LTM8027EV#PBF [Linear]
LTM8027 - 60V, 4A DC/DC µModule (Power Module) Regulator; Package: LGA; Pins: 113; Temperature Range: -40°C to 85°C;
| 型号： | LTM8027EV#PBF |
| 厂家： | 
Linear |
| 描述： | LTM8027 - 60V, 4A DC/DC µModule (Power Module) Regulator; Package: LGA; Pins: 113; Temperature Range: -40°C to 85°C 开关 |
| 文件： | 总22页 (文件大小：608K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTM8027
60V, 4A DC/DC
µModule Regulator
FEATURES
DESCRIPTION
The LTM®8027 is a complete 4A, DC/DC step-down power
supply. Included in the package are the switching control-
ler,powerswitches,inductorandallsupportcomponents.
Operatingoveraninput voltage rangeof4.5V to 60V (7.5V
minimum voltage to start), the LTM8027 supports output
voltages up to 24V, and a switching frequency range of
100kHz to 500kHz, each set by a single resistor. Only
the bulk input and output filter capacitors are needed to
finish the design.
n
Complete Switch Mode Power Supply
n
Wide Input Voltage Range: 4.5V to 60V
(7.5V Minimum Voltage to Start)
Wide Output Voltage Range: 2.5V to 24V
n
(See Table 2)
4A Output Current
Programmable Soft-Start
9µA Shutdown Supply Current
n
n
n
n
Selectable Switching Frequency Current Mode
Control
Up to 95% Efficiency
The low profile package (4.32mm) enables utilization of
unused space on the bottom of PC boards for high den-
sity point of load regulation. A built-in soft-start timer is
adjustable with a small capacitor.
n
n
SnPb (BGA) or RoHS Compliant (LGA and BGA)
Finish
n
Surface Mount LGA (15mm × 15mm × 4.32mm)
The LTM8027 is packaged in a compact (15mm × 15mm
×4.32mm)over-moldedlandgridarray(LGA)and(15mm
× 15mm × 4.92mm) BGA package suitable for automated
assembly by standard surface mount equipment. The
LTM8027 is available with SnPb (BGA) or RoHS compli-
ant terminal finish.
and (15mm × 15mm × 4.92mm) BGA Packages
APPLICATIONS
n
12V and 42V Automotive and Heavy Equipment
n
48V Telecom Power Supplies
L, LT, LTC, LTM, Linear Technology, the Linear logo and µModule are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
n
Avionics and Industrial Control Systems
Distributed Power Converters
n
TYPICAL APPLICATION
48W, 16VIN to 60VIN DC/DC µModule® Regulator
Efficiency vs Load
V
100
OUT
V
24V
IN
IN
12V
V
V
OUT
IN
16V TO 60V
90
80
70
60
50
40
30
20
10
0
4.7µF
×2
4A
1M
LTM8027
RUN
SS
BIAS1
BIAS2
AUX
22µF
×4
SYNC
RT
ADJ
GND
48.7k
56.2k
3845 TA01a
0
1
2
3
4
LOAD (A)
8027 TA01b
8027fd
1
For more information www.linear.com/LTM8027
LTM8027
ABSOLUTE MAXIMUM RATINGS
(Note 1)
V Voltage................................................................65V
Current Out of AUX ............................................. 200mA
Internal Operating Temperature (Note 3)
E-, I-Grade ......................................... –40°C to 125°C
MP-Grade .......................................... –55°C to 125°C
Peak Solder Reflow Body Temperature ................. 245°C
Storage Temperature Range .................. –55°C to 125°C
IN
BIAS1........................................................................15V
BIAS2........................................................................24V
SYNC, ADJ, R , RUN, SS Voltages..............................5V
T
Current into RUN Pin (Note 2)..................................1mA
V , AUX.................................................................25V
OUT
PIN CONFIGURATION
TOP VIEW
TOP VIEW
11
10
9
11
10
9
8
V
V
OUT
OUT
BANK 1
BANK 1
8
AUX
BIAS1
SS
RUN
BIAS2
ADJ
7
6
5
4
3
2
1
AUX
BIAS1
SS
RUN
BIAS2
ADJ
7
6
5
4
3
2
1
GND
GND
BANK 2
BANK 2
V
V
IN
IN
BANK 3
BANK 3
A
B
C
D
E
F G H J K L
A
B
C
D
E
F G H J K L
RT
SYNC
LGA PACKAGE
113-LEAD (15mm × 15mm × 4.32mm)
= 125°C, θ = 12.2°C/W, θ = 9.3°C/W,
RT
SYNC
BGA PACKAGE
113-LEAD (15mm × 15mm × 4.92mm)
= 125°C, θ = 12.2°C/W, θ = 9.3°C/W,
T
T
JMAX
JMAX
JA
JC(TOP)
JA
JC(TOP)
θ
= 3.6°C/W, θ
= 7.54°C/W
θ
= 3.6°C/W, θ
= 7.54°C/W
JC(BOTTOM)
JBOARD
JC(BOTTOM)
JBOARD
θ VALUES DETERMINED PER JESD 51-9
θ VALUES DETERMINED PER JESD 51-9
WEIGHT = 2.6 GRAMS
WEIGHT = 2.6 GRAMS
ORDER INFORMATION http://www.linear.com/product/LTM8027#orderinfo
PART NUMBER
PAD OR BALL FINISH
PART MARKING*
PACKAGE
TYPE
MSL
RATING
TEMPERATURE RANGE
(See Note 3)
DEVICE
FINISH CODE
LTM8027EV#PBF
LTM8027IV#PBF
LTM8027MPV#PBF
LTM8027EY#PBF
LTM8027IY#PBF
LTM8027IY
Au (RoHS)
LTM8027V
LTM8027V
LTM8027V
LTM8027Y
LTM8027Y
LTM8027Y
LTM8027Y
LTM8027Y
e4
e4
e4
e1
e1
e0
e1
e0
LGA
LGA
LGA
BGA
BGA
BGA
BGA
BGA
3
3
3
3
3
3
3
3
–40°C to 125°C
–40°C to 125°C
–55°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–55°C to 125°C
–55°C to 125°C
Au (RoHS)
Au (RoHS)
SAC305 (RoHS)
SAC305 (RoHS)
SnPb (63/37)
SAC305 (RoHS)
SnPb (63/37)
LTM8027MPY#PBF
LTM8027MPY
Consult Marketing for parts specified with wider operating temperature
ranges. *Device temperature grade is indicated by a label on the shipping
container. Pad or ball finish code is per IPC/JEDEC J-STD-609.
