Linear Technology Analog Devices DC2688A Quick setup guide

1
DEMO MANUAL DC2688A
Rev. 0
DESCRIPTION
LT8698S/LT8698S-1
5V 3A, 42V Input USB Charger with Cable Drop
Compensation and Data Line Protection
Demonstration circuit 2688A is a USB charger designed
to power the 5V USB V
BUS
rail with up to 3A from an
input voltage as high as 42V. The DC2688A circuit fea-
tures the LT
®
8698S/LT8698S-1, which is a compact, high
efficiency, high speed synchronous monolithic step-down
switching regulator which features the second-genera-
tion Silent Switcher
®
technology that minimizes EMI and
reduces PCB layout sensitivity. The LT8698S/LT8698S-1
supports a wide variety of portable device charger pro-
files including USB BC 1.2 CDP, DCP, and SDP as well as
common proprietary charger profiles, all of which can
be easily evaluated using the DC2688A demo board. The
LT8698S/LT8698S-1 also features high speed USB 2.0
compliant data line switches, robust data line protection,
and programmable cable drop compensation which main-
tains accurate 5V VBUS regulation even when USB sockets
are separated from the LT8698S/LT8698S-1 by a long
cable. These features make the LT8698S/LT8698S-1 well
suited for automotive USB host applications.
There are two assembly versions. The DC2688A-A fea-
tures the LT8698S, while the DC2688A-B features the
LT8698S-1. The difference is that the LT8698S includes
VIN hot loop capacitors inside the IC package for improved
EMI/EMC performance, while the LT8698S-1 does not
include these capacitors.
DEMO BOARD INFORMATION
The main power stage of the DC2688A demo board oper-
ates at 2MHz switching frequency by default to minimize
solution size. The jumper JP5 on the demo board deter-
mines the configuration of the SYNC pin of the LT8698S/
LT8698S-1. Setting the jumper JP5 to “FCM W/SSM”
location ties SYNC pin to INTV
CC
which enables forced
continuous mode with spread-spectrum modulation for
improved EMI performance. Moving JP5 to “PSK” loca-
tion enables the pulse-skipping mode which improves
light load efficiency by reducing the switching frequency
All registered trademarks and trademarks are the property of their respective owners.
at light load and reducing VIN quiescent current between
pulses. To synchronize to an external clock, move JP5
to “FCM W/O SSM or SYNC”location and apply external
clock on the EXT_SYNC turret.
Figure1 shows a functional Block Diagram of the DC2688A
demo board.
The DC2688A demo board includes a re-timer IC USB2422
whose purpose is to ensure that USB high speed signaling
eye pattern can be measured at test plane2 as defined by
USB 2.0 specifications, and that such signaling through
the LT8698S/LT8698S-1’s USB data line switches con-
forms to template 1 eye pattern requirements. Please note
that a re-timer IC is not necessary in actual applications
as the USB host controller will reside on the same PCB
board as the LT8698S/LT8698S-1.
The DC2688A demo board includes three headers JP2,
JP3, and JP4, which are used for manual control of the
LT8698S/LT8698S-1’s tristate input pins SEL1, SEL2, and
SEL3. Although these select pins are intended to interface
with a USB host microcontroller, majority of the functions
of the LT8698S/LT8698S-1 may be evaluated by simply
using the manual selection of the SEL1, SEL2, and SEL3
headers on the DC2688A board.
The DC2688A demo board is 3.5-inch × 3.5-inch in size
and has four copper layers with 2oz copper on the outer
layers and 1oz copper on the inner layers. The DC2688A
has controlled impedance transmission lines placed for
high speed differential USB data signaling, in between the
USB-B receptacle, the USB2422 re-timer IC, the LT8698S/
LT8698S-1 data line switches, and the USB-A receptacle,
with a differential characteristic impedance of 90Ω.
The default rated maximum load current of the DC2688A
is 2.4A, with a default RSENSE resistor value of 10mΩ.
However, the DC2688A circuit can supply 3A load current
with a RSENSE resistor value of 8mΩ.
Design files for this circuit board are available.

2
DEMO MANUAL DC2688A
Rev. 0
DESCRIPTION
Figure2 shows the efficiency of the DC2688A at 12V and
24V input in pulse-skipping mode of operation (input from
VIN turret pin, and RSENSE resistor is 8mΩ)
The DC2688A has an input EMI filter installed. The EMI
performance of the demo board DC2688A-A (with EMI
filter) is shown in Figure3 and Figure4. The red lines in
Figure3 are CISPR 25 class 5 limits for peak detector. The
EMI performance of DC2688A-B (with EMI filter) is shown
in Figure5 and Figure6. To achieve EMI performance as
shown in Figure3 through Figure6, the input EMI filter
is required, and the input voltage should be applied at
VEMI terminal.
As shown in the dashed box in Figure1 functional block
diagram, the DC2688A demo board may also be optionally
used in conjunction with the Linduino
®
microcontroller
board DC2026Cand a touchscreen display shield. The
DC2688A demo board includes the AD5593R, which is
an 8-channel ADC/GPIO with on-chip reference and I2C
interface. The AD5593R monitors several inputs from the
LT8698S/LT8698S-1, communicates with the Linduino
board through the I2C interface, and controls the SEL1,
SEL2, and SEL3 tristate input pins.
The LT8698S/LT8698S-1 data sheet gives a complete
description of the part, operation and application infor-
mation. The data sheet must be read in conjunction with
this manual forDC2688A.

