Linear Technology DC2169A Quick setup guide

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dc2169af
DEMO MANUAL DC2169A
Description
LT8616
Dual 42V Synchronous Monolithic Step-Down
Regulator with 6.5µA Quiescent Current
Demonstrationcircuit2169Ais adualmonolithicstep-down
DC/DC switching regulator featuring the LT
®
8616. The
LT8616 is a high efficiency, high speed, dual synchronous
monolithic step-down switching regulator that consumes
only6.5μAofquiescentcurrent with both channelsenabled.
The demo circuit is designed for 5V, 1.5A and 3.3V, 2.5A
outputs. Both channels contain all switches and neces-
sary circuitry to minimize the external components and
solution size. Fast minimum ON time of 35ns enables high
VIN to low VOUT conversion at high switching frequency.
Independent input voltage, feedback, soft-start and power
good pins for each channel simplify complex power supply
tracking/sequencing requirements.
The inputs of the two channels are connected on the demo
board by default. They can also be separated by removing
the 0Ω resistor (R13) from the board. Each output can
be independently disabled using its own EN/UV pin, while
VIN1 must be connected to 3.4V or above even if only
channel 2 is in use. The demo board has an EMI filter
installed between VIN2 and VEMI. To use the EMI filter, the
inputs should be tied to VEMI.
The switching frequency of both channels can be pro-
grammed either via an oscillator resistor or a common
external clock up to 3MHz.The SYNC pin on the demo
board is grounded by default for Burst Mode
®
operation.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
performance summary
To synchronize to an external clock, move JP1 to SYNC/
MODE and apply the external clock to the SYNC/MODE
turret. The RTresistor (R5) should be chosen to set the
LT8616 internal switching frequency at least 20% below
the lowest synchronization input.
Low ripple Burst Mode operation increases the efficiency
at the light load while keeping the output ripple low.
Figure 1 and Figure 2 show the demo board efficiency for
each channel at 12V input voltage in Burst Mode opera-
tion. Figure 3 shows the temperature rising on DC2169A
demo board with different input voltages under full load
conditions on both channels.
The LT8616 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 for
DC2169A. The LT8616 is assembled in a 28-lead plastic
TSSOP package. Proper board layout is essential for both
low EMI operation and maximum thermal performance.
See the data sheet sections for details.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2169A
Specifications are at TA= 25°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN1 Channel 1 Input Supply Range 5.8 42 V
VIN2 Channel 2 Input Supply Range 4.1 42 V
VOUT1 Channel 1 Output Voltage 4.88 5.02 5.15 V
VOUT2 Channel 2 Output Voltage 3.21 3.29 3.37 V
fSW Switching Frequency RT= 14.7kΩ 1.85 2.05 2.25 MHz
IOUT1 Channel 1 Max Output Current 1.5 A
IOUT2 Channel 2 Max Output Current 2.5 A
EFE Efficiency at DC VIN1 = VIN2 = 12V, IOUT1 = 1.5A, IOUT2 = 2.5A 85.1 %

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DEMO MANUAL DC2169A
performance summary
Figure 1. LT8616 Channel 1 Efficiency vs Load Current
LOAD CURRENT (A)
50
EFFICIENCY (%)
70
100
60
80
90
0.6
DC2169A F01
1.50.30 0.9 1.2
fSW = 2MHz
VIN1 = 12V
VOUT1 = 5V
LOAD CURRENT (A)
50
EFFICIENCY (%)
70
100
60
80
90
1
DC2169A F02
2.50.50 1.5 2
fSW = 2MHz
VIN2 = 12V
VOUT2 = 3.3V
INPUT VOLTAGE (V)
20
TEMPERATURE RISING (°C)
60
100
40
80
24
DC2169A F03
40168 32
fSW = 2.05MHz
VOUT1 = 5V, IOUT1 = 1.5A
Figure 2. LT8616 Channel 2 Efficiency vs Load Current
Figure 3. LT8616 Temperature Rising vs Input Voltage

