Linear Technology DC1738A Quick setup guide

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DEMO MANUAL DC1738A
Description
LTM8028
36VIN, UltraFast, Low Output
Noise, 5A µModule Regulator
Demonstration circuit 1738A features the LT M
®
8028, a
µModule
®
step-down converter that integrates both a high
efficiency switching regulator and a 5A UltraFast™ linear
regulator, resulting in a low noise solution suitable for high
speed data applications. The demo circuit is designed for
an input voltage of 6V to 36V and an operating frequency
of 250kHz. The output voltage is digitally programmable
from 0.8V to 1.8V in 50mV increments by adjusting the
three tri-state inputs VO0, VO1, and VO2.
The user may adjust the output voltage over a continuous
±10% range by applying a voltage to MARGA. A PGOOD
signal indicates that the output is within 10% of the target
L, LT, LTC, LTM, Linear Technology, the Linear logo and µModule are registered trademarks
and UltraFast is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
BoarD photo
voltage. The SENSEP pin creates a Kelvin sense connec-
tion to account for voltage drops due to PCB resistances
between the regulator and the load.
The LTM8028 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this demo manual
prior to working on or modifying DC1738A.
Design files for this circuit board are available at
http://www.linear.com/demo

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DEMO MANUAL DC1738A
performance summary
PARAMETER CONDITIONS MIN TYP MAX UNITS
Input Voltage Range VOUT = 0.8V to 1.8V 6 36 V
Output Voltage* Default Setting 1.773 1.8 1.827 V
Maximum Output Current 5 A
Switching Frequency RT= 165kΩ 250 kHz
*For other output voltage settings, refer to Table 1
Specifications are at TA= 25°C
FREQUENCY (MHz)
0
INTENSITY (dBm)
–60
–40
–20
3.5
–80
–100
1 2
0.5 4.5
1.5 2.5 4 3 5
–120
–140
0
dc1738a F01
VIN = 12V
VOUT = 1.5V
IOUT = 5A
Figure 1. DC1738A Output Noise Spectrum
Table 1: VO2 to VO0 Setting vs Nominal Output Voltage
VO2 VO1 VO0 VOUT(NOM)
Low Low Low 0.80V
Low Low Float 0.85V
Low Low High 0.90V
Low Float Low 0.95V
Low Float Float 1.00V
Low Float High 1.05V
Low High Low 1.10V
Low High Float 1.15V
Low High High 1.20V
Float Low Low 1.25V
Float Low Float 1.30V
Float Low High 1.35V
Float Float Low 1.40V
Float Float Float 1.45V
Float Float High 1.50V
Float High Low 1.55V
Float High Float 1.60V
Float High High 1.65V
High Don't Care Low 1.70V
High Don't Care Float 1.75V
High Don't Care High 1.80V

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DEMO MANUAL DC1738A
Quick start proceDure
Demonstration circuit 1738A is an easy way to evaluate
the performance of the LTM8028. Refer to Figure 2 for
proper measurement equipment setup and follow the
procedure below:
1. Place JP1-JP3 according to Table 1 to program the
desired output voltage.
2. With power off, connect the input power supply, load
and meters, as shown in Figure 2. Preset the VIN supply
between 6V to 36V.
3. Turn on the power at the input.
4. Check for the proper output voltage.
NOTE:Ifthereisnooutput,temporarilydisconnecttheload
to make sure that the load is not set too high or is shorted.
5. Once the proper output voltage is established, adjust
the load within the operating range and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
6. In order to use the Kelvin sense connection to account
for output voltage drops, place JP4 in the SENSEP
position and connect the SENSEP turret at the input
of the load.
7. In order to minimize EMI noise, an input filter can be
utilized by removing R6 on the bottom of the board
and populating the optional circuit components.
Figure 2. Proper Measurement Equipment Setup

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DEMO MANUAL DC1738A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 C1 CAP., X7R, 10µF, 50V, 10%, 1210 MURATA, GRM32ER71H106K
2 1 C2 CAP., X7R, 0.01µF, 16V, 5%, 0603 AVX, 0603YC103JAT2A
3 1 C4 CAP., X5R, 100µF, 6.3V, 20%, 1210 AVX, 12106D107MAT2A
4 1 C8 CAP., POSCAP, 470µF, 4V, D3L SANYO, 4TPF470ML
5 1 C9 CAP., X5R, 10µF, 10V, 20%, 0805 TAIYO YUDEN, LMK212ABJ106MG-T
6 1 C10 CAP., X5R, 4.7µF, 4V, 20%, 0603 AVX, 06034D475MAT2A
7 1 C12 CAP., X5R, 22µF, 10V, 20%, 0805 TAIYO YUDEN, LMK212BBJ226MG-T
8 1 R1 RES., CHIP, 402kΩ, 1/10W, 1%, 0603 VISHAY, CRCW0603402KFKEA
9 1 R3 RES., CHIP, 165kΩ, 1/16W, 1%, 0603 VISHAY, CRCW0603165KFKEA
10 2 R4, R7 RES., CHIP, 100kΩ, 1/16W, 1%, 0603 VISHAY, CRCW0603100KFKEA
11 1 R6 RES., CHIP, 0Ω, 1/4W, 1%, 1206 NIC, NRC12ZOTRF
12 1 R9 RES., CHIP, 49.9Ω, 1/16W, 1%, 0603 VISHAY, CRCW060349R9FKEA
13 1 U1 IC., MODULE REGULATOR, LTM8028EY, BGA-114 LEAD LINEAR TECHNOLOGY CORPORATION, LTM8028EY
Additional Demo Board Circuit Components
1 0 C3, C6 (OPT) CAP., 1210
2 0 C5 (OPT) CAP., 0603
3 0 C7 (OPT) CAP., ALUM
4 1 C11 CAP., ALUM, 22µF, 50V SUN ELECT., 50CE22BS
5 0 R2, R5, R8 (OPT) RES., CHIP, 0603
6 0 FB1 (OPT) FERRITE BEAD, M TYPE TAIYO YUDEN, FBMJ3216HS800T
7 0 L1 (OPT) IND., 10µH VISHAY, IHLP-2525CZ-01
Hardware: For Demo Board Only
1 8 E1-E8 TESTPOINT, TURRET, 0.094" MILL-MAX, 2501-2-00-80-00-00-07-0
23 JP1-JP3 JMP, 0.079", SINGLE ROW HEADER, 4 PIN SAMTEC, TMM-104-02-L-S
3 1 JP4 JMP, 0.079", SINGLE ROW HEADER, 3 PIN SAMTEC, TMM-103-02-L-S
4 4 J1-J4 CONN, BANANA JACK, KEYSTONE-575-4 KEYSTONE, 575-4
5 1 J5 CONN, BNC CONNEX, 112404
6 4 XJP1-XJP4 SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G
7 4 MTGS AT 4 CORNERS STAND-OFF, SNAP-ON, NYLON, 0.50" TALL