3
DEMO MANUAL DC2688A
Rev. 0
Figure1. DC2688A Demo Board Functional Block Diagram
DESCRIPTION

4
DEMO MANUAL DC2688A
Rev. 0
Figure2. Efficiency vs Load Current at 2MHz Switching Frequency (Input from VIN Terminal)
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 24V
VIN = 12V
IOUT (A)
0
0.5
1
1.5
2
2.5
3
60
65
70
75
80
85
90
95
EFFICIENCY (%)
DC2688A F02
fSW = 2MHz
PULSE SKIPPING MODE
L = XFL5030-222
RSENSE = 8mΩ
PERFORMANCE SUMMARY
Specifications are at TA= 25°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Input Supply Range 6.0 42 V
VBUS USB 5V Bus Voltage Without Cable Drop Compensation 4.8 5 5.2 V
USB 5V Bus Voltage With Cable Drop Compensation 6.2 V
IBUS Maximum Output Current RSENSE = 10mΩ 2.4 A
Maximum Output Current RSENSE = 8mΩ 3.0 A
fSW Switching Frequency 1.95 2 2.05 MHz
EFE Efficiency at DC VIN = 12V, IBUS1 = 1.5A 92.7 %

5
DEMO MANUAL DC2688A
Rev. 0
Figure3. DC2688A-A Demo Circuit EMI Performance in CISPR 25
Radiated Emissions Test, Peak Detector
Figure4. DC2688A-A Demo Circuit EMI Performance in CISPR 25
Radiated Emissions Test, Average Detector
DC2688A–A DEMO BOARD
(WITH EMI FILTER INSTALLED)
14V INPUT TO 5V
BUS
OUTPUT AT 2.5A, f
SW
= 2MHz
L1 = XFL4020–222ME, C
VIN2
AND C
VIN3
POPULATED
VERTICAL POLARIZATION
PEAK DETECTOR
CLASS 5 PEAK LIMIT
SPREAD SPECTRUM MODE
FIXED FREQUENCY MODE
FREQUENCY (MHz)
0
100
200
300
400
500
600
700
800
900
1000
0
5
10
15
20
25
30
35
40
45
50
AMPLITUDE (dBµV/m)
DC2688A F03
DC2688A–A DEMO BOARD
(WITH EMI FILTER INSTALLED)
14V INPUT TO 5V
BUS
OUTPUT AT 2.5A, f
SW
= 2MHz
L1 = XFL4020–222ME, C
VIN2
AND C
VIN3
POPULATED
VERTICAL POLARIZATION
AVERAGE DETECTOR
CLASS 5 AVERAGE LIMIT
SPREAD SPECTRUM MODE
FIXED FREQUENCY MODE
FREQUENCY (MHz)
0
100
200
300
400
500
600
700
800
900
1000
–10
–5
0
5
10
15
20
25
30
35
40
AMPLITUDE (dBµV/m)
DC2688A F04
TYPICAL PERFORMANCE CHARACTERISTICS
Figure5. DC2688A-B Demo Circuit EMI Performance in CISPR 25
Radiated Emissions Test, Vertical Polarization
Figure6. DC2688A-B Demo Circuit EMI Performance in CISPR 25
Radiated Emissions Test, Horizontal Polarization
CLASS 5 PEAK LIMIT
SPREAD SPECTRUM MODE
FIXED FREQUENCY MODE
VERTICAL POLARIZATION
PEAK DETECTOR
FREQUENCY (MHz)
0
100
200
300
400
500
600
700
800
900
1000
0
5
10
15
20
25
30
35
40
45
50
AMPLITUDE (dBµV/m)
DC2688A F05
DC2688A-B DEMO BOARD (WITH EMI FILTER INSTALLED)
14V INPUT TO 5V VBUS AT 2.5A, fSW = 2MHz, L1 = XFL4020-222ME,
CVIN2 AND CVIN3 POPULATED
CLASS 5 PEAK LIMIT
SPREAD SPECTRUM MODE
FIXED FREQUENCY MODE
HORIZONTAL POLARIZATION
PEAK DETECTOR
FREQUENCY (MHz)
0
100
200
300
400
500
600
700
800
900
1000
0
5
10
15
20
25
30
35
40
45
50
AMPLITUDE (dBµV/m)
DC2688A F06
DC2688A-B DEMO BOARD (WITH EMI FILTER INSTALLED)
14V INPUT TO 5V VBUS AT 2.5A, fSW = 2MHz, L1 = XFL4020-222ME,
CVIN2 AND CVIN3 POPULATED