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DEMO MANUAL DC2169A
DC2169A is easy to set up to evaluate the performance
of the LT8616. Refer to Figure 4 for proper measurement
equipment setup and follow the procedure below:
NOTE: When measuring the input or output voltage ripple,
care must be taken to avoid a long ground lead on the
oscilloscope probe. Measure the input or output voltage
ripple by touching the probe tip directly across the VIN
or VOUT and GND terminals. See Figure 5 for the proper
scope technique.
1. Place JP1 on the Burst Mode position.
2. With power off, connect the input power supply to VEMI
and GND. Make sure that the input voltage does not
exceed 42V.
3. With power off, connect loads from VOUT1 to GND, and
VOUT2 to GND.
4. Turn on the power at the input.
5. Check for the proper output voltages (5V and 3.3V).
NOTE: If there is no output, temporarily disconnect the
load to make sure that the load is not set too high or
is shorted.
6. Once the proper output voltages are established, adjust
the load within the operating ranges and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
7. An external clock can be added to the SYNC terminal
when SYNC function is used (JP1 on the SYNC/MODE
position). Please make sure that the SYNC frequency is
at least 20% higher than the set switching frequency.
See the data sheet section Synchronization.
Quick start proceDure
V
OUT
GND
Figure 4. Proper Measurement Equipment Setup
Figure 5. Measuring Input or Output Ripple

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dc2169af
DEMO MANUAL DC2169A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 2 C2, C3 CAP., X7R, 0.1µF, 10V, 10% 0402 SAMSUNG, CL05B104KP5NNNC
2 1 C4 CAP., X7R, 22µF, 10V, 10% 1210 MURATA, GRM32ER71A226KE20L
3 1 C5 CAP., X7R, 47µF, 10V, 10% 1210 MURATA, GRM32ER71A476KE15L
4 2 C6, C7 CAP., X7R, 0.01µF, 10V, 10% 0603 AVX, 0603ZC103KAT2A
5 2 C8, C9 CAP., C0G, 4.7pF, 50V, ±0.25pF 0603 AVX, 06035A4R7CAT2A
6 2 C10, C11 CAP., X7R, 2.2µF, 50V, 10% 1206 MURATA, GRM31CR71H225KA88L
7 5 C12, C17, C19, C27, C28 CAP., X7R, 1µF, 10V, 10% 0603 AVX, 0603ZC105KAT2A
8 4 C13, C14, C15, C16 CAP., X7R, 0.1µF, 50V, 10% 0402 TDK, C1005X7R1H104K050BB
9 1 L1 IND., 3.3µH, XAL4030 COILCRAFT, XAL4030-332ME
10 1 L2 IND., 2.2µH, XFL4020 COILCRAFT, XFL4020-222ME
11 6 R1, R3, R6, R8, R10, R11 RES., CHIP, 1M, 0.1W, 1%, 0603 VISHAY, CRCW06031M00FKEA
12 1 R2 RES., CHIP, 187k, 0.1W, 1%, 0603 VISHAY, CRCW0603187KFKEA
13 1 R4 RES., CHIP, 316k, 0.1W, 1%, 0603 VISHAY, CRCW0603316KFKEA
14 1 R5 RES., CHIP, 14.7k, 0.1W, 1%, 0603 VISHAY, CRCW060314K7FKEA
15 2 R7, R13 RES., CHIP, 0Ω, 0.1W, 0603 VISHAY, CRCW06030000Z0EA
16 1 U1 IC., LT8616EFE TSSOP-28/EB LINEAR TECH., LT8616EFE#PBF
Additional Demo Board Circuit Components
1 2 C1, C18 CAP., ALUM., 22µF, 63V, SUN ELECTRONIC INDUSTRIES CORP., 63CE22BS
21 L3 CHIP BEAD, 30Ω, MPZ2012 TDK, MPZ2012S300AT
3 1 L4 IND., 0.22µH, IHLP1212AB VISHAY, IHLP1212ABERR22M11
4 1 C23 CAP., X7R, 4.7µF, 50V, 10% 1206 SAMSUNG, CL31B475KBHNNNE
5 1 C24 CAP., X7R, 10µF, 50V, 10% 1210 MURATA, GRM32ER71H106KA12L
6 2 C25, C26 CAP., X7R, 0.1µF, 50V, 10% 0402 TDK, C1005X7R1H104K050BB
7 0 R9, R12 (OPT) RES., CHIP, 0603
Hardware: For Demo Board Only
1 16 E1-E16 TESTPOINT, TURRET, .094" PBF MILL-MAX, 2501-2-00-80-00-00-07-0
2 1 JP1 4 PIN 0.079 SINGLE ROW HEADER SULLINS, NRPN041PAEN-RC
3 1 XJP1 SHUNT, .079" CENTER SAMTEC, 2SN-BK-G

