Linear Technology DC1717A Quick setup guide

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dc1717afa
DEMO MANUAL DC1717A
Description
LTC4417
Prioritized PowerPath™ Controller
Demonstration circuit DC1717A uses the LT C
®
4417 to
arbitrate between three input supply rails,selecting the
highest priority,valid supply to power the load.The rail’s
priority is defined by the input connection (V1-V3). Each
rail has overvoltage and undervoltage thresholds set by
external resistors.If the highest priority rail voltage falls
out of the defined window (overvoltage or undervoltage),
the rail with the next highest priority,which is valid,is
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
performance summary
Specifications are at TA= 25°C
enabled and powers the load.Two or more LTC4417s
can be cascaded to provide switchover between more
than three rails.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1717A
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V1-V3, VOUT V1 to V3, VOUT Operating Supply Range 2.5 36 V
ΔVGOpen (VS-VG) Clamp Voltage VOUT = 11V, G1 to G3 = Open 5.4 6.2 6.7 V
ΔVG(SOURCE) Sourcing (VS-VG) Clamp Voltage VOUT = 11V, I = –10µA 5.8 6.6 7 V
ΔVG(SINK) Sinking (VS-VG) Clamp Voltage VOUT = 11V, I = 10µA 4.5 5.2 6 V
ΔVG(OFF) G1 to G3 Off (VS-VG) Threshold V1 = V2 = V3 = 2.8V, VOUT = 2.6V, G1 to G3 Rising Edge 0.12 0.35 0.6 V
ΔVG(SLEW,ON) G1 to G3 Pull-Down Slew Rate VOUT = 11V, CGATE = 10nF 4 9 20 V/µs
ΔVG(SLEW,OFF) G1 to G3 Pull-Up Slew Rate VOUT = 11V, CGATE = 10nF 7.5 13 22 V/µs
IGATE(LOW) G1 to G3 Low Pull-Down Current VOUT = 2.6V, V1 to V3 = 2.8V, (G1 to G3) = ΔVG+ 300mV 0.8 2 7 µA
VREV Reverse Voltage Threshold Measure (V1 to V3) – VOUT, VOUT Falling 30 120 200 mV
tG(SWITCHOVER) Break-Before-Make Time VOUT = 11V, CGATE = 10nF 0.7 2 3 µs
VVALID(OL) VALID1 to VALID3 Output Low Voltage I = 1mA, (V1 to V3) = 2.5V, VOUT = 0V 0.2 0.55 V
tPVALID(OFF) VALID1 to VALID3 Delay OFF from
OV/UV Fault
5 8 13 µs
VSHDN(THR) SHDN Threshold Voltage SHDN Rising 0.4 0.8 1.2 V
VSHDN_EN(HYS) SHDN, EN Threshold Hysteresis 100 mV
ISHDN_EN SHDN, EN Pull-Up Current SHDN = EN = 0V –0.5 –2 –5 µA
VOV_UV(THR) OV1 to O3, UV1 to UV3 Comparator
Threshold
VOUT = 11V, OV1 to OV3 Rising, UV1 to UV3 Falling 0.985 1 1.015 V
VOV_UV(HYS) OV1 to O3, UV1 to UV3 Comparator
Hysteresis
VOUT = 11V 15 30 45 mV
tVALID V1 to V3 Validation Time 100 256 412 ms
V1 Operating Voltage of Channel V1 9.6 12 14.4 V
V2 Operating Voltage of Channel V2 4 5 6 V
V3 Operating voltage of Channel V3 6.4 8 9.6 V
ILOAD Load Current 2 A
AVI Auxiliary Voltage Input 6 24 V

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DEMO MANUAL DC1717A
overview
operating principles
The LTC4417 controls three sets of external back-to-back
P-channel MOSFETs to connect the proper rail to the
load. Precision comparators are used to monitor each of
the three input rails for both UV and OV conditions.The
highest priority input supply whose voltage is within its
respective OV/UV window for at least 256ms is consid-
ered valid and connected to the load.Low signals on the
VALID1, VALID2,and VALID3 pins indicate validation of
the V1, V2, and V3 voltages.