• Recommended LGA and BGA PCB Assembly and Manufacturing
Procedures:
www.linear.com/umodule/pcbassembly
• Pb-free and Non-Pb-free Part Markings:
www.linear.com/leadfree
• LGA and BGA Package and Tray Drawings:
www.linear.com/packaging
8027fd
2
For more information www.linear.com/LTM8027
LTM8027
ELECTRICAL CHARACTERISTICS The ldenotes the specifications which apply over the full internal operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 20V, BIAS1 = BIAS2 = 10V, RUN = 2V, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
l
V
V
Input DC Voltage
(Note 5)
4.5
60
V
V
IN
Maximum Output DC Voltage
Output DC Current
Minimum Start Voltage
Line Regulation
0A < I
≤ 4A, V = 48V
24
OUT
OUT
OUT
IN
I
V
IN
≤ 60V, V
= 12V, (Note 4)
0
4
A
OUT
V
7.5
V
IN(START)
V
V
= 12V, 15V< V < 60V, I
= 4A
≤ 4A
0.2
0.2
4.6
%
%
V
∆V /∆V
OUT
IN
LOAD
OUT
IN
Load Regulation
= 12V, V = 24V, 0A < I
∆V /∆I
OUT
IN
LOAD
OUT LOAD
UVLO(RISING)
V
V
V
Input Undervoltage Lockout Threshold
(Rising)
(Note 5)
Input Undervoltage Lockout Threshold
(Falling)
(Note 5)
3.7
V
UVLO(FALLING)
ADJ
ADJ Voltage
1.224
1.215
1.238
1.245
V
V
l
I
Quiescent Current into IN
V
BIAS
V
RUN
= V , V = 12VDC, No Load
AUX OUT
= 0V
39
9
mA
µA
Q(VIN)
V
BIAS1 Undervoltage Lockout (Rising)
BIAS1 Undervoltage Lockout (Falling)
6.5
6
V
V
BIAS1
BIAS1
I
Current into BIAS1
No Load
RUN = 0V
25
25
mA
µA
V
Minimum BIAS2 Voltage
3
1
V
µA
V
BIAS2
I
Current Into BIAS2
BIAS2
V
Minimum Voltage to Overdrive Internal
8.5
BIAS1(MINOV)
Regulator (INTV
)
CC
R
Internal Feedback Resistor
RUN Enable Voltage (Rising)
RUN Enable Voltage (Falling)
Switching Frequency
499
1.4
1.2
kΩ
V
FB
V
V
RUN(RISING)
RUN(FALLING)
V
f
R = 187kΩ
T
100
500
kHz
kHz
SW
T
R = 23.7kΩ
R
SYNC Input Resistance
SYNC Voltage Threshold
Soft-Start Charging Current
40
kΩ
V
SYNC
l
V
f
= 350kHz
2.3
SYNC(TH)
SYNC
I
2
µA
SS
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.
–40°C to 125°C internal operating temperature range. The LTM8027MP
is guaranteed to meet specifications over the full –55°C to 125°C
internal operating range. Note that the maximum internal temperature is
determined by specific operating conditions in conjunction with board
layout, the rated package thermal resistance and other environmental
factors.
Note 2: The RUN pin is internally clamped to 5V.
Note 3: The LTM8027E is guaranteed to meet performance specifications
from 0°C to 125°C internal operating temperature. Specifications over
the full –40°C to 125°C internal operating temperature range are assured
by design, characterization and correlation with statistical process
controls. The LTM8027I is guaranteed to meet specifications over the full
Note 4: The maximum continuous output current may be derated by the
LTM8027 junction temperature.
Note 5: V voltages below the start-up threshold (7.5V) are only
IN
supported when BIAS1 is externally driven above 6.5V.
8027fd
3
For more information www.linear.com/LTM8027
LTM8027
TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C unless otherwise noted)
Efficiency vs Load, VOUT = 2.5V
Efficiency vs Load, VOUT = 3.3V
Efficiency vs Load, VOUT = 5V
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
5V
IN
12V
24V
36V
48V
60V
IN
IN
IN
IN
IN
12V
24V
36V
48V
60V
IN
IN
IN
IN
IN
5V
IN
12V
24V
36V
IN
IN
IN
0
1
2
3
4
0
1
2
3
4
0
1
2
3
4
LOAD (A)
LOAD (A)
LOAD (A)
8027 G01
8027 G02
8027 G03
Efficiency vs Load, VOUT = 8V
Efficiency vs Load, VOUT = 12V
Efficiency vs Load, VOUT = 15V
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
12V
24V
36V
48V
60V
IN
IN
IN
IN
IN
24V
24V
IN
IN
IN
IN
IN
IN
IN
IN
36V
48V
60V
36V
48V
60V
0
1
2
3
4
0
1
2
3
4
0
1
2
3
4
LOAD (A)
LOAD (A)
LOAD (A)
8027 G04
8027 G05
8027 G06
Input Current
vs VIN Output Shorted
Efficiency vs Load, VOUT = 18V
Efficiency vs Load, VOUT = 24V
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
1.2
1.0
0.8
0.6
0.4
0.2
0
24V
IN
IN
IN
IN
36V
48V
60V
36V
48V
60V
IN
IN
IN
0
1
2
3
4
0
30
40
50
60
70
0
1
2
3
4
10
20
LOAD (A)
LOAD (A)
INPUT VOLTAGE (V)
8027 G07
8027 G09
8027 G08
8027fd
4
For more information www.linear.com/LTM8027
LTM8027
TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C unless otherwise noted)
Input Current vs Load,
VOUT = 2.5V
Input Current vs Load,
VOUT = 3.3V
Input Current vs Load,
VOUT = 5V
3000
2500
3500
3000
2500
2000
1800
1600
1400
1200
1000
800
5V
IN
5V
IN
12V
24V
36V
48V
60V
IN
IN
IN
IN
IN
12V
24V
36V
12V
24V
36V
48V
60V
IN
IN
IN
IN
IN
IN
IN
IN
2000
1500