6
DEMO MANUAL DC2688A
Rev. 0
EVALUATE DC2688A POWER STAGE
Demonstration circuit 2688A is easy to set up to evalu-
ate the performance of the LT8698S/LT8698S-1. Refer to
Figure7 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 long ground lead
on the oscilloscope probe. Measure the output voltage
ripple by touching the probe tip directly across the
VBUS and GND terminals. See Figure7 and Figure8
for proper measurement technique.
1. Check that JP6 and JP7 are placed on the OFF position
to ensure that the on-board LDOs are disabled.
2. Place JP2, JP3, and JP4 all on the “Z” position, which
puts the LT8698S/LT8698S-1 in VBUS only mode of
operation with VBUS in regulation.
3. With power off, connect the input power supply to
VEMI and GND turrets. If the EMI/EMC performance
is not important, connect the input power supply to
VIN and GND turrets.
4. With power off, connect the loads from VBUS to GND.
5. Check that JP1 EN jumper is placed on the ONposition.
6. Turn on the power at the input.
NOTE:Make sure that the input voltage never
exceeds42V.
7. Check for proper output voltages:VBUS voltage should
be between 5V to 6.1V and depends on the cable drop
QUICK START PROCEDURE
compensation settings, and D11 LED indicator lights
up in green. For more information on cable drop
compensation, please refer to LT8698S/LT8698S-1
datasheet.
NOTE: If there is no output, temporarily disconnect
the load to make sure that the load is not set too high.
8. 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.
9. An external clock can be added to the EXT_SYNC ter-
minal when SYNC function is used (JP5 on the FCM
W/O SSM OR SYNC position). Please make sure that
R37 resistor should be chosen to set the LT8698S/
LT8698S-1 switching frequency equal to or below the
lowest synchronization frequency. JP5 can also set
the LT8698S/LT8698S-1 in spread-spectrum mode
(JP5 on the FCM W/SSM position) or pulse skipping
mode (JP5 on the PSK position).
10. Check STATUS pin voltage on the STATUS turret in
relation to the IBUS load current. If IBUS load is lower
than 100mA typically, STATUS pin should be low, and
the STATUS LED lights up in yellow;if IBUS load is
higher than 130mA typically, STATUS pin should be
high, and the STATUS LED does not light up.
11. Check IMON point voltage, in relation to IBUS load cur-
rent. Measure the voltage on the IMON turret:the
IMON voltage should be equal to 0.46V/A in propor-
tion to the IBUS load current.

7
DEMO MANUAL DC2688A
Rev. 0
Figure7. Proper Measurement Equipment Setup for Evaluating the DC2688A-B Power Stage
QUICK START PROCEDURE
Figure8. Measuring Output Ripple
V
A
IBUS
LOAD
+
–
–
+
+
–
V
A
–
–
+
–
+
POWER
SUPPLY
+
VIN
JP2 = Z
JP4 = Z
JP3 = Z
VBUS
IIN
VIN
V
BUS
GND

8
DEMO MANUAL DC2688A
Rev. 0
EVALUATE USB CHARGER PROFILES
The LT8698S/LT8698S-1 supports several common USB
charger profiles, and the DC2688A demo board is easy to
set up to evaluate these common charger profiles.
Refer to Figure9 for proper measurement equipment
setup and follow the procedure below.
1. Check that JP6 and JP7 are placed on the OFF posi-
tion, to ensure that the on-board LDOs are disabled.
2. Select JP2, JP3, and JP4 jumpers at appropriate
locations based on the desired charger profile and
SEL pin lookup table in the LT8698S/LT8698S-1 data
sheet. Table1 shows several popular USB charger
profiles available in the LT8698S/LT8698S-1. Refer
to LT8698S/LT8698S-1 data sheet for further infor-
mation about USB charger profiles.
3. With power off, connect the input power supply to
VEMI and GND turrets. If the EMI/EMC performance
is not important, connect the input power supply to
VIN and GND turrets.
4. Check that JP1 EN jumper is placed on the ONposition.
QUICK START PROCEDURE
5. Turn on the power at the input.
NOTE:Make sure that the input voltage never
exceeds42V.
6. Check for proper output voltages:V
BUS
= 5V, and D11
LED indicator lights up in green.
7. Attach a portable device to the type A socket of the
DC2688A demo board.
8. Observe the battery charging activity on the
portabledevice.
9. Observe charging current by measuring the voltage
on IMON turret:the IMON voltage should be equal to
0.46V/A in proportion to the IBUS load current.
Table1. Common USB Charger Profiles and Corresponding
SELPins
SEL1 SEL2 SEL3 CHARGER PROFILE DESCRIPTION
State 21 LOW TRI HIGH USB BC 1.2 DCP Profile
State 22 TRI TRI HIGH 2.0A Vendor Charger Profile
State 24 LOW HIGH HIGH 2.4A Vendor Charger Profile

9
DEMO MANUAL DC2688A
Rev. 0
Figure9. Proper Measurement Equipment Setup for Evaluating Common USB Charger Profiles
QUICK START PROCEDURE

