Exar XRP6141 User manual

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November 2013
Rev. 1.0.0
Exar Corporation www.exar.com
48720 Kato Road, Fremont CA 94538, USA Tel. [phone] – Fax. [phone]
GENERAL DESCRIPTION
The XRP6141 is a synchronous step-down
controller for point-of load supplies up to 35A.
A wide 4.5V to 22V input voltage range allows
for single supply operation from industry
standard 5V, 12V and 19.6V rails.
With a proprietary emulated current mode
Constant On-Time (COT) control scheme, the
XRP6141 provides extremely fast line and load
transient response using ceramic output
capacitors. It requires no loop compensation
hence simplifying circuit implementation and
reducing overall component count. The
control loop also provides exceptional line
regulation and maintains constant operating
frequency. A selectable power saving mode,
allows the user to operate in discontinuous
mode (DCM) at light current loads thereby
significantly increasing the converter
efficiency.
A host of protection features, including over-
current, over-temperature, short-circuit and
UVLO, help achieve safe operation under
abnormal operating conditions.
E
EV VA AL LU UA AT TI IO ON N B BO OA AR RD D M MA AN NU UA AL L
FEATURES
•35A Capable Step Down Controller
−Wide Input Voltage Range
o5V to 22V Single Supply
o4.5V to 5.5V Low Vin
−Integrated high Current 2A/3A Drivers
−0.6V to 18V Adjustable Output Voltage
•Proprietary Constant On-Time Control
−No Loop Compensation Required
−Ceramic Output Cap. Stable operation
−Programmable 200ns-2µs
−Quasi Constant 200kHz-800kHz Freq.
−Selectable CCM or CCM/DCM Operation
Fig. 1: XRP6141 Evaluation Board Schematics
For ced CC M DCM/CCM
J1
1
1
2
2
3
3
R3
0 Ohm
R8 1k,
R9 2.5k,
U1
XRP6141
GL 1
SW 3
NC 2
GH 4
SS
9
PGOOD
10
FB
11
AGND
12
BST 5
ILIM 6
EN 7
TON 8
AGND
13
VIN
14
VCC
15
PGND
16
EXPAD
17
VCC
1.2V @ 0-25A
12V
Csnub
6.8nF
C1
22uF
CVCC 4.7uF
VOUT+
T1
PWRGD
C1,C2,C3,C4
CERAM IC 1210 X7R
C2
22uF
VOUT-
L1 IHLP-5050FD -01
0.47uH @ 41A, 1mOhm
C3
22uF
C4
22uF
R1
10k,1%
VIN
CBST 1uF
R2
10k,1%
CSS
47nF
EN/MODE
CIN 0.1uF
R6 2k
T2
R7 6k,
T9
T10
T5
T7
T6
R4 10k
R5
OPEN
AGND
CFF
0.56nF
MT
FDMS7578
C6
330uF
C7
330uF
C8
330uF
D1 MMSZ 4699T1G
C10
OPEN
VIN
T8
T3
T4
RON 11.8k
VIN+
MB
FDMS7650DC
C5
22uF
C11
OPEN
C12
OPEN
RBST
0 Ohm
RLIM 1.8k,1%
C9
330uF
Rsnub
1 Ohm
VIN-
C5,C6,C7,C8 POSCAP
2R5TPE330M 7
C13
OPEN

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© 2013 Exar Corporation 2/7 Rev. 1.0.0
PIN ASSIGNMENT
Fig. 2: XRP6141 Pin Assignment
PIN DESCRIPTION
Name Pin Number Description
GL
1 Driver output for Low-side N-channel synchronous MOSFET.
NC 2 Internally not connected. Leave this pin floating.
SW 3 Lower supply rail for high-side gate driver GH. Connect this pin to the junction between
the two external N-channel MOSFETs.
GH 4 Driver output for high-side N-channel switching MOSFET.
BST 5 High-side driver supply pin. Connect a 0.1uF bootstrap capacitor between BST and SW.
ILIM 6 Over-current protection programming. Connect with a resistor to the Drain of the low-
side MOSFET.
EN/MODE 7
Precision enable pin. Pulling this pin above 1.9V will turn the IC on and it will operate in
Forced CCM. If the voltage is raised above 3.0V then the IC will operate in DCM or CCM
depending on load.
TON 8 Constant on-time programming pin. Connect with a resistor to AGND.
SS 9 Soft-Start pin. Connect an external capacitor between SS and AGND to program the
soft-start rate based on the 10uA internal source current.
PGOOD 10 Power-good output. This open-drain output is pulled low when VOUT is outside the
regulation.
FB 11 Feedback input to feedback comparator. Connect with a set of resistors to VOUT and
GND in order to program VOUT.
AGND 12, 13 Analog ground. Control circuitry of the IC is referenced to this pin.
VIN 14 IC supply input. Provides power to internal LDO.
VCC
15 The output of LDO. For operation using a 5V rail, VCC should be shorted to VIN.
PGND
16 Ground for low side driver
Exposed Pad Thermal pad for heat dissipation. Connect to AGND with a short trace.
ORDERING INFORMATION
Refer to XRP6141’s datasheet and/or www.exar.com for exact and up to date ordering information.
1
2
3
4
5678
9
131415
10
12
16
11
GL
NC
SW
GH
BST ILIM EN TON
SS
PGOOD
FB
AGND
AGNDVINPGND VCC
EXPOSED PAD