2000
1500
1000
500
0
1000
500
0
600
400
200
0
1
2
4
0
1
2
3
3
3
4
0
3
0
1
2
3
4
LOAD (A)
LOAD (A)
LOAD (A)
8027 G10
8027 G11
8027 G12
Input Current vs Load,
Input Current vs Load,
VOUT = 12V
Input Current vs Load,
VOUT = 15V
V
OUT = 8V
3000
2500
3500
3000
2500
2500
2000
1500
1000
500
24V
IN
12V
24V
IN
IN
36V
IN
24V
36V
48V
60V
36V
IN
IN
IN
IN
IN
48V
IN
60V
IN
48V
IN
60V
IN
2000
1500
2000
1500
1000
500
0
1000
500
0
0
0
1
2
3
4
1
2
4
0
2
3
0
1
4
LOAD (A)
LOAD (A)
LOAD (A)
8027 G15
8027 G13
8027 G14
Input Current vs Load,
VOUT = 18V
Input Current vs Load,
VOUT = 24V
Bias Current vs Load,
VOUT = 2.5V
3500
3000
2500
2000
1500
1000
500
3500
3000
2500
2000
1500
1000
500
15.50
15.00
14.50
14.00
13.50
13.00
12.50
12.00
24V
36V
48V
60V
36V
48V
60V
IN
IN
IN
IN
IN
IN
IN
36V
24V
12V
IN
IN
IN
0
0
0
1
2
4
0
1
2
3
4
2
0
1
3
4
LOAD (A)
LOAD (A)
LOAD (A)
8027 G16
8027 G17
8027 G18
8027fd
5
For more information www.linear.com/LTM8027
LTM8027
TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C unless otherwise noted)
Bias Current vs Load,
VOUT = 3.3V
Bias Current vs Load,
VOUT = 5V
Bias Current vs Load,
VOUT = 8V
18.0
17.5
17.0
16.5
16.0
15.5
15.0
14.5
14.0
26.0
25.5
25.0
24.5
24.0
23.5
23.0
22.5
22.0
16.0
15.5
15.0
14.5
14.0
13.5
13.0
48V
36V
24V
12V
48V
36V
24V
12V
IN
IN
IN
IN
IN
IN
IN
IN
48V
36V
24V
IN
IN
IN
0
1
2
3
4
0
1
2
3
3
3
2
4
0
1
3
4
LOAD (A)
LOAD (A)
LOAD (A)
8027 G19
8027 G21
8027 G20
Bias Current vs Load,
VOUT = 12V
Bias Current vs Load,
VOUT = 15V
Bias Current vs Load,
VOUT = 18V
45
44
43
42
41
40
39
38
37
36
35
29.5
29.0
28.5
28.0
27.5
27.0
26.5
26.0
25.5
25.0
38
37
36
35
34
33
32
31
30
48V
36V
24V
48V
36V
24V
IN
IN
IN
IN
IN
IN
48V
IN
IN
36V
2
0
1
3
4
1
2
3
0
4
0
1
2
4
LOAD (A)
LOAD (A)
LOAD (A)
8027 G22
8027 G23
8027 G24
Bias Current vs Load,
VOUT = 24V
Minimum VIN vs Load,
VOUT = 5V
Minimum VIN vs Load,
VOUT = 8V
6.0
5.9
5.8
5.7
5.6
5.5
5.4
5.3
5.2
5.1
5.0
10.0
9.8
9.6
9.4
9.2
9.0
8.8
8.6
8.4
8.2
8.0
46
44
42
40
38
36
34
32
48V
IN
IN
36V
2
2
4
2
4
0
1
3
4
0
1
3
0
1
LOAD (A)
LOAD (A)
LOAD (A)
8027 G25
8027 G26
8027 G27
8027fd
6
For more information www.linear.com/LTM8027
LTM8027
TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C unless otherwise noted)
Minimum VIN vs Load,
VOUT = 12V
Minimum VIN vs Load,
VOUT = 15V
Minimum VIN vs Load,
VOUT = 18V
24
23
16.0
15.5
15.0
14.5
14.0
13.5
13.0
12.5
12.0
19.0
18.5
18.0
17.5
17.0
16.5
16.0
15.5
15.0
22
21
20
19
18
2
0
2
4
0
1
2
3
4
0
1
3
3
3
4
1
3
LOAD (A)
LOAD (A)
LOAD (A)
8027 G28
8027 G29
8027 G30
Minimum VIN vs Load,
VOUT = 24V
Minimum VIN vs VOUT
,
Minimum VIN vs Load,
VOUT = –3.3V
IOUT = 4A
32
30
28
35
30
9
8
7
6
5
4
3
2
1
0
25
20
15
10
5
26
24
22
20
18
0
1
2
4
5
10
15
(V)
25
0
0
20
2
0
1
3
4
LOAD (A)
V
OUT
LOAD (A)
8027 G31
8027 G32
8027 G33
Minimum VIN vs Load,
VOUT = –5V
Minimum VIN vs Load,
VOUT = –8V
Minimum VIN vs Load,
VOUT = –12V
12
10
30
25
50
45
40
35
30
25
20
15
10
5
8
6
20
15
4
2
0
10
5
0
0
0
1
2
4
0
1
2
3
4
0
1
2
3
4
LOAD (A)
LOAD (A)
LOAD (A)
8027 G34
8027 G35
8027 G36
8027fd
7
For more information www.linear.com/LTM8027
LTM8027
TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C unless otherwise noted)
Temperature Rise vs Load,
VOUT = 2.5V
Temperature Rise vs Load,
VOUT = 3.3V
Temperature Rise vs Load,
VOUT = 5V
50
45
40
35
30
25
20
15
10
5
42
37
32
27
22
17
12
7
45
40
35
30
25
20
15
10
5
60V
IN
60V
IN
36V
IN
48V
IN
48V
IN
24V
IN
36V
IN
36V
IN
12V
IN
24V
IN
24V
IN
5V
IN
12V
IN
12V
IN
IN
5V
0
2
0
2
2
4
0
1
3
4
2
0
1
3
0
1
3
4
LOAD (A)
LOAD (A)
LOAD (A)
8027 G37
8027 G39
8027 G38
Temperature Rise vs Load,
VOUT = 8V
Temperature Rise vs Load,
VOUT = 12V
Temperature Rise vs Load,
VOUT = 15V
70
60
50
80
70
60
50
40
30
20
10
0
90
80
70
60
50
40
30
20
10
0
60V
IN
60V
IN
60V
IN
48V
IN
48V
IN
48V
IN
36V
IN
36V
IN
36V
IN
24V
IN
24V
IN
24V
IN
12V
IN
20.5V
IN
16V
IN
40
30
20
10
0
1
2
4
0
3
2
2
0
1
3
4
0
1
3
4
LOAD (A)
LOAD (A)
LOAD (A)
8027 G40
8027 G41
8027 G42
Temperature Rise vs Load,
VOUT = 18V
Temperature Rise vs Load,
VOUT = 24V
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
60V
IN
60V
IN
48V
IN
48V
IN
36V
36V
IN
IN
26V
IN
0
1
2
3
4
0
1
2
3
4
LOAD (A)
LOAD (A)
8027 G43
8027 G44
8027fd
8
For more information www.linear.com/LTM8027
LTM8027
PIN FUNCTIONS
GND (Bank 2): Tie these GND pins to a local ground plane
below the LTM8027 and the circuit components.
PACKAGE ROW AND COLUMN LABELING MAY VARY
AMONG µModule PRODUCTS. REVIEW EACH PACKAGE
LAYOUT CAREFULLY.
