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LTM8027IV [Linear]

60V, 4A DC/DC Module Regulator; 60V ， 4A DC / DC模块稳压器
LTM8027IV
型号： LTM8027IV
厂家： Linear    Linear
描述：

60V, 4A DC/DC Module Regulator
60V ， 4A DC / DC模块稳压器

稳压器
文件： 总20页 (文件大小：246K)
中文：  中文翻译
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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, power switches, inductor and all support components.  
Operatingoveraninputvoltagerangeof4.5Vto60V(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  
10μA 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
Pb-Free (e4) RoHS Compliant Package with  
Gold Pad Finish  
n
Tiny, Low Profile (15mm × 15mm × 4.32mm)  
TheLTM8027ispackagedinathermallyenhanced,compact  
(15mm × 15mm) and low profile (4.32mm) over-molded  
land grid array (LGA) package suitable for automated  
assembly by standard surface mount equipment. The  
LTM8027 is Pb-free and RoHS compliant.  
Surface Mount LGA Package  
APPLICATIONS  
n
12V and 42V Automotive and Heavy Equipment  
n
48V Telecom Power Supplies  
L, LT, LTC, LTM, μModule, Linear Technology and the Linear logo 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
12V  
4A  
100  
OUT  
V
IN  
24V  
IN  
V
V
OUT  
IN  
16V TO 60V  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
4.7μF  
s2  
1M  
LTM8027  
RUN  
SS  
BIAS1  
BIAS2  
AUX  
22μF  
s4  
SYNC  
RT  
ADJ  
GND  
48.7k  
56.2k  
3845 TA01a  
0
1
2
3
4
LOAD (A)  
8027 TA01b  
8027f  
1
LTM8027  
ABSOLUTE MAXIMUM RATINGS  
PIN CONFIGURATION  
(Note 1)  
TOP VIEW  
V Voltage................................................................65V  
IN  
BIAS1, BIAS2 ............................................................15V  
11  
10  
9
V
OUT  
SYNC, ADJ, R , RUN, SS Voltages..............................5V  
BANK 1  
T
Current Into RUN Pin (Note 2) .................................1mA  
8
V
, AUX.................................................................25V  
AUX  
7
GND  
BANK 2  
OUT  
BIAS1  
SS  
RUN  
BIAS2  
ADJ  
6
5
4
3
2
1
Current Out of AUX ............................................. 200mA  
Internal Operating Temperature  
(Note 3).................................................. –40°C to 125°C  
Maximum Soldering Temperature......................... 245°C  
Storage Temperature Range .................. –55°C to 125°C  
V
IN  
BANK 3  
A
B
C
D
E
F G H J K L  
RT  
SYNC  
LGA PACKAGE  
113-LEAD (15mm s 15mm s 4.32mm)  
= 125°C, θ = 12.2°C/W, θ = 9.3°C/W,  
T
JMAX  
θ
JA  
JC(TOP)  
= 7.54°C/W  
= 3.6°C/W, θ  
JC(BOTTOM)  
JBOARD  
θ VALUES DETERMINED PER JESD 51-9  
WEIGHT = 2.6 GRAMS  
ORDER INFORMATION  
LEAD FREE FINISH  
LTM8027EV#PBF  
LTM8027IV#PBF  
LTM8027MPV#PBF  
TRAY  
PART MARKING  
PACKAGE DESCRIPTION  
INTERNAL TEMPERATURE RANGE  
–40°C to 125°C  
LTM8027EV#PBF  
LTM8027IV#PBF  
LTM8027MPV#PBF  
LTM8027V  
113-Lead (15mm × 15mm × 4.32mm) LGA  
113-Lead (15mm × 15mm × 4.32mm) LGA  
113-Lead (15mm × 15mm × 4.32mm) LGA  
LTM8027V  
–40°C to 125°C  
LTM8027V  
–55°C to 125°C  
Consult LTC Marketing for parts specified with wider operating temperature ranges.  
Consult LTC Marketing for information on non-standard lead based finish parts.  