DC1717A is designed to operate from inputs of 12V,
5V, and 8V, applied to V1, V2and V3respectively.The
valid range of each supply is ±20%, as set by OV and UV
comparators and their associated resistive dividers.V1
has the highest priority,V3has the lowest.The highest
priority input that is also within its valid range is selected
to power the output.V1, V2and V3inputs are protected
against input glitches of up to ±42V. Maximum load cur-
rent is 2A, limited by MOSFET capability.
Logic and LEDs are included to provide visual information
about the operating status.These circuits are powered
from a 6V to 24V auxiliary voltage input (AVI)which is
regulated by an LT3060 (U4) to 5V. This auxiliary 5V rail
also powers 100kΩ pull-ups for VALID pins.AVI must be
present in order for the board to operate.See the Modifica-
tion section for a means of eliminating AVI.
To eliminate back-and-forth switching during rail switcho-
ver,theLTC4417providesa30mVhysteresisintheOVand
UVcomparators,andanexternallyadjustablecurrentmode
hysteresis using the OV/UV resistive dividers.DC1717A’s
input reference hysteresis is 6%, and can be changed to
3% by moving the JP1 jumper to the 30mV position.
The controller’s “break-before-make” switching method
prevents cross conduction between input channels and
reverse current from the output capacitor into the selected
input supply.
Each channel’s control circuit of the LTC4417 has a REV
comparator, which monitors the connecting input supply
and output load voltage.The REV comparator delays the
connection until the output voltage droops 120mV below
the input voltage. This prevents reverse current.
TheLTC4417has two common control pins:EN andSHDN.
Pulling the EN pin below 1V turns off all external back-to-
back P-channel MOSFETs.When this pin is driven above
1V, the highest priority valid channel is connected to the
load. All these actions are provided without resetting the
256ms OV/UV timers.
Pulling the SHDN pin below 0.8V turns off all external
back-to-back P-channel MOSFETs,placing the controller
in a low current state and resetting the 256ms timers
used to validate input rail voltages.It requires at least
256ms to validate each rail voltage after the SHDN pin
signal goes high.
The LTC4417 features two different driving modes for the
P-channel MOSFET gates.
One mode is provided by the internal soft-start circuitry,
which limits output voltage slew rate to no more than
5V/ms.Asthehighestoutput voltageslewrate,usually,can
impose the highest requirements for circuit components,
5V/ms should be taken into account as a worst case for
component selection.
The soft-start circuitry is enabled each time under the
following conditions:
• If the LTC4417 is first powered on, or
• If SHDN is forced low, or
• If VOUT falls below ~0.7V
Soft-start is disabled when:
• any channel turns off,including the channel that is soft
starting.
• 32ms validation delay time has elapsed during the soft-
start interval.

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DEMO MANUAL DC1717A
Design proceDure for moDification of Dc1717a
operating principles
The other driving mode of the P-channel MOSFETs is used
inthevoltageswitching operation,when the higher priority
rail replaces the rail losing validity.The gate driver oper-
ates with a fixed current,which is defined by the external
component parameters RSand CSshown in Figure 1.
The LTC4417 circuit designer should select the value of
RSand CSbased on the MOSFET parameters,power rail
source characteristics,acceptable output voltage droop
during transient, and the value of load capacitance.
CIN1
68µF CS
VS1
LTC4417
G1 VOUT VOUT
RS
DS
BAT54
12V WALL
ADAPTER
V1 IRF7324
M1 M2
+
CL
47µF
+
CVS1
Figure 1
The valid input range for any supply is controlled by the
OV and UV comparators with resistive dividers (R4-R13).
See the LTC4417 data sheet for design equations to select
resistors to match a particular requirement.
DualMOSFETs,Q1-Q3,maybe replaced with singledevices
Q4-Q9 by simply removing Q1-Q3. Pads for Q4-Q9 are
located on the bottom side of the board.