10
DEMO MANUAL DC2688A
Rev. 0
EVALUATE USB BC 1.2 CDP APPLICATIONS
The LT8698S/LT8698S-1 integrates necessary hardware
to support USB BC 1.2 Charging Downstream Port (CDP)
charger profile which allows compliant devices to draw
high current of up to 1.5A from V
BUS
while simultane-
ously communicating with the host at USB high speed
of 480Mbps.
Refer to Figure10 for proper measurement equipment
setup and follow the procedure below.
1. Check that JP6 is placed on the ON position to ensure
that the 3.3V LDO is enabled.
2. Select JP2 and JP3 to be in the LOW position and
select JP4 to be in the LOW or TRI position. Select
JP4 SEL3 in the LOW position sets the LT8698S/
LT8698S-1 in select state 0 which performs the
CDP sequence with the data line switches closed
and without termination. Select JP4 SEL3 in the TRI
position sets the LT8698S/LT8698S-1 in select state
1 which performs the CDP sequence with the data line
switches open and 20k termination resistors tied from
HD+ and HD–to GND. Both select0 and select 1 are
valid state in which to start the CDP sequence. For
further information about the CDP sequence, please
refer to the LT8698S/LT8698S-1 datasheet.
3. With power off, connect the input power supply to
VEMI and GND turrets. If the EMI/EMC performance
is not important, connect the input power supply to
VIN and GND turrets.
4. Check that JP1 EN jumper is placed on the ONposition.
5. Turn on the power at the input.
NOTE:Make sure that the input voltage never
exceeds42V.
6. Check for proper output voltages:V
BUS
= 5V, and D11
LED indicator lights up in green.
7. Plug a USB cable connecting to a PC with type B
connector to the typeB socket of the DC2688A demo
board and connect the USB cable to a computer.
8. Check the STATUS pin voltage and observe STATUS
yellow LED is on, meaning STATUS pin is low. At this
point, the LT8698S/LT8698S-1 puts a 100μA current
source on the D+, asserts STATUS low and waits for
a portable device to attach to the USB socket.
9. Attach a CDP compliant portable device to the type A
socket of the DC2688A demo board.
10. Observe the CDP negotiation between the porta-
ble device and the computer. You may monitor the
voltage waveforms on STATUS, VBUS, IMON point,
D+, and D–during this CDP negotiation. Observe the
USB data connection between portable device and
the PC as manifested by the portable device showing
up in the PC in “devices and driver”or “this PC”,
and the PC may be able to access data stored in the
portabledevice.
11. To restart another CDP session, perform the
followingsteps:
a. Unplug the portable device from the type A socket.
b. Place the JP1 EN jumper to OFF position and then
place it back to ON position. Cycling the EN/UV pin
of the LT8698S/LT8698S-1 resets the CDP state
machine which is necessary in order to restart
another CPD sequence. Alternatively, the CDP state
machine can be reset by setting LT868S to a non-
CDP state (any select state other than state 0, state
1, and state 2) and coming back to state 0 or state
1. Note:in an actual CDP application, a USB host
microcontroller can detect a portable device detach
and reset the DP machine by controlling the SEL
pin(s).
c. Repeat from step 8.
QUICK START PROCEDURE

11
DEMO MANUAL DC2688A
Rev. 0
QUICK START PROCEDURE
Figure10. Proper Measurement Equipment Setup for Evaluating USB CDP Charger Profiles