RT (Pin B1): The RT pin is used to program the switching
frequency of the LTM8027 by connecting a resistor from
thispintoground.TheApplicationsInformationsectionof
the data sheet includes a table to determine the resistance
value based on the desired switching frequency. Minimize
capacitance at this pin.
V (Bank3):TheV pinssupplycurrenttotheLTM8027’s
IN
IN
internal regulator and to the internal power switch. These
pins must be locally bypassed with an external, low ESR
capacitor (see Table 2).
V
(Bank 1): Power Output Pins. Apply the output
OUT
filter capacitor and the output load between these and
SYNC (Pin C1): The SYNC pin provides an external clock
the GND pins.
input for synchronization of the internal oscillator. The
R resistor should be set such that the internal oscillator
T
AUX (Pin A7): Low Current Voltage Source for BIAS1
and BIAS2. In many designs, the BIAS pin is connected
frequency is 10% to 25% below the external clock fre-
quency. This external clock frequency must be between
100kHz and 500kHz. If unused, tie the SYNC pin to GND.
FormoreinformationseeOscillatorSyncintheApplication
Information section of this data sheet.
to V
by way of the AUX pin. The AUX pin is internally
OUT
connectedtoV
andisplacedneartheBIASpinstoease
OUT
printedcircuitboardrouting.Althoughthispinisinternally
connected to V , do NOT connect this pin to the load. If
OUT
this pin is not tied to BIAS1 and BIAS2, leave it floating.
ADJ(PinA2):TheLTM8027regulatesitsADJpinto1.23V.
Connect the adjust resistor from this pin to ground. The
BIAS1 (Pin A6): The BIAS1 pin connects to the internal
power bus. Connect to a power source greater than 8.5V.
If the output is greater than 8.5V, connect it to this pin. If
the output voltage is less, connect this to a voltage source
between 8.5V and 15V.
value of R
is given by the equation:
ADJ
R
ADJ
= 613.77/(V
– 1.23)
OUT
where R
is in kΩ.
ADJ
SS (Pin A5): The soft-start pin is used to program the
BIAS2 (Pin A3): Internal Biasing Power. Connect to AUX
(if 24V or less) or a voltage source above 3V. Do not leave
BIAS2 floating.
supply soft-start function. Use the following formula to
calculate C for a given output voltage slew rate:
SS
C
SS
= 2µA(t /1.231V)
SS
RUN (Pin A4): Tie the RUN pin to ground to shut down
the LTM8027. Tie to 1.4V or more for normal operation.
The RUN pin is internally clamped to 5V, so when it is
pulled up, be sure to use a pull-up resistor that limits the
current into the RUN pin to less than 1mA. If the shutdown
The pin should be left unconnected when not using the
soft-start function.
feature is not used, tie this pin to the V pin through a
IN
pull-up resistor.
8027fd
9
For more information www.linear.com/LTM8027
LTM8027
BLOCK DIAGRAM
V
V
OUT
6.8µH
4.7pF
IN
499k
2.2µF
RUN
SS
AUX
INTERNAL
CURRENT
MODE
CONTROLLER
CONNECTION
TO V
OUT
SYNC
BIAS1
BIAS2
INTERNAL
LINEAR
REGULATOR
INTV
CC
V
IN
GND
R
T
ADJ
8027 BD
OPERATION
The LTM8027 is a standalone nonisolated step-down
switchingDC/DCpowersupplywithaninputvoltagerange
of 4.5V to 60V that can deliver up to 4A of output current.
This module provides a precisely regulated output volt-
age up to 24V, programmable via one external resistor.
Given that the LTM8027 is a step-down converter, make
sure that the input voltage is high enough to support the
desiredoutputvoltageandloadcurrent. Asimplifiedblock
diagram is given above. The LTM8027 contains a current
mode controller, power switching element, power induc-
tor, power MOSFETs and a modest amount of input and
output capacitance.
The LTM8027 is a fixed frequency PWM regulator. The
switching frequency is set by simply connecting the ap-
propriate resistor from the RT pin to GND.
A linear regulator provides internal power (shown as
INTV on the Block Diagram) to the control circuitry.
CC
The bias regulator normally draws power from the V
IN
pin, but if the BIAS1 pin is connected to an external volt-
age higher than 8.5V, bias power will be drawn from the
external source (typically the regulated output voltage).
This improves efficiency. The RUN pin is used to enable
or place the LTM8027 in shutdown, disconnecting the
output and reducing the input current to less than 9µA.
8027fd
10
For more information www.linear.com/LTM8027
LTM8027
APPLICATIONS INFORMATION
For most applications, the design process is straight
forward, summarized as follows:
input voltage can ring to twice its nominal value, possi-
bly exceeding the device’s rating. This situation is easily
avoided; see the Hot-Plugging Safely section.
1. Look at Table 2 and find the row that has the desired
input range and output voltage.
Input Power Requirements
2. Apply the recommended C , C , R and R values.
IN OUT ADJ
T
The LTM8027 is biased using an internal linear regulator
to generate operational voltages from the V pin. Virtually
3. Connect the BIAS pins as indicated.
IN
allofthecircuitryintheLTM8027isbiasedviathisinternal
Whilethesecomponentandconnectioncombinationshave
been tested for proper operation, it is incumbent upon the
user to verify proper operation over the intended system’s
line, load and environmental conditions.
linear regulator output (INTV on the Block Diagram).
CC
This pin is internally decoupled with a low ESR capacitor
to GND. The INTV regulator generates an 8V output
CC
provided there is ample voltage on the V pin. The INTV
IN
CC
regulator has approximately 1V of dropout, and will follow
the V pin with voltages below the dropout threshold.
Capacitor Selection Considerations
IN
The C and C
capacitor values in Table 2 are the
IN
OUT
The LTM8027 has a typical start-up requirement of V >
IN
minimum recommended values for the associated oper-
ating conditions. Applying capacitor values below those
indicated in Table 2 is not recommended, and may result
in undesirable operation. Using larger values is generally
acceptable, and can yield improved dynamic response, if
it is necessary. Again, it is incumbent upon the user to
verify proper operation over the intended system’s line,
load and environmental conditions.
7.5V. This assures that the onboard regulator has ample
headroom to bring the internal regulator (INTV ) above
CC
its UVLO threshold. The INTV regulator can only source
CC
current, so forcing the BIAS1 pin above 8.5V allows use
of externally derived power for the IC. This effectively
shuts down the internal linear regulator and reduces
powerdissipationwithintheLTM8027. Usingtheonboard
regulator for start-up, then applying power to BIAS1 from
the converter output or external supply maximizes con-
version efficiencies and is a common practice. If BIAS1
is maintained above 6.5V using an external source, the
Ceramic capacitors are small, robust and have very low
ESR. However, not all ceramic capacitors are suitable.