The requirement for AVI may be eliminated by removing
jumpers JP2and JP3, and removing resistor R19. This
modification leaves the LEDs unpowered and the inputs
of U2and U3clamp the VALID pins at 0.7V, but otherwise
leaves the LTC4417 operating autonomously.
The following design considerations and equations dem-
onstrate the interrelation of the main component values
and transient parameters in the rail transitions,when the
output voltage exceeds 0.7V. The variables CSand RS
used in the design equations correspond to the following
board components:
• C20, R23 for V1 (+12V channel)
• C21, R26 for V2 (+5.0V channel)
• C22, R28 for V3 (+8.0V channel)
Tohavedominantinfluenceonthetransienttime CSshould
be at least ten times larger than the P-channel MOSFET’s
reverse transfer capacitance (Miller). In this design,for
all rails, CS(C20, C21,and C22) equals 47nF.
The slew rate of the output voltage can be expressed as
a function of CS:
dV
OUT
dt =
dV
CS
dt =
V
SINK
– | V
THRES
|
R
S
•C
S
(1)
where:
• VSINK is the LTC4417 parameter rated in the data sheet
as ∆VG(SINK) = 4.5V-6V.
• VTHRES is the P-channel gate threshold voltage,which
is between –1.5V and –3.5V for the Si7905DN installed
on the board.
• RS= 249Ω and CS= 47nF.
Given that dVOUT/dt is based on the transient time require-
ment, it is possible to define RSfrom equation 1.
Theoutputvoltageslewrate,dVOUT/dt,rangeforthecircuit
withthelistedparametersisbetween 85V/msand385V/ms.
During the transition of rails,the load can be disconnected
from any rail for a time:
TDISCON = tG(SWITCHOVER) + tpVALID(OFF) + tGATE_THRES
Twofirst summands of theTDISCON arerated intheLTC4417
data sheet as:
tG(SWITCHOVER) = (0.3 to 3)µs
tpVALID(OFF) = (5 to 13)µs

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dc1717afa
DEMO MANUAL DC1717A
The second summand,tpVALID(OFF),should be taken into
account if the associated LTC4417 input does not have
any bypass capacitor and the rail can be disconnected
from the input instantly.
The third one must be calculated as:
tGATE_ THRES =RS•CS–In 1– VTHRES
VSINK
⎛
⎝
⎜⎞
⎠
⎟
⎡
⎣
⎢
⎤
⎦
⎥
(2)
It is possible to determine the minimum capacitive load
required to hold the output up during switchover as a:
CLOAD(MIN) ≥
I
LOAD(MAX)
•T
DISCON
VOUT(DROOPMAX)
(3)
where:
• ILOAD(MAX) is the maximum load current, A
• VOUT(DROOPMAX) is the maximum acceptable voltage
droop, V
Design proceDure for moDification of Dc1717a
R
S•CS–In 1– VTHRES
VSINK
⎛
⎝
⎜⎞
⎠
⎟
⎡
⎣
⎢⎤
⎦
⎥=10µs
Calculate RSwith CL(INIT)
Recalculate CL with RS
Done.
Use CL(INIT) and RS
No
Is recalculated CL
lower than initial
CL(INIT)?
As shown in the equation (3), the use of external slew rate
control will add additional delay to the total switchover
time. Unfortunately,the actual components cannot be
chosen until the load capacitance is known.This circular
issue can only be resolved through an iterative process.
Theprocess starts by calculating the CLOAD(MIN),assuming
thattGATE_THRES =10μs.For clarity this valuewill be labeled
CLOAD(INIT).Using the calculated CLOAD(INIT),calculate RS
from the expression of the TDISCON.To ensure the newly
calculated RSbased on CLOAD(INIT) is sufficient,calculate
CLOAD with the calculated RS.
If CLOAD(INIT) (the initial calculated CLOAD)is higher than
the newly calculated CLOAD then the process is completed.
If the CLOAD(INIT) is lower than the newly calculated CLOAD,
calculateRSusing the highervalueand repeat thisprocess.