For more information on lead free part marking, go to: http://www.linear.com/leadfree/  
This product is only offered in trays. For more information go to: http://linear.com/packaging/  
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full 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  
0 < I  
≤ 4A, V = 48V  
24  
OUT  
OUT  
OUT  
IN  
I
V
IN  
≤ 60V, V  
= 12V, (Note 4)  
OUT  
0
4
A
V
7.5  
V
IN(START)  
V
V
= 12V, 15V< V < 60V, I  
= 4A  
≤ 4A  
0.2  
0.2  
4.6  
%
%
V
ΔV /ΔV  
OUT  
IN  
LOAD  
OUT  
IN  
Load Regulation  
= 12V, V = 24V, 0A < I  
ΔV /ΔI  
OUT  
IN  
LOAD  
OUT LOAD  
UVLO(RISING)  
V
V
Input Undervoltage Lockout Threshold  
(Rising)  
(Note 5)  
Input Undervoltage Lockout Threshold  
(Falling)  
(Note 5)  
3.7  
V
UVLO(FALLING)  
8027f  
2
LTM8027  
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full 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  
V
ADJ  
ADJ Voltage  
1.224  
1.215  
1.238  
1.245  
V
V
l
IQ  
Quiescent Current into IN  
V
V
= V , V = 12VDC, No Load  
AUX OUT  
39  
9
mA  
μA  
VIN  
BIAS1  
BIAS1  
BIAS  
RUN  
= 0V  
V
BIAS1 Undervoltage Lockout (Rising)  
BIAS1 Undervoltage Lockout (Falling)  
6.5  
6
V
V
I
Current into BIAS1  
No Load  
RUN = 0V  
25  
25  
mA  
μA  
V
Minimum BIAS2 Voltage  
Current Into BIAS2  
6
1
V
μA  
V
BIAS2  
I
BIAS2  
V
Minimum Voltage to Overdrive INTV  
Regulator  
8.5  
BIAS(MINOV)  
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
SW  
R = 187kΩ  
T
100  
500  
kHz  
kHz  
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 the V is externally driven above 6.5V.  
CC  
8027f  
3
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  
IN  
IN  
IN  
IN  
IN  
12V  
24V  
36V  
48V  
60V  
IN  
IN  
IN  
IN  
IN  
5V  
24V  
36V  
48V  
60V  
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  
IN  
IN  
IN  
IN  
IN  
24V  
24V  
24V  
36V  
48V  
60V  
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
3000  
2500  
2000  
1500  
1000  
500  
24V  
IN  
IN  
IN  
IN  
36V  
48V  
60V  
36V  
48V  
60V  
IN  
IN  
IN  
0
0
1
2
3
4
0
1
2
3
4
0
20  
30  
(V)  
40  
50  
60  
10  
LOAD (A)  
LOAD (A)  
V
IN  
8027 G07  
8027 G08  
8027 G09  
8027f  
4
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  
3500  
3000  
2500  
2000  
1800  
1600  
1400  
1200  
1000  
800  
3000  
2500  
5V  
IN  
12V  
5V  
IN  
IN  
12V  
IN  
24V  
36V  
48V  
60V  
12V  
IN  
IN  
IN  
IN  
IN  
24V  
IN  
24V  
IN  
36V  
IN  
36V  
IN  
48V  
60V  
IN  
IN  
2000  
1500  
2000  
1500  
1000  
500  
0
1000  
500  
0
600  
400  
200  
0
1
2
4
0
3
3
3
0
1
2
3
3
3
4
0
1
2
3
4
LOAD (A)  
LOAD (A)  
LOAD (A)  
8027 G10  
8027 G11  
8027 G43  
Input Current vs Load,  
VOUT = 8V  
Input Current vs Load,  
VOUT = 12V  
Input Current vs Load,  
VOUT = 15V  
3500  
3000  
2500  
2500  
2000  
1500  
1000  
500  
3000  
2500  
24V  
IN  
12V  
IN  
24V  
IN  
36V  
IN  
24V  
IN  
36V  
IN  
48V  
IN  
60V  
IN  
36V  
IN  
48V  
IN  
60V  
IN  
48V  
60V  
IN  
IN  
2000  
1500  
2000  
1500  
1000  
500  
0
1000  
500  
0
0
1
2
4
1
2
0
3
0
4
0
1
2
4
LOAD (A)  
LOAD (A)  
LOAD (A)  