X5R and X7R types are stable over temperature and ap-
plied voltage and give dependable service. Other types,
including Y5V and Z5U have very large temperature and
voltage coefficients of capacitance. In an application cir-
cuit they may have only a small fraction of their nominal
capacitanceresultinginmuchhigheroutputvoltageripple
than expected.
LTM8027 can continue to operate with V as low as 4.5V.
IN
BIAS Power
The internal circuitry of the LTM8027 is powered by the
INTV bus, which is derived either from the afore men-
CC
tioned internal linear regulator or the BIAS1 pin, if it is
A final precaution regarding ceramic capacitors concerns
the maximum input voltage rating of the LTM8027. A
ceramic input capacitor combined with trace or cable
inductance forms a high Q (under damped) tank circuit.
If the LTM8027 circuit is plugged into a live supply, the
greater than 8.5V. Since the internal linear regulator is
by nature dissipative, deriving INTV from an external
CC
sourcethroughtheBIASpinsreducesthepowerlostwithin
the LTM8027 and can increase overall system efficiency.
8027fd
11
For more information www.linear.com/LTM8027
LTM8027
APPLICATIONS INFORMATION
For example, suppose the LTM8027 needs to provide
ing SS pin voltage, reducing the output voltage overshoot
during a short-circuit recovery.
5V from an input voltage source that is nominally 12V.
From Table 2, the recommended R value is 75k, which
T
The desired soft-start time (t ) is programmed via the
SS
corresponds to an operating frequency of 210kHz. From
C
SS
capacitor as follows:
the graphs in the Typical Performance Characteristics, the
2µA • tSS
1.231V
typical internal regulator (INTV ) current at 12V and
CC
IN
CSS
=
210kHz is 15mA. The power dissipated by the internal
linear regulator at 12V is given by the equation:
IN
The amount of time in which the power supply must be
P
= (V – 8) • I
IN INTVCC
INTVCC
under a V , internal regulator (INTV ) or V
UVLO
IN
CC
SHDN
fault condition (t
) before the SS pin voltage enters
or only 60mW. This has a small but probably acceptable
effect on the operating temperature of the LTM8027.
FAULT
its active region is approximated by the following formula:
CSS • 0.65V
If the input rises to 60V, however, the power dissipation
is a lot higher, over 780mW. This can cause unnecessarily
tFAULT
=
50µA
high junction temperatures if the INTV regulator must
CC
dissipate this amount of power for very long.
Operating Frequency Trade-offs
Connect BIAS2 to AUX (if 24V or less) or a voltage source
above 3V.
The LTM8027 uses a constant frequency architecture that
can be programmed over a 100kHz to 500kHz range with
a single resistor from the RT pin to ground. The nominal
voltage on the RT pin is 1V and the current that flows from
this pin is used to charge an internal oscillator capacitor.
Soft-Start
The soft-start function controls the slew rate of the power
supply output voltage during start-up. A controlled output
voltagerampminimizesoutputvoltageovershoot,reduces
The value of R for a given operating frequency can be
T
chosen from Figure 1 or Table 1.
inrush current from the V supply, and facilitates supply
IN
sequencing.AcapacitorconnectedfromtheSSpintoGND
programs the slew rate. The capacitor is charged from an
internal 2µA current source producing a ramped voltage
that overrides the command reference to the controller,
resulting in a smooth output voltage ramp. The soft-start
circuitisdisabledoncetheSSpinvoltagehasbeencharged
to 200mV above the internal reference of 1.231V.
600
500
400
300
200
100
0
DuringaV UVLO,RUNevent,orundervoltageoninternal
IN
bias, the SS pin voltage is discharged with a 50µA current.
Therefore, the value of the SS capacitor determines how
long one of these events must be in order to completely
discharge the soft-start capacitor. In the case of an output
overload or short circuit, the SS pin voltage is clamped to
a diode drop above the ADJ pin. Once the short has been
0
50
100
(kΩ)
150
200
R
T
8027 F01
Figure 1. Timing Resistor (RT) Value
removed the V
pin voltage starts to recover. The soft-
ADJ
start circuit takes control of the output voltage slew rate
once the V
pin voltage has exceeded the slowly ramp-
ADJ
8027fd
12
For more information www.linear.com/LTM8027
LTM8027
APPLICATIONS INFORMATION
Table 1 lists typical resistor values for common operating
frequencies.
RUN Control
The LTM8027 RUN pin uses a reference threshold of 1.4V.
This precision threshold allows use of the RUN pin for both
logic-levelcontrolledapplicationsandanalogmonitoringap-
plications such aspower supply sequencing. TheLTM8027
operational status is primarily controlled by a UVLO circuit
on internal power source. When the LTM8027 is enabled
Table 1. RT Resistor Values vs Frequency
R (kΩ)
T
f
(kHz)
SW
187
118
100
150
200
250
300
350
400
450
500
82.5
via the RUN pin, only the internal regulator (INTV ) is en-
CC
63.4k
48.7k
40.2k
31.6k
27.4k
23.7k
abled.SwitchingremainsdisableduntiltheUVLOthreshold
is achieved at the BIAS1 pin, when the remainder of the
LTM8027 is enabled and switching commences.
Because the LTM8027 high power converter is a power
transfer device, a voltage that is lower than expected on
the input supply could require currents that exceed the
sourcing capabilities of that supply, causing the system
to lock up in an undervoltage state. Input supply start-
up protection can be achieved by enabling the RUN pin
It is recommended that the user apply the R value given
T
in Table 2 for the input and output operating condition.
Systemlevelorotherconsiderations,however,mayneces-
sitate another operating frequency. While the LTM8027 is
flexible enough to accommodate a wide range of operat-
ing frequencies, a haphazardly chosen one may result
in undesirable operation under certain operating or fault
conditions. A frequency that is too high can damage the
LTM8027 if the output is overloaded or short-circuited. A
frequencythatistoolowcanresultinafinaldesignthathas
too much output ripple or too large of an output capacitor.
using a resistive divider from the V supply to ground.
IN
Setting the divider output to 1.4V when that supply is at
an adequate voltage prevents an LTM8027 converter from
drawing large currents until the input supply is able to
provide the required power. 200mV of input hysteresis on
the RUN pin allows for about 15% of input supply droop
before disabling the converter.