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DEMO MANUAL DC1738A
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.
Figure 3. DC1738A Demo Circuit Schematic
schematic Diagram
5 5
4 4
3 3
2 2
1 1
D D C C B B A A
NOTE: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTORS AND CAPACITORS ARE 0603
MARGA
OPTIONAL CIRCUIT
1210 IHLP-2525CZ-01
LOW HIGH
SYNC
1210
2. INSTALL SHUNTS AS SHOWN.
* REFER TO DEMO MANUAL
6.3V 1210 D3L
1210
0805
FLOAT
1206
0V - 1.2V
VO2 *VO1 *VO0 *
LOW HIGH FLOAT
LOW HIGH FLOAT
REMOVE R6 IF OPTIONAL CIRCUIT IS USED.
**
BNC
PGOOD
0805
SENSEP
SENSEP
VOUT
**
**
IN
VIN
INVIN
VOBVOB VOB VOB
VOB
R9
49.9
R9
49.9
JP1JP1
1 3 2 4
FB1 Bead FB1 Bead
R7
100K
R7
100K
E4E4
C5 0.01uF 50V C5 0.01uF 50V
C3 OPT. C3 OPT.
C2 10nF C2 10nF
R5
OPT
R5
OPT
+
C7 22uF 50V
+
C7 22uF 50V
E1E1
J3
VOUT 0.8V - 1.8V / 5A
J3
VOUT 0.8V - 1.8V / 5A
+
C8 470uF 4V
+
C8 470uF 4V
R6
0
R6
0
E6E6
JP4JP4
1 3 2
R4
100K
R4
100K
C9 10uF 10V C9 10uF 10V
C4 100uF C4 100uF
JP2JP2
1 3 2 4
E2E2
E5E5
E8E8
C6 10uF 50V C6 10uF 50V
J1
VIN
6V - 36V
J1
VIN
6V - 36V
C1 10uF 50V C1 10uF 50V
R1
402K
R1
402K C12
22uF 10V C12 22uF 10V
J5J5
J4 GND J4 GND
R2
OPT
R2
OPT
E3E3
+
C11 22uF 50V
+
C11 22uF 50V
U1
LTM8028EY
U1
LTM8028EY
RT
E1
VO1 B6
BKV K11 BKV K10
VIN
H1
BKV K9
VIN
H2
VIN
J1
VOUT A11 VOUT A10
VIN
J2
VIN
K1
VIN
K2
VIN
L1
VIN
L2
RUN
F1
SYNC
E2
VOUT B10 VOUT C10
BKV L9 BKV J9
SS
D2
VOUT B11 VOUT C11 VOUT D10
IMAX
D1
BKV J11 BKV J10
VOUT D11 VOUT E10 VOUT E11
TEST A8
BKV L11 BKV L10
VOUT F10 VOUT F11
SENSEP A9
GND
A1
VO0 A6
VOB B5
VO2 A5
GND
A2
GND
A3
GND
A4
GND
B1
GND
B2
GND
B3
GND
B4
GND
B8
GND
B9
GND
C1
GND
C2
GND
C3
GND
C4
GND
C5
GND
C6
GND
C7
GND
C8
GND
C9
GND
D3
GND
D4
GND
D5
GND
D6
GND
D7
GND
D8
GND
D9
GND
E3
GND
E4
GND
E5
GND
E6
GND
E7
GND
E8
GND
E9
GND
F2
GND
F3
GND
F4
GND
F5
GND
F6
GND
F7
GND
F8
GND
F9
GND
G4
GND
G5
GND
G6
GND
G7
GND
G8
GND
G9
GND
G10
GND
G11
GND
H4
GND
H5
GND
H6
GND
H7
GND
H8
GND
H9
GND
H10
GND
H11
GND
J4
GND
J5
GND
J6
GND
J7
GND
J8
GND K4 GND K5 GND K6 GND K8 GND L4 GND L5 GND L6 GND L8
MARGA A7
GND K7 GND L7
PGOOD
B7
L1
10uH
L1
10uH
E7E7
R8
OPT
R8
OPT
JP3JP3
1 3 2 4
C10 4.7uF 4V 0603 C10 4.7uF 4V 0603
J2
GND J2 GND
R3 165K R3 165K

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DEMO MANUAL DC1738A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2013
LT 0413 • PRINTED IN USA
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LT C ) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LT C for commercial use. As such, the DEMO BOARD herein may not be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
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arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
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customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
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Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LT C applica-
tion engineer.
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