Figure 2

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dc1717afa
DEMO MANUAL DC1717A
turrets
Jumpers
leDs
V1: 12V supply input; do not exceed ±42V.
V2: 5V supply input; do not exceed ±42V.
V3: 8V supply input; do not exceed ±42V.
GND: Adjacent ground connection for input supplies.
VOUT: Output for up to 2A load.
GND: Adjacent ground connection for load.
AVI:Auxiliary Voltage Input. 6V to 24V input regulated
by U4to 5V for LEDs,logic and pull ups on various pins.
GND: Adjacent ground connection for auxiliary supply.
5V: 5V regulated output provided by U4, for powering
logic, LEDs and pull ups.Use this turret to verify that 5V
is present.
Each of the following turrets is a direct connection to the
like-name LTC4417 pin:
VALID1: pulled up with 100kOhm to auxiliary 5V supply.
VALID2: pulled up with 100kOhm to auxiliary 5V supply.
VALID3: pulled up with 100kOhm to auxiliary 5V supply.
EN: pulled up by 2μA internal to the LTC4417. Optional
R33 may be added as a pull-up to the auxiliary 5V power
supply.
SHDN:pulled up by 2μA internal to the LTC4417. Optional
R36 may be added as a pull-up to the auxiliary 5V power
supply.
CAS: used to cascade a second DC1717A. Connect the
CAS turret of the high priority DC1717A to the EN turret
of the lower priority DC1717A.
Grounds must be connected in common.
JP1, HYS:Add 30mV fixed hysteresis to the OV and UV
comparators, or 3% referred to actual supply input.In the
RHYS position input-referred hysteresis is set to 6.4%, as
controlled by R11. Default stuffing position is for 30mV.
JP2, EN:Directly controls EN pin.Default stuffing position
is ON, pulled up by internal 2μA current source.
No more than one of D8, D9and D10 will be illuminated
at any given moment:
D8: indicates power is being taken from V1.
D9: indicates power is being taken from V2.
D10: indicates power is being taken from V3.
D11, D16 and D17 indicate the presence of a valid input
on any of the three supplies:
D17: V1 is 12V±20%.
D11: V2 is 5V±20%.
D16: V3 is 8V±20%.

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dc1717afa
DEMO MANUAL DC1717A
Quick start proceDure
Refer to the Figure 3for proper measurement equipment
setup and follow the procedure below:
Initially, the LTC4417 should be disabled by:
• placing the jumper JP2 (EN) header in the OFF position,
and
• placing the jumper JP3 (SHDN)header in the OFF
position
Connecting the auxiliary power source (6V to 24V) to
the DC1717A (AVI and GND turrets)lights the green LED
(LDO-D12) indicating the presence of auxiliary +5V supply
for powering logic.
With power off,connect three power supplies with output
voltages of 12V, 5V, and 8V to corresponding DC1717A
turrets or banana jacks V1(+12V), V2(+5V), V3(+8V),
and GND.
Connect 6Ω load resistor (30W) to the DC1717A output
turret or banana jack (VOUT). Do not use an electronic
load in constant current mode.
Turn on three power supplies.No additional LEDs should
light.
Change the jumper JP3 (SHDN)header position from
OFF to ON.Three LEDs (VALID1, VALID2,and VALID3)
validating the input rail voltages should light.
Placing the jumper JP2 (EN) in the ON position turns on
the LTC4417 powering the load with 12V (2.0A). In an
initial power up the LTC4417 uses a fixed slew rate for the
output voltage, which should be not larger than 5V/ms.
Theprioritizingfunctionisdemonstrated by simply turning
off one or two of the V1, V2and V3supplies.The output
will be powered from the remaining supply of the high-
est priority.V1, V2and V3may be adjusted up and down
beyond ±20% to invalidate a given input.