Input UVLO and RUN
The maximum frequency (f
) at which the LTM8027
MAX
should be allowed to switch and the minimum frequency
set resistor value that should be used for a given set of
input and output operating condition is given in Table 2
The RUN pin has a precision voltage threshold with hys-
teresis which can be used as an undervoltage lockout
threshold (UVLO) for the power supply. Undervoltage
lockout keeps the LTM8027 in shutdown until the supply
input voltage is above a certain voltage programmed by
theuser.Thehysteresisvoltagepreventsnoisefromfalsely
as R
. There are additional conditions that must be
T(MIN)
satisfied if the synchronization function is used. Please
refer to the Synchronization section for details.
tripping UVLO. Resistors are chosen by first selecting R
(refer to Figure 2). Then:
B
Output Voltage Programming
The LTM8027 regulates its ADJ pin to 1.23V. Connect the
V
⎛
⎞
IN(ON)
RA =RB •
–1
⎟
adjust resistor from this pin to ground. The value of R
ADJ
– 1.23),
⎜
1.4V
⎝
⎠
is given by the equation R
= 613.77/(V
ADJ
OUT
where R
is in kΩ.
ADJ
where V
is the input voltage at which the undervolt-
age lockout is disabled and the supply turns on.
IN(ON)
8027fd
13
For more information www.linear.com/LTM8027
LTM8027
APPLICATIONS INFORMATION
V
SUPPLY
complete discussion). The low loss ceramic capacitor
combined with stray inductance in series with the power
source forms an under damped tank circuit, and the volt-
R
A
RUN PIN
age at the V pin of the LTM8027 can ring to twice the
IN
R
B
nominal input voltage, possibly exceeding the LTM8027’s
rating and damaging the part. If the input supply is poorly
controlledortheuserwillbepluggingtheLTM8027intoan
energizedsupply, theinputnetworkshouldbedesignedto
prevent this overshoot by introducing a damping element
into the path of current flow. This is often done by add-
ing an inexpensive electrolytic bulk capacitor across the
input terminals of the LTM8027. The criteria for selecting
this capacitor is that the ESR is high enough to damp the
ringing, and the capacitance value is several times larger
than the LTM8027 ceramic input capacitor. The bulk
capacitor does not need to be located physically close to
the LTM8027; it should be located close to the application
board’s input connector instead.
8027 F02
Figure 2. Undervoltage Lockout Resistive Divider
Example: Select R = 49.9k, V
= 14.5V (based upon
IN(ON)
B
a 15V minimum input voltage)
14.5V
1.4V
⎛
⎞
⎠
R = 49.9k •
–1 = 464k
⎟
⎜
⎝
A
The V turn off voltage is 15% below turn on. In the
IN
example the V
would be 12.3V. The shutdown func-
IN(OFF)
tion can be disabled by connecting the RUN pin to the V
IN
pin through a large value pull-up resistor, (R ). This pin
PU
contains a low impedance clamp at 6V, so the RUN pin
Synchronization
will sink current from the R pull-up resistor:
PU
The oscillator can be synchronized to an external clock.
V – 6V
RPU
IN
ChoosetheR resistorsuchthattheresultantfrequencyis
T
IRUN
=
atleast10%belowthedesiredsynchronizationfrequency.
It is recommended that the SYNC pin be driven with a
square wave that has amplitude greater than 2.3V, pulse
width greater than 1µs and rise time less than 500ns. The
rising edge of the sync wave form triggers the discharge
of the internal oscillator capacitor.
Because this arrangement will clamp the RUN pin to
6V, it will violate the 5V absolute maximum voltage
rating of the pin. This is permitted, however, as long
as the absolute maximum input current rating of 1mA
is not exceeded. Input RUN pin currents of <100µA
are recommended: a 1M or greater pull-up resistor is
typically used for this configuration.
PCB Layout
Most of the headaches associated with PCB layout have
been alleviated or even eliminated by the high level of
integration of the LTM8027. The LTM8027 is neverthe-
less a switching power supply, and care must be taken to
minimize EMI and ensure proper operation. Even with the
high level of integration, you may fail to achieve specified
operation with a haphazard or poor layout. See Figure 3
for a suggested layout.
Hot-Plugging Safely
The small size, robustness and low impedance of ceramic
capacitors make them an attractive option for the input
bypass capacitor of LTM8027. However, these capacitors
can cause problems if the LTM8027 is plugged into a live
supply (see Linear Technology Application Note 88 for a
8027fd
14
For more information www.linear.com/LTM8027
LTM8027
APPLICATIONS INFORMATION
V
OUT
C
OUT
C
OUT
GND
AUX
BIAS1
SS
RUN
C
IN
V
BIAS2
IN
R
ADJ
R
T
GND
8027 F03
SYNC
Figure 3. Suggested Layout
Figure 3. The LTM8027 can benefit from the heat sinking
afforded by vias that connect to internal GND planes at
these locations, due to their proximity to internal power
handling components. The optimum number of thermal
vias depends upon the printed circuit board design.
For example, a board might use very small via holes.
It should employ more thermal vias than a board that
uses larger holes.
Ensurethatthegroundingandheatsinkingareacceptable.
A few rules to keep in mind are:
1. Place the R and R resistors as close as possible to
ADJ
T
their respective pins.
2. Place the C capacitor as close as possible to the V
IN
IN
and GND connection of the LTM8027.
3. Place the C
capacitor as close as possible to the
OUT
V
and GND connection of the LTM8027.
OUT
Thermal Considerations
4. Place the C and C
capacitors such that their
OUT
IN
The LTM8027 output current may need to be derated if
it is required to operate in a high ambient temperature or
deliver a large amount of continuous power. The amount
of current derating is dependent upon the input voltage,
output power and ambient temperature. The temperature
rise curves given in the Typical Performance Character-
istics section can be used as a guide. These curves were
ground current flow directly adjacent to or underneath
the LTM8027.
5. Connect all of the GND connections to as large a copper
pour or plane area as possible on the top layer. Avoid
breaking the ground connection between the external
components and the LTM8027.
2
generated by a LTM8027 mounted to a 58cm 4-layer FR4
Use vias to connect the GND copper area to the board’s
internalgroundplanes. LiberallydistributetheseGNDvias
to provide both a good ground connection and thermal
path to the internal planes of the printed circuit board. Pay
attention to the location and density of the thermal vias in
printedcircuitboard. Boardsofothersizesandlayercount
can exhibit different thermal behavior, so it is incumbent
upon the user to verify proper operation over the intended
system’sline,loadandenvironmentaloperatingconditions.
8027fd
15
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LTM8027
APPLICATIONS INFORMATION
The die temperature of the LTM8027 must be lower than
the maximum rating of 125°C, so care should be taken
in the layout of the circuit to ensure good heat sinking
of the LTM8027. The bulk of the heat flow out of the
LTM8027 is through the bottom of the module and the
LGA pads into the printed circuit board. Consequently a
poor printed circuit board design can cause excessive
heating, resulting in impaired performance or reliability.
