X RP 6 1 4 2
Synchronous Step-Down Controller with DDR
Memory Termination
March 2010
Rev. 1.0.0
GENERAL DESCRIPTION
The XRP6142 is a synchronous step down
switching controller for over 15 Amps point-of-
loads converters and optimized to generate
and support DDR I, II and III memory
voltages requirements.
Optimized to operate from standard 3.3V and
5V rails, the XRP6142 supports conversions
down to 0.5V from an input voltage as low as
1V and can reach efficiencies of up to 96%.
Based on a constant on-time control scheme
and operating at a constant switching
frequency over the whole input voltage range,
it provides excellent load transient response
while requiring no external compensation
components. Three selectable on-time options
allow for further switching frequency, solution
footprint and efficiency optimization.
Dedicated support for DDR I, II and II
memories is also provided. The XRP6142
easily generates V
DDQ
(V
DD
) or V
TT
voltages
while an on board buffer provides the buffered
V
TT
reference voltage.
Under-voltage Lock out, short-circuit and
over-current and over-temperature protection
insure safe operations under abnormal
operating conditions.
The XRP6142 is available in a compact RoHS
compliant “green”/halogen free 16-pin QFN
package.
APPLICATIONS
•
High-Power Point-of-Loads Converters
•
Audio-Video Equipments
•
FPGA and DSP Power Supplies
•
DDR Memory Based Embedded Systems
FEATURES
•
Over 15A Point-of-Load Capable
−
Down to 0.5V Output Voltage Conversion
−
Up to 96% Efficiency
•
Wide 1.0V-5.5V Input Voltage Range
Conversions
−
Single Input 3.3V and 5V rails Operations
•
Constant On-Time Operations
−
Constant Frequency Operations
−
No External Compensation
•
DDR I, II & III Termination Support
−
V
DDQ
/V
DD
or V
TT
Voltages Generation
−
Buffered V
TT
Ref. Voltage Generation
•
Soft-Start and Enable Functions
•
UVLO, Short Circuit and Over Current
Protection
•
RoHS Compliant “Green”/Halogen Free
3mm x 3mm 16-Pin QFN Package
TYPICAL APPLICATION DIAGRAM
Operation as DDR Supply
V
IN
C
IN
3V-5.5V
V
IN
V
CC
EN
GH
BST
SW
XRP6142
ILIM
GL
CS
GND
PGND
AGND
Thermal
Pad
FB
VDDQ/2
VDDQ
QT
L1
V
OUT
V
IN
C
OUT
R3
ACNTL
VOUT
VTT
V
REF
RLIM
QB
CFF
R1
R2
SP2996B
REF EN
REFIN
R4
GND
VREF
VTTREF
Figure. 1: XRP6142 as a Step-Down Converter or a DDR Supply
Exar Corporation
48720 Kato Road, Fremont CA 94538, USA
www.exar.com
Tel. +1 510 668-7000 – Fax. +1 510 668-7001
X RP 6 1 4 2
Synchronous Step-Down Controller with DDR
Memory Termination
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
...................................................................... 7.0V
V
IN
....................................................................... 7.0V
BST ....................................................................13.5V
SW ............................................................. -1V to 7.0V
BST-SW ...................................................... -0.3V to 6V
All other pins ..................................... -0.3V to V
CC
+0.3V
Storage Temperature .............................. -65°C to 150°C
Power Dissipation ................................ Internally Limited
Lead Temperature (Soldering, 10 sec) ................... 300°C
ESD Rating (HBM - Human Body Model) .................... 2kV
ESD Rating (MM - Machine Model) ...........................500V
OPERATING RATINGS
Input Voltage Range V
CC
.............................. 3.0V to 5.5V
Input Voltage Range V
IN
............................... 1.0V to 5.5V
Junction Temperature Range ....................-40°C to 125°C
Thermal Resistance
θ
JA
................................... 33.3°C/W
ELECTRICAL SPECIFICATIONS
Specifications are for an Operating Junction Temperature of T
J
= 25°C; limits applying over the full Operating Junction
Temperature range are denoted by a “•”. Minimum and Maximum limits are guaranteed through test, design, or statistical
correlation. Typical values represent the most likely parametric norm at T
J
= 25°C, and are provided for reference purposes
only. Unless otherwise indicated, V
CC
= V
IN
= 3.3V.
Parameter
V
REF
, Reference Voltage
V
FB
offset
V
REFIN
, Voltage Range
V
DDQ/2
, Input Impedance
V
TTREF
, Output Error
V
TTREF
Current Limit
I
Q
, Operating Quiescent Current
I
OFF
, Shutdown current
0.4
T
ON
, Switch On-Time
T
OFF_MIN
, Minimum Off-Time
T
D
, Gate Drive Dead-Time
V
IH_EN
, EN Pin Rising Threshold
V
EN_HYS
, EN Pin Hysteresis
I
FB
, Feedback Pin Bias Current
V
CCUVLO
, Under-Voltage Lockout
V
CCUVLO_HYS
, Under-Voltage Lock
out Hysteresis
V
SC_TH
, Feedback Pin Short
Circuit Latch Threshold
ILIM Pin Source Current
ILIM Current Temperature
Coefficient
V
ILIM
Current Limit Trip Level
Current Limit Blanking
-20
55
42.5
1.15
0.8
1.6
-1.25
±20
±40
400
0.1
0.5
1.0
2.0
300
50
1.2
50
50
2.8
500
65
50
0.3
0
130
+20
75
57.5
3.0
1.25
200
0.6
1.2
2.4
400
ns
ns
V
mV
nA
V
mV
%
µA
%/C
mV
ns
•
GL Rising > 1.0V
•
% of VREFIN
•
V
FB
=2.0V
V
CC
rising edge
•
µs
VREF
60
+1.25
±65
600
Min.