8027 G12  
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
3
4
0
1
2
4
2
0
1
4
LOAD (A)  
LOAD (A)  
LOAD (A)  
8027 G15  
8027 G16  
8027 G17  
8027f  
5
LTM8027  
TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C unless otherwise noted)  
Bias Current vs Load,  
Bias Current vs Load,  
VOUT = 5V  
Bias Current vs Load,  
VOUT = 8V  
V
OUT = 3.3V  
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  
2
4
1
2
3
0
0
1
3
3
3
4
2
0
1
3
3
3
4
LOAD (A)  
LOAD (A)  
LOAD (A)  
8027 G20  
8027 G18  
8027 G19  
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  
38  
37  
36  
35  
34  
33  
32  
31  
30  
29.5  
29.0  
28.5  
28.0  
27.5  
27.0  
26.5  
26.0  
25.5  
25.0  
48V  
36V  
24V  
IN  
IN  
IN  
48V  
36V  
24V  
IN  
IN  
IN  
48V  
36V  
IN  
IN  
0
1
2
2
4
2
4
0
1
4
0
1
3
LOAD (A)  
LOAD (A)  
LOAD (A)  
8027 G22  
8027 G21  
8027 G23  
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  
36V  
IN  
IN  
0
1
2
4
0
1
2
3
4
2
0
1
4
LOAD (A)  
LOAD (A)  
LOAD (A)  
8027 G25  
8027 G26  
8027 G44  
8027f  
6
LTM8027  
TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C unless otherwise noted)  
Minimum VIN vs Load,  
Minimum VIN vs Load,  
Minimum VIN vs Load,  
V
OUT = 12V  
V
OUT = 15V  
V
OUT = 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
2
0
1
2
3
4
0
1
3
3
3
4
0
1
3
4
LOAD (A)  
LOAD (A)  
LOAD (A)  
8027 G29  
8027 G27  
8027 G28  
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
5
10  
15  
(V)  
25  
0
20  
1
2
4
0
2
0
1
3
4
V
LOAD (A)  
LOAD (A)  
OUT  
8027 G31  
8027 G30  
8027 G45  
Minimum VIN vs Load,  
VOUT = –5V  
Minimum VIN vs Load,  
VOUT = –8V  
Minimum VIN vs Load,  
VOUT = –12V  
50  
45  
40  
35  
30  
25  
20  
15  
10  
5
12  
10  
30  
25  
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 G32  
8027 G33  
8027 G34  
8027f  
7
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
45  
40  
35  
30  
25  
20  
15  
10  
5
42  
37  
32  
27  
22  
17  
12  
7
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
0
2
2
0
1
3
4
2
4
2
0
1
3
0
1
3
4
LOAD (A)  
LOAD (A)  
LOAD (A)  
8027 G36  
8027 G37  
8027 G35  
Temperature Rise vs Load,  
VOUT = 8V  
Temperature Rise vs Load,  
VOUT = 12V  
Temperature Rise vs Load,  
VOUT = 15V  
70  
60  
50  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
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
0
1
3
4
2
0
1
3
4
LOAD (A)  
LOAD (A)  
LOAD (A)  
8027 G38  
8027 G40  
8027 G39  
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  
26V  
36V  
IN  
IN  
IN  
0
1
2
3
4
0
1
2
3
4
LOAD (A)  
LOAD (A)  
8027 G41  
8027 G42  
8027f  
8
LTM8027  
PIN FUNCTIONS  
V (Bank3):TheV pinsuppliescurrenttotheLTM8027’s  
GND (Bank 2): Tie these GND pins to a local ground plane  
IN  
IN  
internal regulator and to the internal power switch. This  
pin must be locally bypassed with an external, low ESR  
capacitor (see Table 2).  
below the LTM8027 and the circuit components.  
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
(Bank 1): Power Output Pins. Apply the output filter  
OUT  
capacitor and the output load between these and the GND  
pins.  