Please refer to the PCB Layout section for printed circuit
board design suggestions.
The junction-to-air and junction-to-board thermal resis-
tances given in the Pin Configuration diagram may also
be used to estimate the LTM8027 internal temperature.
These thermal coefficients are determined per JESD 51-9
(JEDECstandard,testboardsforareaarraysurfacemount
package thermal measurements) through analysis and
physical correlation. Bear in mind that the actual thermal
resistance of the LTM8027 to the printed circuit board
depends upon the design of the circuit board.
Table 2. Recommended Component Values and Configuration
(TA = 25°C. See Typical Performance Characteristics for load Conditions)
V
RANGE
(V)
V
R
f
R
f
R
MAX
IN
OUT
ADJ
OPTIMAL
OPTIMAL
MAX
(V)
3.3
5
C
C
BIAS1
8.5V to 15V
8.5V to 15V
8.5V to 15V
AUX
(kΩ)
(kHz)
(kΩ)
(kHz)
160
230
350
500
500
500
500
(kΩ)
IN
OUT
4.5 to 60
7.5 to 60
10.5 to 60
16 to 60
20.5 to 60
26 to 60
34 to 60
301
115
210
260
300
350
400
430
154
75.0
59.0
48.7
40.2
31.6
28.7
107
2 × 4.7µF 2220 100V 5 × 100µF 1812 6.3V
2 × 4.7µF 2220 100V 4 × 100µF 1210 6.3V
2 × 4.7µF 2220 100V 4 × 47µF 1210 10V
2 × 4.7µF 2220 100V 4 × 22µF 1210 16V
2 × 4.7µF 2220 100V 4 × 22µF 1210 16V
2 × 4.7µF 2220 100V 4 × 10µF 1812 25V
2 × 4.7µF 2220 100V 4 × 10µF 1812 25V
162
68.2
40.2
23.7
23.7
23.7
23.7
8
90.9
56.2
44.2
36.5
26.7
12
15
18
24
AUX
8.5V to 15V
8.5V to 15V
4.5 to 40
4.5 to 40
7.5 to 40
10.5 to 40
16 to 40
20.5 to 40
26 to 40
34 to 40
2.5
3.3
5
8.5V to 15V
8.5V to 15V
8.5V to 15V
8.5V to 15V
AUX
487
301
145
165
210
260
300
350
400
430
124
102
185
240
315
500
500
500
500
500
88.7
64.9
45.3
23.7
23.7
23.7
23.7
23.7
2 × 10µF 2220 50V 5 × 100µF 1812 6.3V
2 × 10µF 2220 50V 4 × 100µF 1812 6.3V
2 × 10µF 2220 50V 4 × 100µF 1210 6.3V
2 × 10µF 2220 50V 4 × 47µF 1210 10V
2 × 10µF 2220 50V 4 × 22µF 1210 16V
1 × 10µF 2220 50V 4 × 22µF 1210 16V
1 × 10µF 2220 50V 4 × 10µF 1812 25V
1 × 10µF 2220 50V 4 × 10µF 1812 25V
162
75.0
59.0
48.7
40.2
31.6
28.7
8
90.9
56.2
44.2
36.5
26.7
12
15
18
24
AUX
8.5V to 15V
8.5V to 15V
4.5 to 56
4.5 to 55
10.5 to 52
16 to 48
–3.3
–5
8.5V to 15V Above Output
8.5V to 15V Above Output
8.5V to 15V Above Output
AUX
301
162
115
190
260
300
154
90.9
59.0
48.7
155
230
350
500
115
68.2
40.2
23.7
2 × 4.7µF 2220 100V 5 × 100µF 1812 6.3V
2 × 4.7µF 2220 100V 4 × 100µF 1210 6.3V
2 × 4.7µF 2220 100V 4 × 47µF 1210 10V
2 × 4.7µF 2220 100V 4 × 22µF 1210 16V
–8
90.9
56.2
–12
8027fd
16
For more information www.linear.com/LTM8027
LTM8027
TYPICAL APPLICATIONS
3.3V VOUT Step-Down Converter
5V VOUT Step-Down Converter
V
3.3V
4A
V
5V
4A
OUT
OUT
V
*
V
IN
IN
V
V
V
V
OUT
IN
OUT
IN
4.5V TO 40V
7.5V TO 60V
10µF
×2
4.7µF
×2
1M
1M
LTM8027
LTM8027
9V
RUN
SS
BIAS1
BIAS2
AUX
9V
RUN
SS
BIAS1
BIAS2
AUX
100µF
×4
100µF
×4
SYNC
RT
SYNC
RT
ADJ
ADJ
GND
GND
102k
301k
75k
162k
*RUNNING VOLTAGE. SEE APPLICATIONS
INFORMATION FOR START-UP DETAILS
3845 TA02
3845 TA03
18V VOUT Step-Down Converter
–12V VOUT Positive-to-Negative Converter
V
OUT
V
IN
V
18V
IN
V
IN
V
OUT
V
IN
V
OUT
20V TO 48V
26V TO 60V
3A
4A SURGE
4.7µF
×2
4.7µF
×2
1M
LTM8027
1M
LTM8027
RUN
SS
BIAS1
BIAS2
AUX
9V
RUN
SS
BIAS1
BIAS2
AUX
SCHOTTKY
22µF
×4
10µF
×4
DIODE
SYNC
RT
SYNC
RT
OPTIONAL
ADJ
ADJ
GND
GND
56.2k
48.7k
31.6k
36.5k
V
–12V
3A
OUT
3845 TA07
3845 TA05
PACKAGE PHOTOGRAPHS
LGA
BGA
8027fd
17
For more information www.linear.com/LTM8027
LTM8027
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/product/LTM8027#packaging for the most recent package drawings.
Z
/ / b b b
Z
6 . 3 5 0
5 . 0 8 0
3 . 8 1 0
2 . 5 4 0
1 . 2 7 0
0 . 0 0 0
1 . 2 7 0
2 . 5 4 0
3 . 8 1 0
5 . 0 8 0
6 . 3 5 0
8027fd
18
For more information www.linear.com/LTM8027
LTM8027
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/product/LTM8027#packaging for the most recent package drawings.