12
DEMO MANUAL DC2688A
Rev. 0
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 3 C3, C39, C45 CAP., 1μF, X5R, 50V, 10%, 0603 TDK, CGA3E3X5R1H105K080AB
2 3 C4, C5, C63 CAP., 0.01μF, X5R, 25V, 10%, 0603 TDK, C1608X7R1E103K080AA
3 1 C6 CAP., 10μF, X5R, 10V, 10%, 0805 MURATA, GRM21BR61A106KE19L
4 8 C18, C35, C37, C51, C53, C54,
C55, C64
CAP., 0.1μF, X7R, 25V, 10%, 0603 TDK, C1608X7R1E104K080AA
5 1 C19 CAP., 2.2μF, X5R, 25V, 10%, 0603 MURATA, GRM188R61E225KA12D
6 1 C22 CAP., 100μF, ALUM. ELECT., 25V, 20%, 6.3mm × 7.7mm
SMD, D8
PANASONIC, EEHZA1E101XP
7 2 C23, C24 CAP., 18pF, NP0, 25V, 10%, 0402 AVX, 04023A180KAT2A
8 5 C25, C27, C29, C32, C34 CAP., 1000pF, X7R, 25V, 10%, 0402 AVX, 04023C102KAT2A
9 2 C26, C31 CAP., 1μF, X5R, 16V, 10%, 0402 TDK, C1005X5R1C105K050BC
10 5 C28, C30, C33, C48, C50 CAP., 0.1μF, X5R, 25V, 10%, 0402 AVX, 04023D104KAT2A
11 1 C36 CAP., 1000pF, C0G, 25V, 10%, 0603 AVX, 06033A102KAT2A
12 1 C47 CAP., 4700pF, X7R, 25V, 10%, 0603 MURATA, GRM188R71E472KA01D
13 1 C49 CAP., 1μF, X5R, 10V, 10%, 0603 MURATA, GRM188R61A105KA61D
14 1 C56 CAP., 1μF, X5R, 25V, 10%, 0603 MURATA, GRM188R61E105KA12D
15 1 C58 CAP., 1μF, X5R, 25V, 10%, 0402 MURATA, GRM155R61E105KA12D
16 1 C59 CAP., 10μF, TANT., 16V, 10%, 3216, 1Ω, TPSA AVX, TPSA106K016R1000
17 1 C60 CAP., 4.7μF, X7R, 25V, 10%, 0805 MURATA, GRM21BR71E475KA73L
18 2 C61, CVIN1 CAP., 4.7μF, X7R, 50V, 10%, 1206 MURATA, GRM31CR71H475KA12L
19 1 C62 CAP.,1000pF, C0G, 50V, 5%, 0603 MURATA, GRM1885C1H102JA01D
20 1 COUT1 CAP., 22μF, X7R, 25V, 20%, 1210 MURATA, GRM32ER71E226ME15L
21 2 D1, D13 LED, GREEN, DIFFUSED, 0603 BROADCOM, HSMG-C190
22 1 D3 LED, RED, NON-DIFFUSED, 1208, PLCC-2, VISHAY, VLMS30K1L2-GS08
23 1 D4 LED, YELLOW, NON-DIFFUSED, 1208, PLCC-2, VISHAY, VLMY30K2M1-GS08
24 2 D8, D9 DIODE, SCHOTTKY, 30V, 200mW, SOD-323 DIODES INC., BAT54WS-7-F
25 1 D11 LED, GREEN, NON-DIFFUSED, 3.0mm × 2.2mm
SMD, PLCC-2,
VISHAY, VLMC3101-GS08
26 1 D12 DIODE, SCHOTTKY, 100V, 250mA, SOD-323F, AEC-Q101 NEXPERIA, BAT46WJ
27 1 J2 CONN., USB-A 2.0, RCPT, FEMALE, 4-POS, 1PORT,
R/A HORZ. SMT
WURTH ELEKTRONIK, 62900416021
28 1 J3 CONN., USB-B, RCPT, FEMALE, 4POS, 1PORT,
R/A HORZ, THT
WURTH ELEKTRONIK, 61400416121
29 2 JP1, JP5 CONN., HDR., MALE, 2×3, 2mm, VERT, STR, THT SAMTEC, TMM-103-02-L-D
30 3 JP2, JP3, JP4 CONN., HDR, MALE, 2×4, 2mm, VERT, STR, THT WURTH ELEKTRONIK, 62000821121
31 3 JP6, JP7, JP8 CONN., HDR, MALE, 1×3, 2mm, VERT, STR, THT WURTH ELEKTRONIK, 62000311121
32 1 L1 IND., 2.2μH, PWR. SHIELDED, 20%,
5.48mm × 5.28mm, AEC-Q200
COILCRAFT, XFL5030-222MEB
33 4 L2, L3, L4, L5 IND., 10nH, HIGH-Q, 3%, 0201, AEC-Q200 TDK, MLG0603P10NHTD25
34 1 R1 RES., 866Ω, 1%, 1/10W, 0603, AEC-Q200 VISHAY, CRCW0603866RFKEA
35 2 R9, R25 RES., 330Ω, 1%, 1/10W, 0603, AEC-Q200 VISHAY, CRCW0603330RFKEA
36 11 R10, R11, R19, R21, R24, R28, R29,
R32, R42, R44, R48
RES., 100k, 1%, 1/10W, 0603, AEC-Q200 VISHAY, CRCW0603100KFKEA