AUX (Pin A7): Low Current Voltage Source for BIAS1and  
BIAS2.Inmanydesigns,theBIASpinsaresimplyconnected  
SYNC (Pin C1): The SYNC pin provides an external clock  
to V . The AUX pin is internally connected to V  
and  
input for synchronization of the internal oscillator. The  
OUT  
OUT  
is placed near the BIAS pins to ease printed circuit board  
R resistor should be set such that the internal oscilla-  
T
routing. Although this pin is internally connected to V  
,
tor frequency is 10% to 25% below the external clock  
frequency. If unused, the SYNC pin is connected to GND.  
FormoreinformationseeOscillatorSyncintheApplication  
Information section of this data sheet.  
OUT  
do NOT connect this pin to the load. If this pin is not tied  
to BIAS1 and BIAS2, leave it floating.  
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. For proper operation, connect this  
pin to the same power source as BIAS2.  
ADJ (Pin A2): The LTM8027 regulates its ADJ pin to 1.23V.  
Connect the adjust resistor from this pin to ground. The  
value of R  
is given by the equation:  
ADJ  
R
= 613.77/(V  
– 1.23)  
OUT  
ADJ  
where R  
is in kΩ.  
ADJ  
BIAS2 (Pin A3): Internal Biasing Power. This pin must be  
connected to the same power source as BIAS1 for proper  
operation. Always connect this pin to a voltage source  
above 8.5V. Do not leave BIAS2 floating.  
SS (Pin A5): The soft-start pin is used to program the  
supply soft-start function. Use the following formula to  
calculate C for a given output voltage slew rate:  
SS  
C
= 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 cur-  
rent in to the RUN pin to less than 1mA. If the shutdown  
SS  
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.  
8027f  
9
LTM8027  
BLOCK DIAGRAM  
V
IN  
V
OUT  
6.8μH  
4.7pF  
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  
switching DC/DC power supply with an input voltage  
range of 4.5V to 60V that can deliver up to 4A of output  
current.Thismoduleprovidesapreciselyregulatedoutput  
voltage 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. The  
CC  
bias regulator normally draws power from the V pin, but  
IN  
if the BIAS1and BIAS2 pins are connected to an external  
voltage higher than 8.5V, bias power will be drawn from  
theexternalsource(typicallytheregulatedoutputvoltage).  
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 10μA.  
8027f  
10  
LTM8027  
APPLICATIONS INFORMATION  
For most applications, the design process is straight  
forward, summarized as follows:  
inductance forms a high Q (under damped) tank circuit.  
If the LTM8027 circuit is plugged into a live supply, the  
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.  
2. Apply the recommended C , C , R and R values.  
IN OUT ADJ  
T
Input Power Requirements  
3. Connect the BIAS pins as indicated.  
The LTM8027 is biased using an internal linear regula-  
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.  
tor to generate operational voltages from the V pin.  
IN  
Virtually all of the circuitry in the LTM8027 is biased via  
this internal linear regulator output (INTV ). This pin is  
CC  
internally decoupled with a low ESR capacitor to GND.  
The V regulator generates an 8V output provided there  
CC  
Capacitor Selection Considerations  
is ample voltage on the V pin. The V regulator has  
IN  
CC  
The C and C  
capacitor values in Table 2 are the  
IN  
OUT  
approximately 1V of dropout, and will follow the V pin  
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.  
with voltages below the dropout threshold.  
The LTM8027 has a typical start-up requirement of V >  
IN  
7.5V. This assures that the onboard regulator has ample  
headroom to bring INTV above its UVLO threshold.  
CC  
The INTV regulator can only source current, so forcing  
CC  
the BIAS pin above 8.5V allows use of externally derived  
power for the IC. This effectively shuts down the internal  
linear regulator and reduces power dissipation within the  
LTM8027. Using the onboard regulator for start-up, then  
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.  
deriving power for V from the converter output maxi-  
CC  
mizes conversion efficiencies and is common practice. If  
V
ismaintainedabove6.5Vusinganexternalsource,the  
CC  
LTM8027 can continue to operate with V as low as 4V.  