Z
/ / b b b
Z
6 . 3 5 0
5 . 0 8 0
3 . 8 1 0
2 . 5 4 0
1 . 2 7 0
0 . 0 0 0
1 . 2 7 0
2 . 5 4 0
3 . 8 1 0
5 . 0 8 0
6 . 3 5 0
a a a
Z
8027fd
19
For more information www.linear.com/LTM8027
LTM8027
PACKAGE DESCRIPTION
Pin Assignment Table
(Arranged by Pin Number)
PIN NAME
PIN NAME
PIN NAME
GND
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
B1
B2
B3
B4
B5
B6
B7
B8
B9
B10
B11
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C11
D1
D2
D3
D4
D5
GND
ADJ
D6
D7
D8
D9
D10
D11
E1
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
H5
H6
H7
H8
H9
H10
H11
J1
GND
BIAS2
RUN
SS
GND
GND
V
V
V
V
V
V
OUT
OUT
OUT
IN
BIAS1
AUX
GND
GND
GND
GND
RT
E2
E3
J2
IN
E4
J3
IN
E5
J5
GND
GND
GND
GND
E6
J6
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
SYNC
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
E7
J7
E8
J8
E9
V
OUT
V
OUT
V
OUT
J9
V
V
V
V
V
V
OUT
OUT
OUT
IN
E10
E11
F1
J10
J11
K1
K2
K3
K5
K6
K7
K8
K9
K10
K11
L1
GND
GND
GND
GND
GND
GND
GND
GND
F2
IN
F3
IN
F4
GND
GND
GND
GND
F5
F6
F7
F8
V
V
V
V
V
V
OUT
OUT
OUT
IN
F9
V
V
V
OUT
OUT
OUT
F10
F11
G5
G6
G7
G8
G9
G10
G11
H1
H2
H3
GND
GND
GND
GND
L2
IN
L3
IN
L5
GND
GND
GND
GND
L6
V
V
V
V
V
V
L7
OUT
OUT
OUT
IN
L8
L9
V
V
V
OUT
OUT
OUT
L10
L11
IN
IN
8027fd
20
For more information www.linear.com/LTM8027
LTM8027
REVISION HISTORY
REV
DATE
DESCRIPTION
PAGE NUMBER
A
1/11
Changed Shutdown Current Supply to 9µA in Features.
Updated Absolute Maximum Ratings section.
1
2
Updated V
and Note 3 in Electrical Characteristics section.
3
BIAS1(MINOV)
Replaced graph 9.
4
Updated Pin Functions section.
9
Text edits to Applications Information.
Updated Typical Applications.
11-16
17, 18
22
2
Updated Related Parts.
B
9/11
Added (Note 3) notation to the Order Information section.
Updated minimum spec for V
.
3
BIAS2
Updated descriptions for AUX and BIAS2 in the Pin Functions section.
Updated text in the Input Power Requirements section.
Added text to end of the BIAS Power section.
9
11
12
1, 2
9
C
D
05/14 Add BGA package option
Add advisory notice
Add BGA package drawing
19
12
22
12/16 Corrected R value from 162k to 75k
T
Updated Related Parts
8027fd
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
21
LTM8027
TYPICAL APPLICATION
15V VOUT Step-Down Converter
V
OUT
V
15V
IN
V
IN
V
OUT
20.5V TO 60V
3.5A
4A SURGE
4.7µF
×2
1M
LTM8027
RUN
SS
BIAS1
BIAS2
AUX
22µF
×4
SYNC
RT
ADJ
GND
40.2k
44.2k
3845 TA04
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTM8050
2A, 58V DC/DC µModule Regulator
3.6V ≤ V ≤ 58V, 0.8V ≤ V
≤ 24V, Synchronizable, Parallelable, 9mm ×
IN
OUT
15mm × 4.92mm BGA
LTM4601/
LTM4601A
12A DC/DC µModule Regulator with PLL, Output
Tracking/Margining and Remote Sensing
Synchronizable, PolyPhase Operation, LTM4601-1 Version has no Remote
Sensing
LTM4603
6A DC/DC µModule with PLL and Output Tracking/ Synchronizable, PolyPhase Operation, LTM4603-1 Version has no Remote
Margining and Remote Sensing
Sensing, Pin Compatible with the LTM4601
LTM4604A
LTM4608A
LTM8020
LTM8022
4A Low V DC/DC µModule Regulator
2.375V ≤ V ≤ 5V, 0.8V ≤ V
≤ 5V, 9mm × 15mm × 2.3mm LGA
IN
IN
OUT
8A Low V DC/DC µModule Regulator
2.7V ≤ V ≤ 5V, 0.6V ≤ V
≤ 5V, 9mm × 15mm × 2.8mm LGA
IN
IN
OUT
200mA, 36V DC/DC µModule Regulator
1A, 36V DC/DC µModule Regulator
Fixed 450kHz Frequency, 1.25V ≤ V
≤ 5V, 6.25mm × 6.25mm × 2.32mm LGA
OUT
Adjustable Frequency, 0.8V ≤ V
Pin Compatible to the LTM8023
≤ 5V, 9mm × 11.25mm × 2.82mm LGA,
OUT
LTM8023
2A, 36V DC/DC µModule Regulator
Adjustable Frequency, 0.8V ≤ V
≤ 5V, 9mm × 11.25mm × 2.82mm LGA,
OUT
Pin Compatible to the LTM8022
LTM8025
LTM4624
3A, 36V DC/DC µModule Regulator
0.8V ≤ V ≤ 24V, 9mm × 15mm × 4.32mm LGA
OUT
14V , 4A, Step-Down µModule Regulator in Tiny 4V ≤ V ≤ 14V, 0.6V ≤ V
≤ 5.5V, V
Tracking, PGOOD, Light Load Mode,
IN
IN
OUT
OUT
2
6.25mm × 6.25mm × 5.01mm BGA
Complete Solution in 1cm (Single Sided PCB)
≤ 5.5V, CLK Input and Output, V
LTM4644
Quad 4A, 14V Step-Down µModule Regulator with 4V ≤ V ≤ 14V, 0.6V ≤ V
Configurable Output Array
Tracking,
OUT
IN
OUT
PGOOD, 9mm × 15mm × 5.01mm BGA
LTM8064
LTM8056
LTM8053
58V , 6A C
Step-Down μModule Regulator
Buck-Boost μModule Regulator
6V ≤ V ≤ 58V, 1.2V ≤ V
≤ 36V, 16mm × 11.9mm × 4.92mm BGA Package
≤ 48V, 15mm × 15mm × 4.92mm BGA Package
IN
VCC
IN
OUT
58V , 48 V
5V ≤ V ≤ 58V, 1.2V ≤ V
IN
IN
OUT
OUT
40V , 3.5A Step-Down μModule Regulator
3.4V ≤ V ≤ 40V, 0.97V ≤ V
≤ 15V, 6.25mm × 9mm × 3.32mm BGA Package
IN
IN
OUT
8027fd
LT 1216 REV D • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
22
(408)432-1900 FAX: (408) 434-0507 www.linear.com/LTM8027
●
●
LINEAR TECHNOLOGY CORPORATION 2009
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