13
DEMO MANUAL DC2688A
Rev. 0
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
37 5 R15, R16, R51, R52, R53 RES., 4.99k, 1%, 1/10W, 0603, AEC-Q200 VISHAY, CRCW06034K99FKEA
38 1 R20 RES., 12k, 1%, 1/16W, 0402 VISHAY, CRCW040212K0FKED
39 2 R31, R34 RES., 2k, 1%, 1/10W, 0603, AEC-Q200 VISHAY, CRCW06032K00FKEA
40 13 R33, R36, R38, R39, R40, R41, R49,
R50, R55, R56, R65, R66, R67
RES., 10k, 1%, 1/10W, 0603, AEC-Q200 VISHAY, CRCW060310K0FKEA
41 1 R37 RES., 9.09k, 1%, 1/10W, 0603, AEC-Q200 VISHAY, CRCW06039K09FKEA
42 1 R47 RES., 200k, 1%, 1/10W, 0603 VISHAY, CRCW06039K09FKEA
43 1 R59 RES., 0Ω, 1/10W, 0603, AEC-Q200 VISHAY, CRCW06030000Z0EA
44 1 R61 RES., 1k, 1%, 1/10W, 0603, AEC-Q200 VISHAY, CRCW06031K00FKEA
45 2 R62, R63 RES., 20k, 1%, 1/10W, 0603 VISHAY, CRCW060320K0FKEA
46 1 R68 RES., 499k, 1%, 1/10W, 0603, AEC-Q200 VISHAY, CRCW06031K00FKEA
47 1 RSEN1 RES., 0.01Ω, 1%, 1/8W, 0805, SENSE, AEC-Q200 VISHAY, WSL0805R0100FEA
48 1 U2 IC, 2-PORT USB 2.0 HUB CONTROLLER, SQFN-24 MICROCHIP, USB2422T-I/MJ
49 1 U3 IC, MEMORY, EEPROM, 2Kb (256×8), TSSOP-8, 400kHz MICROCHIP, 24LC025
50 1 U4 IC, 500mA LDO LINEAR REGULATOR, MSOP-12 ANALOG DEVICES, LT3065HMSE-5
51 1 U5 IC, 200mA LDO LINEAR REGULATOR, MSOP-8 ANALOG DEVICES,
LT3063EMS8E-3.3#PBF
52 1 U6 IC, ADC/DAC, 8-CH, 12-BIT, LFCSP-16 ANALOG DEVICES, AD5593RBCPZ
53 1 Y1 CRYSTAL, 24.0000MHz, 6pF, 2.0mm × 1.6mm SMD MURATA, XRCGB24M000F3M00R0
DC2688A-A Version Specific Components
1 1 U1 IC, USB CHARGER, LQFN-32 ANALOG DEVICES, LT8698SEV#PBF
DC2688A-B Version Specific Components
1 1 U1 IC, USB CHARGER, LQFN-32 ANALOG DEVICES, LT8698SEV-1#PBF
Additional Demo Board Circuit Components
1 1 C8 CAP., 22μF, ALUM. ELECT., 63V, 20%, 6.3mm × 7.7mm,
CE-BS
SUN ELECTRONIC INDUSTRIES CORP,
63CE22BS
2 3 C38, C40, C43 CAP., 1μF, X5R, 50V, 10%, 0603 TDK, CGA3E3X5R1H105K080AB
3 2 C41, C42 CAP., 10μF, X5R, 50V, 10%, 1210 MURATA, GRM32ER61H106KA12L
4 0 COUT2 CAP., OPTION, 7343
5 2 CINV2, CINV3 CAP., 0.1μF, X7R, 50V, 10%, 0402 MURATA, GRM155R71H104KE14J
6 1 FB1 IND., 220Ω @ 100MHz, FERRITE BEAD, 25%, 3A,
40mΩ, 0805, AEC-Q200
TDK, MPZ2012S221ATD25
7 1 L6 IND., 0.47μH, PWR., 20%, 7A, 16mΩ,
1616BZ, IHLP-11 SERIES
VISHAY, IHLP1616BZERR47M11
8 0 R23, R27, R30, R35, R60 RES., OPTION, 0603
9 1 U4 IC, MEMORY, EEPROM, 2Kb (256x8), TSSOP-8, 400kHz MICROCHIP, 24LC025-I/ST
Hardware for Demo Board Only
1 9 E1, E2, E5, E6, E7, E8, E9, E10, E11 TEST POINT, TURRET, 0.094" MILL-MAX, 2501-2-00-80-00-00-07-0
2 1 J4 CONN., SHROUDED HDR, MALE, 2×7, 2mm,
VERT, STR, THT
MOLEX, 87831-1420
3 4 MP1, MP2, MP3, MP4 STANDOFF, NYLON, SNAP-ON, 0.375" KEYSTONE, 8832
4 7 XJP1, XJP2, XJP3, XJP4, XJP5,
XJP6, XJP7
CONN., SHUNT, FEMALE, 2-POS, 2mm SAMTEC, 2SN-BK-G
5 1 XJP8 CONN., SHUNT, FEMALE, 2-POS, 2mm WURTH ELEKTRONIK, 60800213421

14
DEMO MANUAL DC2688A
Rev. 0
SCHEMATIC DIAGRAM
5
5
4
4
3
3
2
2
1
1
D D C C B B A A
LDO3.3V
GPIO IN GPIO IN
GPIO OUT
GPIO OUT GPIO OUT
analog IN
Tol. ±1.0%
Tol. ±1.0%
7-bit I2C address: 0010000b (10h)
LDO5V
GPIO IN
VCC
VCC
VCC
VEMI
VEMI
EXT_SEL3 EXT_SEL2 EXT_SEL1
SUS_IND
VBUS
IMON_IN
/FLT
STATUS
SCL SDA
V3V3
V5V_LDO
VCC
V5V_IN
V5V_LDO
C60 4.7uF 0805 25V
R62
20k
R51
4.99k
+
C59
10uF
321616V
U5
LT3063‐MS8E‐3.3
IN
5
IN
6OUT 3
OUT 4
BYP 1
ADJ 2
/SHDN
7
GND
8
GND
9
C62 1000pF 50V
D1
GREEN
HSMG‐C190
JP6
ON
OFF
LDO3.3V
1 3 2
C64 0.1uF
C3 1uF
50V
LT3065HMSE‐5 U4
IN1
1
IN2
2
SHDN
3
PWRGD
4
IMAX
5
NC
6NC
7
REF/BYP
8
ADJ 9
SENSE 10
OUT2 11 OUT1 12
GND
13
J4
QuikEval
MOSI/SDA 7
EESDA 9
V+ 1
5V 2
CS 6
SCK/SCL 4
EEVCC 10
MISO 5
EESCL 11
EEGND 12
AUX 14
GND
3
GND
13
GND
8
C53 0.1uF
C5
0.01uF
C61 4.7uF 1206 50V
R49
10k
JP7
ON
OFF
LDO5V
1 3 2
R61
1k
R47
200k
R63
20k
D8
BAT54WS
D9
BAT54WS
R52 4.99k
R59
0
R48 100k
D12
BAT46WJ
2 1
C55 0.1uF
U3 24LC025‐I/ST
SDA 5
VCC 8
A0
1
A1
2
A2
3
VSS
4
WP 7 SCL 6
C54 0.1uF
C51 0.1uF
C4
0.01uF
C6
10uF
R1
866
R60 OPT
D13
GREEN
HSMG‐C190
C63
0.01uF
25V
U6
AD5593R
VDD
1
I/O0
2
I/O3
5
VREF
6
VLOGIC
7
I/O4
8
I/O5 9 I/O6 10 I/O7 11
GND 12
SDA 13
SCL 14
RESET 15
I/O1
3
I/O2
4
A0 16
R50 10k
R68 499k
V3V3
LDO_IN