IN  
BIAS Power  
The internal circuitry of the LTM8027 is powered by the  
INTV bus, which is derived either from the afore men-  
CC  
Ceramic capacitors are also piezoelectric. The LTM8027’s  
switching frequency depends on the load current, and  
at light loads it can excite a ceramic capacitor at audio  
frequencies, generating audible noise.  
tioned internal linear regulator or the BIAS1 and BIAS2  
pins, if it is greater than 8.5V. Since the internal linear  
regulator is by nature dissipative, deriving INTV from  
CC  
an external source through the BIAS pins reduces the  
power lost within the LTM8027 and can increase overall  
system efficiency.  
A final precaution regarding ceramic capacitors concerns  
the maximum input voltage rating of the LTM8027. A  
ceramic input capacitor combined with trace or cable  
8027f  
11  
LTM8027  
APPLICATIONS INFORMATION  
For example, suppose the LTM8027 needs to provide 5V  
Operating Frequency Tradeoffs  
from an input voltage source that is nominally 12V. From  
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.  
Table 2, the recommended R value is 162k, which cor-  
T
responds to an operating frequency of 210kHz. From the  
graphs in the Typical Performance Characteristics, the  
typical INTV current at 12V and 210kHz is 15mA. The  
CC  
IN  
power dissipated by the internal linear regulator at 12V  
IN  
The value of R for a given operating frequency can be  
T
is given by the equation:  
chosen from Figure 1 or Table 1.  
P
= (V – 8.5) • I  
IN INTVCC  
INTVCC  
600  
500  
400  
300  
200  
100  
0
or only 54mW. This has a small but probably acceptable  
effect on the operating temperature of the LTM8027.  
If the input rises to 60V, however, the power dissipation is  
a lot higher, over 750mW. This can cause unnecessarily  
high junction temperatures if the INTV regulator must  
CC  
dissipate this amount of power for very long.  
Soft-Start  
The soft-start function controls the slew rate of the power  
supply output voltage during start-up. A controlled output  
voltagerampminimizesoutputvoltageovershoot,reduces  
0
50  
100  
(kΩ)  
150  
200  
R
T
8027 F01  
inrush current from the V supply, and facilitates supply  
Figure 1. Timing Resistor (RT) Value  
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.  
Table 1 lists typical resistor values for common operating  
frequencies.  
Table 1. RT Resistor Values vs Frequency  
R (kΩ)  
T
f
(kHz)  
SW  
187  
118  
100  
150  
200  
250  
300  
350  
400  
450  
500  
During a V UVLO, INTV undervoltage or RUN event,  
IN  
CC  
82.5  
the SS pin voltage is discharged with a 50μA. 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 removed  
63.4k  
48.7k  
40.2k  
31.6k  
27.4k  
23.7k  
the V pin voltage starts to recover. The soft-start circuit  
ADJ  
takes control of the output voltage slew rate once the  
V
pin voltage has exceeded the slowly ramping SS pin  
ADJ  
voltage, reducing the output voltage overshoot during a  
short-circuit recovery.  
8027f  
12  
LTM8027  
APPLICATIONS INFORMATION  
It is recommended that the user apply the R value given  
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  
T
in Table 2 for the input and output operating condition.  
System level or other considerations, however, may ne-  
cessitateanotheroperatingfrequency.WhiletheLTM8027  
is flexible enough to accommodate a wide range of oper-  
ating 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 frequency that is too low can result in a final design  
that has 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.  
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  
Input UVLO and RUN  
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.  
Output Voltage Programming  
tripping UVLO. Resistors are chosen by first selecting R  
(refer to Figure 2). Then:  
B
The LTM8027 regulates its ADJ pin to 1.23V. Connect the  
adjust resistor from this pin to ground. The value of R  
ADJ  
– 1.23),  
is given by the equation R  
= 613.77/(V  
V
⎛
⎜
⎞
ADJ  
OUT  
IN(ON)  
RA =RB •  
–1  
where R  
is in kΩ.  
⎟
ADJ  
1.4V  
⎝
⎠
RUN Control  
whereV  
istheinputvoltageatwhichtheundervoltage  
IN(ON)  
The LTM8027 RUN pin uses a reference threshold of  
1.4V. This precision threshold allows use of the RUN pin  
for both logic-level controlled applications and analog  
monitoringapplicationssuchaspowersupplysequencing.  
