FEATURES
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LTC7130
20V 20A Monolithic Buck
Converter with Ultralow
DCR Sensing
DESCRIPTION
The
LTC
®
7130
is a current mode synchronous step-down
monolithic converter that can deliver up to 20A continuous
load current. It employs a unique architecture which enhances
the signal-to-noise ratio of the current sense signal, allow-
ing the use of a very low DC resistance power inductor to
maximize efficiency in high current applications. This feature
also reduces the switching jitter commonly found in low
DCR applications. The LTC7130 also includes a high speed
differential remote sense amplifier and a programmable cur-
rent sense limit that can be selected from 10mV to 30mV to
set the output current limit up to 20A. In addition, the DCR
temperature compensation feature limits the maximum
output current precisely over temperature.
The LTC7130 also features a precise 0.6V reference with a
guaranteed limit of ±0.5% that provides an accurate output
voltage. A 5V to 20V input voltage range supports a wide
variety of bus voltages and various types of batteries.
The LTC7130 is offered in a compact and low profile BGA pack-
age available with SnPb/RoHS compliant terminal finishes.
L,
LT, LTC, LTM, Burst Mode, OPTI-LOOP, μModule, Linear Technology and the Linear logo are
registered trademarks and No R
SENSE
is a trademark of Analog Devices, Inc. All other trademarks
are the property of their respective owners. Protected by U.S. Patents, including 5481178,
5705919, 5929620, 6177787, 6580258, 6498466, 6611131, patent pending.
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Wide V
IN
Range: 4.5V to 20V
Optimized for Low Duty Cycle Applications
High Efficiency: Up to 95%
LTC Proprietary Current Mode Architecture
High Current Parallel Operation
Ultralow DCR Current Sensing with
Temperature Compensation
Programmable Output Current Limit
High Speed Differential Remote Sense Amplifier
±0.5% Output Voltage Regulation Accuracy
Output Short-Circuit Protection with Soft Recovery
Programmable Soft-Start, Tracking
Programmable Fixed Frequency: 250kHz to 770kHz
EXTV
CC
for Reduced Power Dissipation
Fault Indicator for Output UV/OV Conditions
6.25mm
×
7.5mm
×
2.22mm BGA Package
APPLICATIONS
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DSP FPGA, ASIC Reference Designs
,
Telecom/Datacom Systems
Distributed High Power Density Systems
TYPICAL APPLICATION
High Efficiency, 1.5V/20A Step-Down Converter with Very Low DCR Sensing
V
IN
= 5V
TO 20V
2.2Ω
Efficiency vs Load Current
100
14
EFFICIENCY
12
10
8
V
IN
= 12V
V
OUT
= 1.5V
L = 0.25 H (DCR = 0.37mΩ)
EXTV
CC
= 5V
CCM
POWER LOSS
0
2
4
6 8 10 12 14 16 18 20
LOAD CURRENT (A)
7130 TA01b
+
470µF
INTV
CC
SVIN
V
IN
ILIM
1k
RUN
MODE/PLLIN
220pF
ITH
TK/SS
0.1µF
EXTV
CC
V
FB
20k
30.1k
DIFFOUT
1µF
4.7µF
INTV
CC
ITEMP
BOOST
SW
SNSD
+
LTC7130
SNS
–
SNSA
+
DIFFP
DIFFN
2.2Ω
0.1µF
3.09k
CMDSH2-3
0.25µH
(0.37m
DCR)
90
80
V
OUT
1.5V
20A
470µF
×2
EFFICIENCY (%)
70
60
50
40
30
20
10
0
PINS NOT USED
IN THIS CIRCUIT:
PGOOD
CLKOUT
3.01k
POWER LOSS (W)
+
6
4
2
0
220nF
220nF
619Ω
121k
1nF
20k
SGND
GND
FREQ
7130 TA01a
7130fb