6Ω
RESISTIVE
LOAD
12V
POWER
SUPPLY
5V
POWER
SUPPLY
8V
POWER
SUPPLY
Figure 3

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dc1717afa
DEMO MANUAL DC1717A
parts list
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
1 0 C1, C3, C5, C8 CAP., 1206 OPT
2 0 C2, C4, C6, C9 CAP., 2220 OPT
3 1 C7 CAP., ALUM., 47µF 50V 20% SMT SUN ELECT., 50CE47BS
4 5 C10, C11, C12, C13, C15 CAP., X5R, 1µF 50V, 10%, 0603 MURATA, GRM188R61H105KAALD
5 1 C14 CAP., X5R 10µF 10V 20% 0805 TAIYO YUDEN LMK212ABJ106MG -T
6 1 C16 CAP., NPO 10nF 50V 5% 0805 NIC, NMC0805NPO103J50TRPF
7 3 C17, C18, C19 CAP., X5R 0.1µF 50V 10% 0805 TAIYO YUDEN UMK212BJ104KG-T
8 3 C20, C21, C22 CAP., X7R 0.047µF 50V, 10%, 0805 MURATA, GRM21BR71H473KA01L
9 3 D1, D2, D3 DIODE, TVS BI-DIRECTIONAL, 26V, 600W DIODES/ZETEX SMBJ26CA-13-F
10 0 D7 ZENER DIODE, 5.1V SOD-123 OPT
11 8 D8-D12, D16, D17, D18 LED, GREEN, LED-ROHM-SML-01 ROHM, SML-012P8TT86
12 3 D13, D14, D15 DIODE, SCHOTTKY, SOD323 VISHAY SEMI., BAT42WS-E3-08
13 9 E1-E4, E6, E13-E16 TURRET, 0.094" MILL-MAX 2501-2-00-80-00-00-07-0
14 6 E7, E8, E9, E10, E11, E12 TURRET, 0.063" MILL-MAX 2308-2-00-80-00-00-07-0
15 3 JP1, JP2, JP3 HEADERS, SGL. ROW 3 PINS 2mm CTRS. SAMTEC TMM-103-02-L-S
16 3 SHUNTS ON JP1-JP3 (1&2) SHUNT, 2mm CTRS. SAMTEC 2SN-BK-G
17 6 J1, J2, J3, J4, J5, J6 JACK, BANANA KEYSTONE 575-4
18 3 Q1, Q2, Q3 DUAL P-CHAN., 40V POWERPAK1212-8-DUAL VISHAY Si7905DN-T1-GE3
19 0 Q4, Q5, Q6, Q7, Q8, Q9 MOSFET P-CHAN., 40V, FDD4685, DPAK OPT
20 1 Q10 XTOR N-CHAN., SOT23 DIODE INC., MMBTA42-7-F
21 1 Q11 XTOR N-CHAN., SOT23 DIODE INC., MMBT3904-7-F
22 1 R4 RES., CHIP 1.69M 0.125W 1% 0805 VISHAY, CRCW08051M69FKEA
23 3 R5, R8, R12 RES., CHIP 69.8k 0.125W 1% 0805 VISHAY, CRCW080569K8FKEA
24 3 R6, R9, R13 RES., CHIP 130k 0.125W 1% 0805 NIC, NRC10F1303TRF
25 1 R7 RES., CHIP 590k 0.125W 1% 0805 VISHAY, CRCW0805590KFKEA
26 1 R10 RES., CHIP 1.05M 0.125W 1% 0805 VISHAY, CRCW08051M05FKEA
27 1 R11 RES., CHIP 127k 0.1W 1% 0603 VISHAY, CRCW0603127KFKED
28 7 R14-R16, R20-R22, R29 RES., CHIP 1k 0.1W 5% 0603 VISHAY, CRCW06031K00JNEA
29 0 R17 RES., CHIP 845k 0.1W 1% 0603 OPT
30 0 R18 RES., CHIP 115k 0.06W 1% 0603 OPT
31 1 R19 RES., CHIP 30.9k 0.1W 1% 0603 VISHAY, CRCW060330K9FKEA
32 3 R23, R26, R28 RES., CHIP 249 0.1W 1% 0603 VISHAY, CRCW060249RFKEA
33 5 R30, R31, R32, R33, R36 RES., CHIP 100k 0.1W 5% 0603 NIC, NRC06J104TRF
34 1 R34 RES., CHIP 68k 0.25W 5% 1206 NIC, NRC12J683TRF
35 1 R35 RES., CHIP 240Ω 0.25W 1% 1206 VISHAY, CRCW1206240RFKEA
