X
X
R
R
P
P
6
6
1
1
4
4
1
1
3
3
5
5
A
A
S
S
y
y
n
n
c
c
h
h
r
r
o
o
n
n
o
o
u
u
s
s
S
S
t
t
e
e
p
p
D
D
o
o
w
w
n
n
C
C
O
O
T
T
C
C
o
o
n
n
t
t
r
r
o
o
l
l
l
l
e
e
r
r
November 2013
Rev. 1.0.0
Exar Corporation
48720 Kato Road, Fremont CA 94538, USA
Tel. +1 510 668-7000 – Fax. +1 510 668-7001
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
E
V
V
A
A
L
L
U
U
A
A
T
T
I
I
O
O
N
N
B
B
O
O
A
A
R
R
D
D
M
M
A
A
N
N
U
U
A
A
L
L
FEATURES
•
35A Capable Step Down Controller
−
Wide Input Voltage Range
o
5V to 22V Single Supply
o
4.5V 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
Forced CCM
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
IL
IM
6
EN
7
T
ON
8
AGN
D
13
VI
N
14
VC
C
15
PGN
D
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
