short Circuit Threshold Voltage
Hiccup Timeout
Number of Allowable Clock Cycles
at 100% Duty Cycle
Minimum GL Pulse After 20 Cycles
Thermal Shutdown Temperature
Thermal Recovery Temperature
Thermal Hysteresis
OUTPUT: NFET GATE DRIVERS
GH & GL Rise Times
GH & GL Fall Times
GL to GH Non Overlap Time
SWN to GL Non Overlap Time
GH & GL Pull Down Resistance
Driver Pull Down Resistance
Driver Pull Up Resistance
MIN
TYP
10
MAX
UNITS
µA
mA
♦
CONDITIONS
1
0.2
0.25
100
20
0.5
145
135
10
35
30
45
20
50
1.5
2.5
1.9
3.0
50
40
70
30
0.3
♦
Fault Present, SS = 0.2V
Measured V
REF
(0.8V) - V
FB
V
FB
= 0V
V
FB
= 0.7V
V
FB
= 0.7V
PROTECTION: SHORT CIRCUIT & THERMAL
V
ms
Cycles
Cycles
°C
°C
°C
ns
ns
ns
ns
KΩ
Ω
Ω
♦
♦
♦
♦
♦
♦
♦
Measured 10% to 90%
Measured 90% to 10%
GH & GL Measured at 2.0V
Measured SWN = 100mV to GL = 2.0V
Resistor Pull-Down
Note 1
Note 1
Note 1: Gauranteed by design, not 100% tested.
Date: 2/16/06
SP6134 Dual Supply, Synchronous Buck Controller
© Copyright 2006 Sipex Corporation
3
PIN DESCRIPTION
PIN #
1
2
3
4
5
6
7
8
9
10
PIN NAME DESCRIPTION
V
CC
Bias Supply Input. Connect to external 5V supply. Used to power internal circuits and
low side gate driver.
GL
High current driver output for the low side NFET switch. It is always low if GH is high or
during a fault. Resistor pull down ensure low state at low voltage.
GND
Ground Pin. The control circuitry of the IC and lower power driver are referenced to this
pin. Return separately from other ground traces to the (-) terminal of C
OUT
.
V
FB
Feedback Voltage and Short Circuit Detection pin. It is the inverting input of the Error
Amplifier and serves as the output voltage feedback point for the Buck Converter. The
output voltage is sensed and can be adjusted through an external resistor divider.
Whenever V
FB
drops 0.25V below the positive reference, a short circuit fault is detected
and the IC enters hiccup mode.
COMP
Output of the Error Amplifier. It is internally connected to the non-inverting input of the
PWM comparator. An optimal filter combination is chosen and connected to this pin and
either ground or V
FB
to stabilize the voltage mode loop.
UVIN
UVLO input for V
IN
voltage. Connect a resistor divider between V
IN
and UVIN to set
minimum operating voltage.
SS
Soft Start. Connect an external capacitor between SS and GND to set the soft start rate
based on the 10µA source current. The SS pin is held low via a 1mA (min) current during
all fault conditions.
SWN
Lower supply rail for the GH high-side gate driver. Connect this pin to the switching node
at the junction between the two external power MOSFET transistors.
GH
High current driver output for the high side NFET switch. It is always low if GL is high or
during a fault. Resistor pull down ensure low state at low voltage.
BST
High side driver supply pin. Connect BST to the external boost diode and capacitor as
shown in the Typical Application Circuit on page 1. High side driver is connected between
BST pin and SWN pin.
Date: 2/16/06
SP6134 Dual Supply, Synchronous Buck Controller
© Copyright 2006 Sipex Corporation
4