For more information
www.linear.com/LTC7130
1
LTC7130
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
1
A
B
C
D
E
F
G
SW
H
J
BGA PACKAGE
63-PIN (6.25mm
×
7.5mm
×
2.22mm)
GND
BOOST
V
IN
NC1
2
DIFFN
3
TOP VIEW
4
5
6
V
FB
RUN
7
NC2
FREQ
DIFFP DIFFOUT ITH
TK/SS
Input Supply Voltage .................................. –0.3V to 20V
EXTV
CC
, RUN, PGOOD ................................. –0.3V to 6V
SNSD
+
, SNSA
+
, SNS
–
Voltages ............. –0.3V to INTV
CC
MODE/PLLIN, ILIM, TK/SS, FREQ......... –0.3V to INTV
CC
DIFFP, DIFFN ......................................... –0.3V to INTV
CC
ITEMP, ITH, V
FB
Voltages ...................... –0.3V to INTV
CC
Operating Junction Temperature Range
(Note 2).................................................. –40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
Peak Solder Reflow Body Temperature ................. 260°C
SNSD
+
SNS
–
SNSA
+
INTV
CC
GND
ILIM CLKOUT SGND
MODE/
PLLIN PGOOD
SV
IN
ITEMP EXTV
CC
T
JMAX
= 125°C,
θ
JA
= 21°C/W,
θ
JC
= 10°C/W
θ
JA
DERIVED FROM LTC7130 DEMO BOARD, Weight = 0.24g
ORDER INFORMATION
PART NUMBER
LTC7130EY#PBF
LTC7130IY#PBF
PAD OR BALL FINISH
SAC305 (RoHS)
SAC305 (RoHS)
(http://www.linear.com/product/LTC7130#orderinfo)
PART MARKING*
DEVICE
LTC7130
LTC7130
FINISH CODE
e1
e1
PACKAGE
TYPE
BGA
BGA
MSL
RATING
3
3
TEMPERATURE RANGE
(SEE NOTE 2)
–40°C to 125°C
–40°C to 125°C
• Device temperature grade is indicated by a label on the shipping container.
• Pad or ball finish code is per IPC/JEDEC J-STD-609.
• Terminal Finish Part Marking:
www.linear.com/leadfree
• This product is not recommended for second side reflow. For more
information, go to
www.linear.com/BGA-assy
• Recommended BGA PCB Assembly and Manufacturing Procedures:
www.linear.com/BGA-assy
• BGA Package and Tray Drawings:
www.linear.com/packaging
• This product is moisture sensitive. For more information, go to:
www.linear.com/BGA-assy
ELECTRICAL CHARACTERISTICS
SYMBOL
V
IN
V
OUT
V
FB
PARAMETER
Input Voltage Range
Output Voltage Range
Regulated Feedback Voltage
CONDITIONS
(Note 3)
Main Control Loops
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 12V, V
RUN
= 5V unless otherwise specified.
MIN
4.5
0.6
0.6
l
l
TYP
MAX
20
3.5
5.5
UNITS
V
V
V
V
V
7130fb
with Diffamp Low DCR Sensing
without Diffamp and No Low DCR Sensing
Current ITH Voltage = 1.2V (Note 4)
–40°C to 85°C
–40°C to 125°C
0.597
0.5955
0.6
0.6
0.603
0.6045
2
For more information
www.linear.com/LTC7130
LTC7130
ELECTRICAL CHARACTERISTICS
SYMBOL
I
FB
V
REFLNREG
V
LOADREG
g
m
I
Q
UVLO
UVLO
HYS
V
FBOVL
I
SNSD
+
I
SNSA
+
A
VT_SNS
PARAMETER
Feedback Current
Reference Voltage Line
Regulation
Output Voltage Load
Regulation
Error Amplifier (EA)
Transconductance
Input DC Supply Current
Normal Mode
Shutdown
Undervoltage Lockout
UVLO Hysteresis Voltage
Feedback Overvoltage Lockout Measured at V
FB
SNSD
+
Pin Bias Current
SNSA
+
Pin Bias Current
Total Sense Signal Gain to
Current Comparator
–40°C to 125°C
V
SNS
– = 1.8V, I
LIM
= 0V
I
LIM
= 1/4V
INTVCC
I
LIM
= 1/2V
INTVCC
or Float
I
LIM
= 3/4V
INTVCC
I
LIM
= V
INTVCC
l
l
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 12V, V
RUN
= 5V unless otherwise specified.