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DEMO MANUAL DC2169A
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.
schematic Diagram
5
5
4
4
3
3
2
2
1
1
D D C C B B A A
1. ALL RESISTORS ARE IN 0603 ALL CAPACITORS ARE IN 0603 NOTE: UNLESS OTHERWISE SPECIFIED
2MHz
63CE22BS 63CE22BS
VIN1 VIN2
SYNC
VOUT1
VIN2
VOUT2 VOUT1
VOUT2
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
www.linear.com
4
DEMO CIRCUIT 2169A
Monday, January 19, 2015 11
DUAL 42V SYNCHRONOUS MONOLITHIC
N/A
LT8616EFE
STEP-DOWN REGULATOR WITH 6.5µA QUIESCENT CURRENT
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
www.linear.com
4
DEMO CIRCUIT 2169A
Monday, January 19, 2015 11
DUAL 42V SYNCHRONOUS MONOLITHIC
N/A
LT8616EFE
STEP-DOWN REGULATOR WITH 6.5µA QUIESCENT CURRENT
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
www.linear.com
4
DEMO CIRCUIT 2169A
Monday, January 19, 2015 11
DUAL 42V SYNCHRONOUS MONOLITHIC
N/A
LT8616EFE
STEP-DOWN REGULATOR WITH 6.5µA QUIESCENT CURRENT
L2
2.2uH
XFL4020-222ME
C26 0.1uF
0402
50V
E7
SYNC/MODE
C24
10uF
50V
1210
E2
GND
C8
4.7pF
E5
GND
JP1
PULSE SKIPPING
BURST MODE
SYNC/MODE
4 Pins 2mm Ctrs.
1 3 2 4
E6 GND
C23
4.7uF
50V
1206
R2
187k
E10
VIN2
4.1V - 42V
C19
1uF
+
C18
22uF
63V
C11
2.2uF
50V
1206
C4 22uF 10V 1210
C16
0.1uF
50V
0402
E11 GND
C14 0.1uF 50V
0402
C27
1uF
E1
VIN1
5.8V - 42V
PAD150-094
E12 PG2
C2
0.1uF
10V
0402
E4
VOUT2 3.3V / 2.5A
R6 1M
C17
1uF
R10 1M
C6 0.01uF
L3
30 ohm
MPZ2012S300AT
E8
SS2/TR2
U1
LT8616EFE
RT
15
FB2 26
BOOST2 6
PG1 11
FB1
14
SW2 3
PG2 2
VIN1 19
TR/SS1
12
TR/SS2
28
INTVCC
21
SW1
9
GND
29
SYNC/MODE
17
BOOST1
8
VIN2 24
NC
7
EN/UV1
16 ENUV2 1
BIAS 22
NC 18
NC 23
NC 20
NC 25
FB2 27
SW2 4 SW2 5
FB1
13
SW1
10
E3
VOUT1
5V / 1.5A
R9 OPT
C28
1uF
C3 0.1uF
10V0402
C12 1uF
C15
0.1uF
50V
0402
R4 316K
E9
SS1/TR1
R1 1M
L1
3.3uH
XAL4030-332ME
R5
14.7k
C13
0.1uF
50V
0402
L4
0.22uH
IHLP1212ABERR22M11
E15
EN1
R8 1M
+
C1
22uF
63V
E16
VEMI
E14 PG1
C10 2.2uF 50V 1206
C7
0.01uF
C5 47uF 10V 1210
R13 0
R7 0
R11 1M
E13 EN2
R3
1M
C9 4.7pF
R12
OPT
C25 0.1uF
0402
50V

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DEMO MANUAL DC2169A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2015
LT 0515 • 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.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LT C from all claims
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.).
No License is granted under any patent right or other intellectual property whatsoever. LT C assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LT C currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
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.
Mailing Address:
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