15
DEMO MANUAL DC2688A
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog
Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications
subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
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 0603 2. All Capacitors 0402/0603
ClosetoIC.Lvl2
VBUS(1)
D‐(2)D+(3)
GND(4)
SHLD(5) SHLD(6)
USB‐B Reference
VBUS(1)
D‐(2)
D+(3)
GND(4)
SHLD(5) SHLD(6)
USB‐A Reference
ON
OFF
DIV
Close to IC
VBUS
EN
VERSIONTABLE
ASSYVERSION
DC2688A‐A DC2688A‐B
LT8698S LT8698S‐1
U1
0.1uF
OPT
CVIN2
0.1uF
OPT
CVIN3
*
*
**
INTVCC
INTVCC
INTVCC INTVCC INTVCC INTVCC
VIN VIN
VEMI
EXT_SEL1
EXT_SEL2
EXT_SEL3
V5V_IN
VBUS_DET
STATUS
IMON
VBUS
/FLT
V3V3
SUS_IND
IMON IMON_IN
Y1
24.0000MHz
E10 IMON
C33 0.1uF 0402
R38 10k L4 10nH
0201
MLG0603P10NHTD25
R10
100k
R30
OPT
U1
LD‐
13
/FLT
4
BST 26
EN/UVLO
3
SEL3
8
SEL1
6
STATUS
5
SW 25
PGND 27
HD‐
15
SW 24
VIN 29
GND 23
OUT/ISP 22
GND
1
BUS/ISN 21
USB5V 20
VIN 30
CLAMP 18
VCC
2
RT
9
SYNC
10
GND
11
RCBL 19
GND
14
HD+
16
SEL2
7
LD+
12
GND 17
PGND 32
GND
33
GND
34
GND
35 GND 36
GND 37
R27
OPT
C27
1000pF
0402
R25 330
C18 0.1uF
E2
GND
R66 10k
+
C8 22uF
63V 63CE22BS
RSEN1 0.01 WSL0805R0100FEA
JP8
ON OFF
IMONA/D
1
3
2
R16 4.99k
JP2
Z
SEL1
HI
µC
LO
1 3 5 6
4 2
7 8
C36 1000pF
E5
/FLT
C49 1uF 10V
+
COUT2
OPT 7343
C50
0.1uF
0402
25V
C56
1uF
25V X5R
E7
VEMI
6V‐42V
R36 10k
C26 1uF
E6
STATUS
C42
10uF
50V
1210
C47 4700pF
C45 1uF 0603
R11 100k
E1
VIN
6V‐42V
R28
100k
R9 330
C38
1uF
50V
C30 0.1uF
R41 10k
L6 0.47uH IHLP1616BZERR47M11
C41
10uF
50V
1210
CVIN1 4.7uF
1206
50V
U2
USB2422
VBUS_DET
16
USBUP_DM
19
USBUP_DP
20
SMBCLK
14
SMBDATA
13
SUSP_IND
17
RESET_N
15
RBIAS
24
XTALIN
22
XTALOUT
21
VSS 25
USBDN1_DP 3
USBDN1_DM 2
USBDN2_DP 5
USBDN2_DM 4
OSC1 8
OSC2 12
PRTPWR1 7
PRTPWR2 11
PLLFILT
23
CRFILT 10
VDDA33
18 PLLREF/VDDA3 1
REG/VDDA33 9
TEST 6
C34
1000pF
0402
R39 10k
R19
100k
COUT1 22uF 25V 1210 X7R
JP1
1 3 5 6
4 2
L5 10nH
0201 MLG0603P10NHTD25
CVIN2
0402
E11
EXT_SYNC
C31 1uF
C39
1uF
R56 10k
R24
100k
C25
1000pF
J2
USB‐A2.0
62900416021
1 2 3 4 5 6
R44 100k
R35
OPT
C37 0.1uF
R29 100k
J3
USB‐B
61400416121
1
2
3
4
5
6
E8
VBUS
5V/2.5A
C29
1000pF
D3 RED
VLMS30K1L2‐GS08
21
R31
2k
C43 1uF
50V
R23
OPT
JP3
Z
SEL2
HI
µC
LO
1 3 5 6
4 2
7 8
C35 0.1uF
JP4
Z
SEL3
HI
µC
LO
1 3 5 6
4 2
7 8
R67 10k
+
C22
100uF
25V
EEHZA1E101XP
12
R34
2k
L1 2.2uH
XFL5030‐222MEB
R53
4.99k
R21 100k
C24
18pF 0402
L2
10nH 0201
MLG0603P10NHTD25
R55 10k
D11 GREEN
VLMC3101‐GS08
2 1
FB1
MPZ2012S221ATD25
R42 100k
R33 10k
JP5
SYNC
FCMW/SSM PSK FCMW/OSSMorSYNC
1 3 5 6
4 2
C28
0.1uF 0402
CVIN3
0402
C19
2.2uF
C58 1uF
0402
25V
R65 10k
R37 9.09k
R15 4.99k
R32 100k
C40
1uF
50V
E9 GND
R40 10k
R20
12k
0402
D4 YELLOW
VLMY30K2M1‐GS08
21
L3
10nH 0201
MLG0603P10NHTD25
C48
0.1uF
25V
0402
C32
1000pF
C23
18pF
0402
INTVCC
RT CLAMP
RCBL USB5V VBUS OUT/ISP
IMON
VBUS_DET
/FLT
STATUS
HD‐
V3V3
V3V3
SUS_IND
VBUS
V3V3
V5V_IN
V3V3
VBUS_DET
HD+
USBUP_DM
USBUP_DP
ENUVLO
SYNC
SEL2 SEL1
V3V3
SEL3
V3V3