CONDITIONS
(Note 4)
V
IN
= 4.5V to 20V (Note 4)
(Note 4)
Measured in Servo Loop;
∆ITH
Voltage = 1.2V to 0.7V
Measured in Servo Loop;
∆ITH
Voltage = 1.2V to 1.6V
ITH =1.2V, Sink/Source 5µA (Note 4)
(Note 5)
V
RUN
= 0V
V
INTVCC
Ramping Down
3.4
0.64
MIN
TYP
–15
0.002
MAX
–50
0.02
UNITS
nA
%
l
l
0.01
0.01
2
0.1
0.1
%
%
mmho
3.8
30
3.75
0.5
0.66
30
1
5
50
4.1
0.68
100
2
mA
µA
V
V
V
nA
µA
V/V
V
SNSD
+ = 3.3V
V
SNSA
+ = 3.3V
V
SENSE(MAX)
Maximum Current Sense
Threshold
8.8
14
19
23.5
28.3
9
1.0
1.1
10
15
20
25
30
10
1.25
1.22
80
11.2
16
21
26.5
31.7
11
1.5
1.35
mV
mV
mV
mV
mV
µA
µA
V
mV
ns
I
TEMP
I
TK/SS
V
RUN
V
RUN(HYS)
t
ON(MIN)
V
INTVCC
V
EXTVCC
DCR Temperature
Compensation Current
Soft-Start Charge Current
RUN Pin on Hysteresis
Voltage
Minimum On-Time
Internal V
CC
Voltage
Load Regulation
External V
CC
Switchover
Voltage
EXTV
CC
Voltage Drop
EXTV
CC
Hysteresis
V
ITEMP
= 0.3V
V
TK/SS
= 0V
RUN Pin on Threshold Voltage V
RUN
Rising
(Note 6)
6V < V
IN
< 20V
I
INTVCC
= 0mA to 20mA
EXTV
CC
Ramping Positive
I
EXTVCC
= 20mA, V
EXTVCC
= 5.5V
4.5
5.25
90
5.5
0.5
4.7
40
250
100
5.75
2
INTV
CC
Linear Regulator
V
%
V
mV
mV
550
275
850
11
kHz
kHz
kHz
kΩ
µA
Oscillator and Phase-Locked Loop
f
NOM
f
LOW
f
HIGH
I
FREQ
Nominal Frequency
Lowest Frequency
Highest Frequency
Frequency Setting Current
V
FREQ
= 1.2V
V
FREQ
= 0.4V
V
FREQ
> 2.4V
450
225
700
9
500
250
770
250
10
R
MODE/PLLIN
MODE/PLLIN Input Resistance
7130fb
For more information
www.linear.com/LTC7130
3
LTC7130
ELECTRICAL CHARACTERISTICS
SYMBOL
CLKOUT
CLKOUT
HI
CLKOUT
LO
V
PGDLO
I
PGD
V
PGD
PARAMETER
Phase Relative to the
Oscillator Clock
Clock Output High Voltage
Clock Output Low Voltage
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip
I
PGOOD
= 2mA
V
PGOOD
= 5.5V
V
FB
with Respect to Set Output Voltage
V
FB
Going Negative
V
FB
Going Positive
–40°C to 125°C
Measured at DIFFP Input
V
DIFFP
= 1.5V, V
DIFFOUT
= 100µA
5V < V
IN
< 20V (Note 7)
1.5
V
INTVCC
= 5.5V, I
DIFFOUT
= 300µA
(Note 7)
(Note 7)
90
2
l
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 12V, V
RUN
= 5V unless otherwise specified.
CONDITIONS
MIN
TYP
180
V
INTVCC
= 5.5V
4.5
5.5
0
0.1
0.2
0.3
2
–10
10
0.997
1
80
2
1.003
MAX
UNITS
Deg
V
V
V
µA
%
%
V/V
kΩ
mV
dB
mA
V
MHz
V/µs
mΩ
mΩ
PGOOD Output
Differential Amplifier
A
V
R
IN
V
OS
PSRR
I
OUT
V
OUT
GBW
SR
R
DS(ON)
R
TOP
R
BOTTOM
Top Power NMOS On-
Resistance
Bottom Power NMOS On-
Resistance
7.3
2.1
Gain
Input Resistance
Input Offset Voltage
Power Supply Rejection Ratio
Maximum Sourcing Output
Current
Maximum Output Voltage
Gain-Bandwidth Product
Slew Rate
V
INTVCC
– 1.4 V
INTVCC
– 1.1
3
2
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
The LTC7130 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC7130E is guaranteed to meet performance specifications
from 0°C to 85°C operating junction temperature. Specifications over
the –40°C to 125°C operating junction temperature range are assured by
design, characterization and correlation with statistical process controls.