0.495
0.492
Typ.
0.5
0.5
7
1.3
Max.
0.505
0.508
Units
V
V
mV
V
MΩ
%
mA
µA
µA
•
•
•
•
•
•
V
DDQ/2
= 0.75V, I
VTTR
=0mA
Sourcing: V
TTREF
=0, V
DDQ/2
=V
REF
Sinking: V
TTREF
=2V
Not switching, V
FB
=V
REFIN
+0.1V
EN=0V
XR6142EL0-5-F
(T
ON
=500ns)
XR6142EL1-0-F (T
ON
=1000ns)
XR6142EL2-0-F (T
ON
=2000ns)
All T
ON
options
•
V
REFIN
= V
REF
Conditions
© 2010 Exar Corporation
Page 2 of 17
Rev. 1.0.0
X RP 6 1 4 2
Synchronous Step-Down Controller with DDR
Memory Termination
Parameter
Hiccup Timeout
Soft Start time
R
DS(ON)1
, GH FET driver pull-up
On resistance
R
DS(ON)2
, GH FET driver pull-down
On resistance
R
DS(ON)3
, GL FET driver pull-up On
resistance
R
DS(ON)4
, GL FET driver pull-down
On resistance
3
Min.
Typ.
110
5
2.5
2
2.5
2
10
Max.
Units
ms
ms
Ω
Ω
Ω
Ω
I
GH
=20 mA
I
GH
=20 mA
I
GL
=20 mA
I
GL
=20 mA
Conditions
0.5μs, 1μs and 2μs option, V
OUT
=1V
BLOCK DIAGRAM
Figure. 2: XRP6142 Block Diagram
© 2010 Exar Corporation
Page 3 of 17
Rev. 1.0.0
X RP 6 1 4 2
Synchronous Step-Down Controller with DDR
Memory Termination
PIN ASSIGNMENT
Figure. 3: XRP6142 Pin Assignment
PIN DESCRIPTION
Name
AGND
VTTREF
VDDQ/2
V
REF
REFIN
FB
CSGND
ILIM
PGND
GL
SW
GH
BST
V
IN
Vcc
EN
Thermal pad
Pin Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
-
Analog Ground
Buffered output of VDDQ/2
V
TT
reference voltage for DDR applications.
Buffer input voltage.
Voltage used for the input to the V
TTREF
buffer
Precision reference output
Reference input to the switching-regulator feedback comparator
Feedback input to feedback comparator
Current-sense ground
Connect a resistor between this pin and the low-side current-sense element in order to
set the current-limit-trip threshold. See applications section for instructions on how to
set this resistor
Gate driver GND.
Low-side N-channel MOSFET driver
Switch node for floating-high-side gate drive
High-side N-channel MOSFET driver
Bootstrap capacitor to drive the high-side gate driver, GH
Input voltage for the power train
Input voltage for the XRP6142 internal circuitry and gate drives. V
IN
and V
CC
can be tied
together when V
IN
≥
3.0V
Precision enable pin. Pulling this pin above 1.2V will turn the part on
Internally connected to AGND
Description
© 2010 Exar Corporation
Page 4 of 17
Rev. 1.0.0
X RP 6 1 4 2
Synchronous Step-Down Controller with DDR
Memory Termination
ORDERING INFORMATION
Part Number
XRP6142EL0-5-F
Temperature
Range
-40°C≤T
J
≤+125°C
-40°C≤T
J
≤+125°C
-40°C≤T
J
≤+125°C
-40°C≤T
J
≤+125°C
-40°C≤T
J
≤+125°C
-40°C≤T
J
≤+125°C
XRP6142 Evaluation
Marking
Package
Packing
Quantity
Note 1
RoHS Compliant
Halogen Free
RoHS Compliant
Halogen Free
RoHS Compliant
Halogen Free
RoHS Compliant
Halogen Free
RoHS Compliant
Halogen Free
RoHS Compliant
Halogen Free
Note 2
0.5µs on time
XRP6142ELTR0-5-F
XRP6142EL1-0-F
XRP6142ELTR1-0-F
XRP6142EL2-0-F
XRP6142ELTR2-0-F
XRP6142EVB
6142E
Bulk
YYWW05
16-pin QFN
X
6142E
3K/Tape & Reel
YYWW05
16-pin QFN
X
6142E
Bulk
YYWW10
16-pin QFN
X
6142E
3K/Tape & Reel
YYWW10
16-pin QFN
X
6142E
Bulk
YYWW20
16-pin QFN
X
6142E
3K/Tape & Reel
YYWW20
16-pin QFN
X
Board – XRP6142EL2-0-F based
0.5µs on time
1.0µs on time
1.0µs on time
2.0µs on time
2.0µs on time
“YY” = Year – “WW” = Work Week – “X” = Lot Number
© 2010 Exar Corporation
Page 5 of 17
Rev. 1.0.0