36 1 U1 I.C., POWERPATH CONTROLLER, QFN24UF-4×4 LINEAR TECH CORP. LTC4417CUF
37 3 U2,U3,U5 I.C., TRIPPLE 3-INPUT NOR GATE TSSOP14 NXP/PHILIPS SEMI. 74HC27PW
38 1 U4 I.C., LOW DROPOUT REG. TSOT23-8 LINEAR TECH CORP. LT3060ETS8-5
39 4 MH1-MH4 STANDOFF, NYLON, 0.50, 1/2" KEYSTONE, 8833 (SNAP ON)

8
dc1717afa
DEMO MANUAL DC1717A
schematic Diagram
5 5
4 4
3 3
2 2
1 1
D D C C B B A A
2. INSTALL SHUNTS ON JUMPERS AS SHOWN. 1. ALL RESISTORS ARE IN OHMS, 0603. ALL CAPACITORS ARE IN MICROFARADS, 0603. NOTES: UNLESS OTHERWISE SPECIFIED
LED DRIVER
V1 V2 V3
VOUT
V3
V2
V1
5V 5V 5V
5V5V
VS1 VS2 VS3
FG1
FG2 FG3
/VALID1 /VALID2 /VALID3 EN
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
VLAD O.PRODUCTION
__ 307-23-15
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
VLAD O.PRODUCTION
__ 307-23-15
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
VLAD O.PRODUCTION
__ 307-23-15
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
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.
SCALE = NONE
www.linear.com
3
DEMO CIRCUIT 1717A
Thursday, July 23, 2015 1 2
PRIORITIZED POWERPATH CONTROLLER
N/A LTC4417CUF
KIM T.
VLAD O.
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
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.
SCALE = NONE
www.linear.com
3
DEMO CIRCUIT 1717A
Thursday, July 23, 2015 1 2
PRIORITIZED POWERPATH CONTROLLER
N/A LTC4417CUF
KIM T.
VLAD O.
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
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.
SCALE = NONE
www.linear.com
3
DEMO CIRCUIT 1717A
Thursday, July 23, 2015 1 2
PRIORITIZED POWERPATH CONTROLLER
N/A LTC4417CUF
KIM T.
VLAD O.
Q1
Si7905DN
7 1
2
3 6 4
8 5
+
C2 OPT 2220
JP3
ON OFF
SHDN
1 3 2
D1
SMBJ26CA
E10 EN
G1
E11 SHDN
R4 1.69M 0805
Q11
MMBT3904
1
2 3
E12 CAS
D13 BAT42WS-V
12
R33 100k
C22 0.047uF 50V 0805
D14 BAT42WS-V
12
E6
R5 69.8K 0805
E2
FG1
JP2
ON OFF
EN
1 3 2
D15 BAT42WS-V
12
R26 249
R11 127k
R36 100k
R7 590K 0805
VS2
JP1
30mV RHYS
HYS
1 3 2
R10 1.05M 0805
E4
C11 1uF 50V
E3
D2
SMBJ26CA
VS1
C4 OPT 2220 C9 OPT 2220
R12 69.8K 0805
C6 OPT 2220
E7 VALID1
UV2
C17
0.1uF
50V
0805
J4 GND
C10 1uF 50V
R23 249
FG3
UV1
R34 68k 1206
J2
V2 (+5V)
J1
V1 (+12V)
C18
0.1uF
50V
0805
R30 100k
E16
D18
GRN VOUT
2 1
R28 249
VS3
C19
0.1uF
50V
0805
R8 69.8K 0805
D3
SMBJ26CA
UV3
U1
LTC4417
V1
21
UV1
1
OV1
2
UV2
3
V2
20
EP
25
OV2
4
V3
19
OV3
6
UV3
5
VS1
18
G1
17
VS2
16
G2
15
VS3
14
G3
13
VOUT
12
VALID1 7 VALID2 8 VALID3 9
EN 22
SHDN 23
HYS 24
CAS 11
GND
10
Q2
Si7905DN
7 1
2
3 6 4
8 5
J5
V3 (+8V)
J6
GND
+
C7 47uF 50V
SANYO
50CE47BS