16
DEMO MANUAL DC2688A
Rev. 0
 ANALOG DEVICES, INC. 2021
02/21
www.analog.com
ESD Caution
ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protection
circuitry, damage may occur on devices subjected to high energy ESD. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of functionality.
Legal Terms and Conditions
By using the evaluation board discussed herein (together with any tools, components documentation or support materials, the “Evaluation Board”), you are agreeing to be bound by the terms and
conditions set forth below (“Agreement”) unless you have purchased the Evaluation Board, in which case the Analog Devices Standard Terms and Conditions of Sale shall govern. Do not use the Evaluation
Board until you have read and agreed to the Agreement. Your use of the Evaluation Board shall signify your acceptance of the Agreement. This Agreement is made by and between you (“Customer”)
and Analog Devices, Inc. (“ADI”), with its principal place of business at One Technology Way, Norwood, MA 02062, USA. Subject to the terms and conditions of the Agreement, ADI hereby grants to
Customer a free, limited, personal, temporary, non-exclusive, non-sublicensable, non-transferable license to use the Evaluation Board FOR EVALUATION PURPOSES ONLY. Customer understands and
agrees that the Evaluation Board is provided for the sole and exclusive purpose referenced above, and agrees not to use the Evaluation Board for any other purpose. Furthermore, the license granted
is expressly made subject to the following additional limitations:Customer shall not (i) rent, lease, display, sell, transfer, assign, sublicense, or distribute the Evaluation Board;and (ii) permit any Third
Party to access the Evaluation Board. As used herein, the term “Third Party”includes any entity other than ADI, Customer, their employees, affiliates and in-house consultants. The Evaluation Board is
NOT sold to Customer;all rights not expressly granted herein, including ownership of the Evaluation Board, are reserved by ADI. CONFIDENTIALITY. This Agreement and the Evaluation Board shall all
be considered the confidential and proprietary information of ADI. Customer may not disclose or transfer any portion of the Evaluation Board to any other party for any reason. Upon discontinuation of
use of the Evaluation Board or termination of this Agreement, Customer agrees to promptly return the Evaluation Board to ADI. ADDITIONAL RESTRICTIONS. Customer may not disassemble, decompile
or reverse engineer chips on the Evaluation Board. Customer shall inform ADI of any occurred damages or any modifications or alterations it makes to the Evaluation Board, including but not limited
to soldering or any other activity that affects the material content of the Evaluation Board. Modifications to the Evaluation Board must comply with applicable law, including but not limited to the RoHS
Directive. TERMINATION. ADI may terminate this Agreement at any time upon giving written notice to Customer. Customer agrees to return to ADI the Evaluation Board at that time. LIMITATION OF
LIABILITY. THE EVALUATION BOARD PROVIDED HEREUNDER IS PROVIDED “AS IS”AND ADI MAKES NO WARRANTIES OR REPRESENTATIONS OF ANY KIND WITH RESPECT TO IT. ADI SPECIFICALLY
DISCLAIMS ANY REPRESENTATIONS, ENDORSEMENTS, GUARANTEES, OR WARRANTIES, EXPRESS OR IMPLIED, RELATED TO THE EVALUATION BOARD INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTY OF MERCHANTABILITY, TITLE, FITNESS FOR A PARTICULAR PURPOSE OR NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS. IN NO EVENT WILL ADI AND ITS
LICENSORS BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES RESULTING FROM CUSTOMER’S POSSESSION OR USE OF THE EVALUATION BOARD, INCLUDING
BUT NOT LIMITED TO LOST PROFITS, DELAY COSTS, LABOR COSTS OR LOSS OF GOODWILL. ADI’S TOTAL LIABILITY FROM ANY AND ALL CAUSES SHALL BE LIMITED TO THE AMOUNT OF ONE
HUNDRED US DOLLARS ($100.00). EXPORT. Customer agrees that it will not directly or indirectly export the Evaluation Board to another country, and that it will comply with all applicable United States
federal laws and regulations relating to exports. GOVERNING LAW. This Agreement shall be governed by and construed in accordance with the substantive laws of the Commonwealth of Massachusetts
(excluding conflict of law rules). Any legal action regarding this Agreement will be heard in the state or federal courts having jurisdiction in Suffolk County, Massachusetts, and Customer hereby submits
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