The LTM8027 operational status is primarily controlled  
by a UVLO circuit on internal power source. When the  
lockout is disabled and the supply turns on.  
V
SUPPLY  
R
R
A
B
RUN PIN  
LTM8027 is enabled via the RUN pin, only the V regula-  
CC  
tor is enabled. Switching remains disabled until the UVLO  
8027 F02  
threshold is achieved at the V pin, when the remainder  
CC  
of the LTM8027 is enabled and switching commences.  
Figure 2. Undervoltage Lockout Resistive Divider  
8027f  
13  
LTM8027  
APPLICATIONS INFORMATION  
Example: Select R = 49.9k, V  
= 14.5V (based upon  
Hot-Plugging Safely  
B
IN(ON)  
a 15V minimum input voltage)  
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 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-  
14.5V  
1.4V  
⎛
⎞
⎠
R = 49.9k •  
–1 = 464k  
⎜
⎝
⎟
A
The V turn off voltage is 15% below turn on. In the ex-  
IN  
ample the V  
would be 12.3V. The shutdown function  
IN(OFF)  
can be disabled by connecting the RUN pin to the V pin  
IN  
through a large value pull-up resistor. This pin contains  
age at the V pin of the LTM8027 can ring to twice the  
a low impedance clamp at 6V, so the RUN pin will sink  
IN  
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 adding  
an inexpensive electrolytic bulk capacitor across the input  
terminals of the LTM8027. The criteria for selecting this  
capacitoristhattheESRishighenoughtodamptheringing,  
and the capacitance value is several times larger than the  
LTM8027ceramicinputcapacitor. Thebulkcapacitordoes  
not need to be located physically close to the LTM8027;  
it should be located close to the application board’s input  
connector, instead.  
current from the pull-up resistor (R ):  
PU  
V – 6V  
IN  
IRUN  
=
RPU  
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.  
Soft-Start  
The desired soft-start time (t ) is programmed via the  
SS  
Synchronization  
C
capacitor as follows:  
SS  
The oscillator can be synchronized to an external clock.  
2µA • tSS  
1.231V  
CSS  
=
Choose the R resistor such that the resultant frequency is  
T
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.  
The amount of time in which the power supply must be  
under a V , V or V UVLO fault condition (t )  
IN CC  
SHDN  
FAULT  
before the SS pin voltage enters its active region is ap-  
proximated by the following formula:  
CSS • 0.65V  
tFAULT  
=
50µA  
8027f  
14  
LTM8027  
APPLICATIONS INFORMATION  
PCB Layout  
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  
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.  
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.  
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.  
Thermal Considerations  
2. Place the C capacitor as close as possible to the V  
IN  
IN  
The LTM8027 output current may need to be derated if it is  
requiredtooperateinahighambienttemperatureordeliver  
alargeamountofcontinuouspower.Theamountofcurrent  
deratingisdependentupontheinputvoltage,outputpower  
and ambient temperature. The temperature rise curves  
given in the Typical Performance Characteristics section  
can be used as a guide. These curves were generated by a  
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  
4. Place the C and C  
capacitors such that their  
IN  
OUT  
ground current flow directly adjacent to or underneath  
the LTM8027.  
2
LTM8027 mounted to a 58cm 4-layer FR4 printed circuit  
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.  
board. Boards of other sizes and layer count can exhibit  
differentthermalbehavior,soitisincumbentupontheuser  
to verify proper operation over the intended system’s line,  
load and environmental operating conditions.  
V
OUT  
C
OUT  
C
OUT  
GND  
AUX  
BIAS1  
SS  
RUN  
C
IN  
V
IN  
BIAS2  
R
ADJ  
R
T
GND  
8027 F03  
SYNC  
Figure 3. Suggested Layout  
8027f  
15  
LTM8027  
APPLICATIONS INFORMATION  
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.  
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, result-  
ing in impaired performance or reliability. Please refer to  
the PCB Layout section for printed circuit board design  
suggestions.  