FG2
OV2
R35 240 1206
C20 0.047uF 50V 0805
R6 130K 0805
Q10 MMBTA42
1
2 3
C3 OPT 1206 C8
OPT
1206 C1 OPT 1206
C12 1uF 50V
E8 VALID2
E1
G3
R13 130K 0805
G2
OV1
R32 100k
J3
VOUT
2A MAX
E9 VALID3
C5
OPT
1206
Q3
Si7905DN
7 1
2
3 6 4
8 5
R9 130K 0805
C21 0.047uF 50V 0805
R31 100k
OV3

9
dc1717afa
DEMO MANUAL DC1717A
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
OPTIONAL CIRCUIT
VOUT POWER SOURCE VALID STATUS
5V
5V
5V
V1 VOUT V2 VOUT
V3 VOUT
5V
/VALID3 /VALID1
EN
/VALID2
/VALID1 /VALID2 /VALID3
FG3
VS3 VS2
FG2
VS1 FG1
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
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.
SCALE = NONE
www.linear.com
3
DEMO CIRCUIT 1717A
Thursday, July 23, 2015 2 2
PRIORITIZED POWERPATH CONTROLLER
N/A LTC4417CUF
KIM T.
VLAD O.
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
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.
SCALE = NONE
www.linear.com
3
DEMO CIRCUIT 1717A
Thursday, July 23, 2015 2 2
PRIORITIZED POWERPATH CONTROLLER
N/A LTC4417CUF
KIM T.
VLAD O.
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
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.
SCALE = NONE
www.linear.com
3
DEMO CIRCUIT 1717A
Thursday, July 23, 2015 2 2
PRIORITIZED POWERPATH CONTROLLER
N/A LTC4417CUF
KIM T.
VLAD O.
3
1
2
GND VDD
U2 74HC27PW
1 2
13
3 4 5 9
10 11
7 14
12 6 8
R16 1k
R19 30.9K
D17
GRN
VALID1
21
R22 1k
D7
MMSZ5231BT1G
5.1V
OPT
12
D12 GRN LDO
2 1
R18 115k OPT
D16
GRN
VALID3
21
E13 5V
GND VDD
U3 74HC27PW
1 2
13
3 4 5 9
10 11
7 14
12 6 8
D8
GRN
V1
21
R21 1k
Q7 FDD4685
3
1
2
3
1
2
C14 10uF 10V 0805
E14
AUXILIARY VOLTAGE INPUT
6V - 24V
Q9 FDD4685
3
1
2
R14 1k
U4 LT3060ETS8-5
GND
4
ADJ 7
REF/BYP
8
SHDN
1
OUT 6
IN
5
GND
2
GND
3
Q6 FDD4685
3
1
2
GND VDD
U5 74HC27PW
1 2
13
3 4 5 9
10 11
7 14
12 6 8
3
1
2
C16 10nF 50V 0805
3
1
2
3
1
2
Q5 FDD4685
3
1
2
R29
1k
C15 1uF 50V
E15
GND
R15 1k
Q4 FDD4685
3
1
2
C13 1uF 50V
R20 1k
R17 845k OPT
D9
GRN
V2
21
3
1
2
D10
GRN
V3
21
D11
GRN
VALID2
21
Q8 FDD4685
3
1
2

10
dc1717afa
DEMO MANUAL DC1717A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2013
LT 0915 REV A • 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 LTC 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 LTC 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. LTC assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LTC 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 LTC applica-
tion engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation

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