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© 2013 Exar Corporation 3/7 Rev. 1.0.0
USING THE EVALUATION BOARD
POWERING UP
Connect the VIN+/VIN- with short/thick leads
to power supply. Connect VOUT+/VOUT- with
short/thick leads to electronic load. Apply 12V
using the power supply. The XRP6141EVB
should power up and regulate the output at
1.2V. Rated output current is 25A. Overcurrent
protection should trigger at about 34A.
JUMPER J1
With the jumper set at CCM position the
converter will operate in ‘Forced CCM’ at
VIN=12V(+/-10%). In order to operate in
Forced CCM over a wider VIN range, remove
Jumper and apply an auxilary voltage in the
range of 1.9V-3V to the EN test point.
With the jumper set at DCM/CCM position the
converter will operate at DCM/CCM, depending
on load, at VIN=12V(+/-10%). In order to
operate in DCM/CCM over a wider VIN range,
remove Jumper and apply an auxilary voltage
in the range of 3.1V-5V to the EN test point.

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© 2013 Exar Corporation 4/7 Rev. 1.0.0
EVALUATION BOARD SCHEMATICS
Forced C CM DCM/CCM
J1
1
1
2
2
3
3
R3
0 Ohm
R8 1k,R9 2.5k,
U1
XRP6141
GL 1
SW 3
NC 2
GH 4 SS
9
PGOOD
10
FB
11
AGND
12
BST 5
ILIM 6
EN 7
TON 8
AGND
13
VIN
14
VCC
15
PGND
16
EXPAD
17
VCC
1.2V @ 0-25A
12V
Csnub
6.8nF
C1
22uF
CVCC 4.7uF
VOUT+
T1
PWRGD
C1,C2,C3,C4
CERAMIC 1210 X7R
C2
22uF
VOUT-
L1 IHLP- 5050FD-01
0.47uH @ 41A, 1mOhm
C3
22uF
C4
22uF
R1
10k,1%
VIN
CBST 1uF
R2
10k,1%
CSS
47nF
EN/MODE
CIN 0.1uF
R6 2k
T2
R7 6k,
T9
T10
T5
T7
T6
R4 10k
R5
OPEN
AGND
CFF
0.56nF
MT
FDMS7578
C6
330uF
C7
330uF
C8
330uF
D1 MMSZ4699T1G
C10
OPEN
VIN
T8
T3
T4
RON 11.8k
VIN+
MB
FDMS7650DC
C5
22uF
C11
OPEN
C12
OPEN
RBST
0 Ohm
RLIM 1.8k,1%
C9
330uF
Rsnub
1 Ohm
VIN-
C5,C6,C7,C8 POSCAP
2R5TPE330M7
C13
OPEN