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/BIAS2  
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  
8027f  
16  
LTM8027  
TYPICAL APPLICATIONS  
5V VOUT Step-Down Converter  
3.3V VOUT Step-Down Converter  
V
3.3V  
4A  
V
5V  
4A  
OUT  
OUT  
V
*
V
IN  
7.5V TO 60V  
IN  
V
IN  
V
V
V
OUT  
OUT  
IN  
4.5V TO 40V  
10μF  
s2  
4.7μF  
s2  
1M  
1M  
LTM8027  
LTM8027  
9V  
9V  
RUN  
SS  
BIAS1  
BIAS2  
AUX  
RUN  
SS  
BIAS1  
BIAS2  
AUX  
100μF  
s4  
100μF  
s4  
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  
15V VOUT Step-Down Converter  
V
V
OUT  
OUT  
V
V
15V  
18V  
IN  
IN  
V
IN  
V
V
V
OUT  
OUT  
IN  
20.5V TO 60V  
26V TO 60V  
3.5A  
4A SURGE  
3A  
4A SURGE  
4.7μF  
s2  
4.7μF  
s2  
1M  
1M  
LTM8027  
LTM8027  
9V  
RUN  
SS  
BIAS1  
BIAS2  
AUX  
RUN  
SS  
BIAS1  
BIAS2  
AUX  
22μF  
s4  
10μF  
s4  
SYNC  
RT  
SYNC  
RT  
ADJ  
ADJ  
GND  
GND  
40.2k  
44.2k  
31.6k  
36.5k  
3845 TA04  
3845 TA05  
–12V VOUT Postitive-to-Negative Converter  
V
IN  
V
V
OUT  
IN  
20V TO 48V  
4.7μF  
s2  
1M  
LTM8027  
RUN  
SS  
BIAS1  
BIAS2  
AUX  
22μF  
s4  
SYNC  
RT  
ADJ  
GND  
56.2k  
48.7k  
V
–12V  
3A  
OUT  
3845 TA07  
8027f  
17  
LTM8027  
PACKAGE DESCRIPTION  
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  
8027f  
18  
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  
8027f  
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.  
19  
LTM8027  
PACKAGE PHOTOGRAPH  
RELATED PARTS  
PART NUMBER  
DESCRIPTION  
COMMENTS  
LTM4600  
10A DC/DC μModule Regulator  
Basic 10A DC/DC μModule, 15mm × 15mm × 2.8mm LGA  
–55°C to 125°C Operation, 15mm × 15mm × 2.8mm LGA  
LTM4600HVMPV Military Plastic 10A DC/DC μModule Regulator  
LTM4601/  
LTM4601A  
12A DC/DC μModule with PLL, Output Tracking/  
Margining and Remote Sensing  
Synchronizable, PolyPhase Operation, LTM4601-1 Version has no Remote  
Sensing  
LTM4602  
LTM4603  
6A DC/DC μModule Regulator  
Pin Compatible with the LTM4600  
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  
LTM4604  
LTM4608  
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  
OUT  
8A Low V DC/DC μModule Regulator  
2.375V ≤ V ≤ 5V, 0.8V ≤ V  
≤ 5V, 9mm × 15mm × 2.8mm LGA  
≤ 5V, 6.25mm × 6.25mm × 2.32mm LGA  
IN  
IN  
200mA, 36V DC/DC μModule Regulator  
1A, 36V DC/DC μModule Regulator  
Fixed 450kHz Frequency, 1.25V ≤ V  
OUT  
Adjustable Frequency, 0.8V ≤ V  
Pin Compatible to the LTM8023  
≤ 5V, 11.25mm × 9mm × 2.82mm LGA,  
OUT  
LTM8023  
LTM8025  
2A, 36V DC/DC μModule Regulator  
3A, 36V DC/DC μModule Regulator  
Adjustable Frequency, 0.8V ≤ V  
≤ 5V, 11.25mm × 9mm × 2.82mm LGA,  
OUT  
Pin Compatible to the LTM8022  
0.8V ≤ V ≤ 24V, 9mm × 15mm × 4.32mm LGA  
OUT  
8027f  
LT 1009 • PRINTED IN USA  
LinearTechnology Corporation  
1630 McCarthy Blvd., Milpitas, CA 95035-7417  
20  
●
●
© LINEAR TECHNOLOGY CORPORATION 2009  
(408) 432-1900 FAX: (408) 434-0507 www.linear.com  

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