The LTC7130I is guaranteed to meet performance specifications over the
full –40°C to 125°C operating junction temperature range. The maximum
ambient temperature consistent with these specifications is determined
by specific operating conditions in conjunction with board layout, the
package thermal impedance and other environmental factors. The thermal
derating curves are based on the LTC7130 demo board.
Note 3:
When 4.5V ≤ V
IN
≤ 5.5V, INTV
CC
must be tied to V
IN
. Guaranteed
by design.
Note 4:
The LTC7130 is tested in a feedback loop that servos V
ITH
to a
specified voltage and measures the resultant V
FB
.
Note 5:
Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
Note 6:
The minimum on-time condition corresponds to the on inductor
peak-to-peak ripple current ≥40% of I
MAX
(see Minimum On-Time
Considerations in the Applications Information section).
Note 7:
Guaranteed by design.
4
7130fb
For more information
www.linear.com/LTC7130
LTC7130
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs Load Current
and Mode
100
90
80
EFFICIENCY (%)
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0.1
V
OUT
= 1.5V
L = 0.25 H (DCR = 0.37mΩ)
FRONT PAGE CIRCUIT
CCM
Burst Mode OPERATION
PULSE–SKIPPING MODE
1
10
LOAD CURRENT (A)
100
3681 G01
T
A
= 25°C, unless otherwise noted.
Efficiency vs Load Current
and Mode
Efficiency vs Load Current
and Mode
V
IN
= 5V
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0.1
V
OUT
= 1.5V
L = 0.25 H (DCR = 0.37mΩ)
FRONT PAGE CIRCUIT
CCM
Burst Mode OPERATION
PULSE–SKIPPING MODE
1
10
LOAD CURRENT (A)
100
3681 G02
f
SW
= 500kHz
f
SW
= 500kHz
V
IN
= 12V
100
90
80
70
60
50
40
30
20
10
f
SW
= 400kHz
V
IN
= 12V
EXTV
CC
= 5V
V
OUT
= 1V
L = 0.25 H (DCR = 0.37mΩ)
FRONT PAGE CIRCUIT
CCM
Burst Mode OPERATION
PULSE–SKIPPING MODE
1
10
LOAD CURRENT (A)
100
3681 G03
0
0.1
Efficiency and Power Loss
vs Load Current
vs Load Current
V
IN
= 20V
EFFICIENCY
10
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0
3
POWER LOSS
6
9
11
14
LOAD CURRENT (A)
17
20
7130 G04
Load Step
(Burst Mode
®
Operation)
(Burst Mode Operation)
15
V
OUT
AC–COUPLED
100mV/DIV
POWER LOSS (W)
V
OUT
AC–COUPLED
100mV/DIV
Load Step
(Continuous Conduction Mode)
V
OUT
= 1.5V
5
I
LOAD
5A/DIV
1A to 15A
V
IN
= 12V
V
OUT
= 1.5V
FRONT PAGE CIRCUIT
20µs/DIV
7130 G05
I
LOAD
5A/DIV
1A to 15A
V
IN
= 12V
V
OUT
= 1.5V
FRONT PAGE CIRCUIT
20µs/DIV
7130 G06
0
Load Step
(Pulse-Skipping Mode)
V
OUT
AC–COUPLED
100mV/DIV
CONTINUOUS
CONDUCTION
MODE 10A/DIV
Burst Mode
OPERATION
10A/DIV
I
LOAD
5A/DIV
1A TO 15A
20µs/DIV
7130 G07
Inductor Current at Light Load
Prebiased Output at 1V
V
OUT
500mV/DIV
TRACK/SS 500mV/DIV
V
FB
500mV/DIV
PULSE–SKIP
MODE
10A/DIV
V
IN
= 12V
V
OUT
= 1.5V
FRONT PAGE CIRCUIT
V
IN
= 12V
V
OUT
= 1.5V
LOAD
= 300mA
10µs/DIV
7130 G08
V
IN
= 12V
V
OUT
= 1.5V
20ms/DIV
7130 G09
7130fb
For more information
www.linear.com/LTC7130
5
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