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© 2013 Exar Corporation 5/7 Rev. 1.0.0
BILL OF MATERIAL
Reference Qty. Manufacturer Manufacturer Size Component
Designator Part Number
PCB 1Exar XRP6141EVB XRP6141 Evaluation kit
U1 1Exar XRP6141 QFN-16 Constant On-Time Buck co ntroller
MT 1F AIRC HILD FDMS7578 Power SO-8 N-Ch. 25V, 5.8mOhm MOSFET
MB 1F AIRC HILD FDMS7650DC Power SO-8 N-Ch. 30V, 100A, 0.99mOhm, MOSFET
D1 1ON SEMI MMSZ4699T1G SOD-123 Diode Zener 12V, 500MW,
L1 1VISHAY-DALE IHLP5050FDERR47M01 13.2x12.9mm
Shielded inductor, 0.47uH, 1mΩ, 41A
C1-C4 4MURATA GRM32ER71E226KE15L
1210 CERAMIC CAP., 22uF, 25V, X7R, 10%
C5 0DONT POPULATE ---
--- ---
C6-C9 4PANASONIC 2R5TPE330M7 7.3X4.3X1.8mm TANTALUM CAP., 330uF, 2.5V, 2917
C10-C13 0DONT POPULATE --- --- ---
CBST 1MURATA GRM188R71C105KA12D 0603 CERAMIC CAP. , 1uF, 16V, X7R, 10%
CFF 1MURATA GRM188R71H561KA01D 0603 CERAMIC CAP , 0.56nF, 50V, X7R, 10%
C IN 1MURATA GRM188R71H104KA93D 0603 CERAMIC CAP., 0.1uF, 50V, X7R, 10%
CVCC 1MURATA GRM21BR71C475KA73L 0805 CERAMIC AP. , 4.7uF, 16V, X7R, 10%
CSS 1MURATA GRM188R71H473KA61D 0603 CERAMIC CER, 47nF, 50V, X7R, 10%
Csnub 1MURATA GRM188R71H682KA01D 0603 CERAMIC CER, 6.8nF, 50V, X7R, 10%
R1, R2, R4 3PANASONIC ERJ-3EKF1002V 0603
Resistor 10k
, 1/10W, 1%, SMD
R3, RBST 2PANASONIC ERJ-3GEY0R00V 0603
Resistor 0Ω, Jumper SMD
R5 0DONT POPULATE --- --- ---
R9 1PANASONIC ERJ-3EKF2491V 0603 Resistor 2.49K Ohm, 1/10w, 1%, SMD
R6 1PANASONIC ERJ-3EKF2001V 0603 Resistor 2K Ohm, 1/10W, 1%, SMD
R7 1PANASONIC ERJ-3EKF6041V 0603 Resistor 6.04K Ohm, 1/10W, 1%, SMD
R8 1PANASONIC ERJ-3EKF1001V 0603 Resistor 1K Ohm, 1/10W, 1%, SMD
RLIM 1PANASONIC ERJ-3EKF1821V 0603 Resistor 1.82k, 1/10W, 1%, SMD
RON 1PANASONIC ERJ-3EKF1182V 0603
Resisrtor 11.8K Ohm ohm, 1/10W,1%, SMD
Rsnub 1PANASONIC ERJ-6RQF1R0V 0805 Resisrtor 1.0 Ohm, 1/8W,1%, SMD
J1 1Wurth Elektronik 61300311121 3-PIN CONNECTOR
VIN+, VIN-, VOUT+, VOUT- 4POMONA 3267 1/4-32 Banana Jack
T3/T4, T5/T6, T7/T8,
AGND/VCC
8Wurth Elektronik 61300211121 DUAL TEST POINT
T1, T2, T9, T10, PWERGD,
EN/MODE
6Wurth Elektronik 61300111121 SINGLE Test Point Post
STAND1, STAND 2 2Keystone 4-40 X 1/2 STANDOFF

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© 2013 Exar Corporation 6/7 Rev. 1.0.0
EVALUATION BOARD LAYOUT
Fig. 3: Component Placement – Top Side
Fig. 4: Bottom Side
Fig. 5: Layer 2
Fig. 6: Layer 3

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35 5A A S Sy yn nc ch hr ro on no ou us s S St te ep p D Do ow wn n C CO OT T C Co on nt tr ro ol ll le e
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© 2013 Exar Corporation 7/7 Rev. 1.0.0
DOCUMENT REVISION HISTORY
Revision Date Description
1.0.0 11/22/13 Initial release of document
BOARD REVISION HISTORY
Board Revision Date Description
146-6702-03 11/22/13 Initial release of evaluation board
FOR FURTHER ASSISTANCE
Email: [e-mail]
[e-mail]
Exar Technical Documentation: http://www.exar.com/TechDoc/default.aspx?
EXAR CORPORATION
HEADQUARTERS AND SALES OFFICES
48720 Kato Road
Fremont, CA 94538 – USA
Tel.: [phone]
Fax: [phone]
www.exar.com
NOTICE
EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve
design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any circuits described herein,
conveys no license under any patent or other right, and makes no representation that the circuits are free of patent
infringement. Charts and schedules contained here in are only for illustration purposes and may vary depending upon a
user’s specific application. While the information in this publication has been carefully checked; no responsibility, however,
is assumed for inaccuracies.
EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or
malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its
safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, in
writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes all
such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances.
Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited.