DC2254A - Demo Manual

DEMO MANUAL DC2254A
LTC2956
Wake-Up Timer
with Pushbutton Control
Description
Demonstration circuits 2254A-A and 2254A-B feature the
LTC2956-1 and LTC2956-2, respectively. The LTC®2956
is a micropower, wide input voltage range, configurable
wake-up timer with pushbutton control. It periodically
wakes up and turns on a connected system to perform
tasks like monitoring temperature or capturing images.
After completing the task, the LTC2956 turns the system
off to conserve power. The wake-up timer period can be
adjusted from 250ms to 39 days.
The DC2254A allows easy access to all the pins necessary
to configure the device. Onboard jumpers, and an 8-pin
DIP switch provide a range of value options, to set the
wake-up timer, wake-up timer period and long power down
time. Turrets are also present, allowing direct access to all
the pins present on the LTC2956 to allow easy interfacing
with a system with arbitrary requirements.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2254A
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Board Photo
+
PSU
–
I/O TO
SCOPE OR
µP
Figure 1. Test Equipment Setup
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DEMO MANUAL DC2254A
DC2254A TURRET AND JUMPER DEFINITIONS
JUMPER AND SWITCH SETTINGS
RANGE TIME PERIOD (JP2): Sets the time period between
enable signal assertions. The two available options present on the board are 250ms and 1s. See Applications
Information in the LTC2956 data sheet and replace R11
and/or R12 if another time is desired.
AWAKE TIMER (JP1): Sets the time the enable signal stays
asserted. The onboard capacitor can be used for an awake
time of 19.9ms or an external arbitrary capacitor can be
used to set a user defined enable time. The maximum
allowed awake time is set at 13.3ms/nF.
LDO_IN (JP3): Choose the input to the onboard LT3060
regulator. It can either be set to INT to have it connected
to the VIN pin, or EXT in order to have it driven by the
LDO_IN turret. See the Operating Principles section. Only
for LED/Monitor circuitry.
SW1: This 8 pin DIP switch can be used to initialize the
part in either RUN or SHUTDOWN mode and also allows
configuration of the tLONG time. See Applications Information in the LTC2956 data sheet for more information.
SW2: This pushbutton switch controls the input to the PB
pin. This is an active low input with a 900kΩ pull up to an
internal 3.3V regulated supply. When the pushbutton is
pressed, EN/EN pin gets asserted after an initial debounce
time of 32ms.
EXTERNAL CONNECTIONS
Signal connections are made via the row of turret posts
along the edges of the board.
GND: (3 Turrets) These turrets are connected directly to
the ground planes.
VIN: Connect a 1.6V to 36V power supply to this turret.
ONMAX: Connect a capacitor from this turret to GND if
an arbitrary awake time is desired. Use the relationship
tAWAKETIME = 13.3ms/nF. Set the AWAKE TIMER jumper
to EXTERNAL if using this turret.
2
PB: This turret is already driven by the pushbutton present
on the demoboard, however if needed it can be driven by
an external signal to simulate a pushbutton press.
LDO_IN: Can be used to provide the LT3060 with power
when the LDO_IN jumper is set to EXT.
LDO_OUT: Output from the LT3060. The state of this turret can be monitored by the LED labelled “LED SUPPLY”.
DIGITAL CONNECTIONS
EN/EN: Active high (LTC2956-1) or active low (LTC2956-2)
signal. Should go active either with a debounced pushbutton press or after a valid time period set by the RANGE
TIME PERIOD jumper.
ONALERT: This turret pulls low whenever the part goes
from SHUTDOWN mode to RUN mode. The signal stays
low while the EN/EN pin is asserted and it can be used as
an input to a system to request for initial boot up routine.
This turret may be left open if unused.
OFFALERT: This turret pulls low for 1 second whenever
the part goes from RUN mode to SHUTDOWN mode.
This pin can be connected to the interrupt input (with a
pullup resistor to the system supply) of a system to alert
the system before shutdown. This pin may be left open
if unused.
SLEEP: This turret is an input and is active during RUN
mode. In the Awake state, a falling edge at the SLEEP input
will de-assert EN/EN and put the system into the Sleep state.
If the SLEEP input goes high during the Sleep state, the
LTC2956 reenters the Awake state and re-asserts EN/EN
to turn a system on. Holding this turret high for more
than tLONG (which is set by SW1) will force the LTC2956
into SHUTDOWN mode. See data sheet for more details.
PBOUT: This turret follows the debounced PB input. This
turret may be left open if unused.
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DEMO MANUAL DC2254A
OPERATING PRINCIPLES
Connect a 1.6V to 36V power supply to VIN. If VIN is
less than 5.5V then set the LDO_IN jumper to EXTERNAL
and connect a 5.5V to 35V supply to the LDO_IN turret.
The LTC2956 will still operate with no power applied to
LDO_IN, but monitor LEDs will not function.
On power up, the LTC2956 can be initialized to either of
these two modes. SW1 provides 8 different options to
initialize the part as shown in Table 1.
Table 1. SW1 Configuration Table
SW1 POSITION
MODE
TLONG
1
SHUTDOWN
0.128s
2
SHUTDOWN
0.512s
The LTC2956 has two modes of operation: RUN mode
and SHUTDOWN mode.
3
SHUTDOWN
1.024s
4
SHUTDOWN
2.048s
In RUN mode, the LTC2956 cycles between the Awake
state and the Sleep state with a period of tPERIOD which
is set by the RANGE TIME PERIOD jumper. During the
Awake state, the EN/EN pin is asserted to turn the system
on, and the tONMAX timer runs. The tONMAX timer can be
configured with the AWAKE TIMER jumper. The LTC2956
exits the Awake state when a falling edge is detected on
the SLEEP pin or if the tONMAX timer expires. In the Sleep
state the EN/EN output stays de-asserted. The LTC2956
only returns to the Awake state when the tPERIOD time
is reached, pushbutton is pressed or if a logic high is
detected on the SLEEP pin. The LTC2956 can be put into
SHUTDOWN mode if the pushbutton is held low for longer
than a user defined tLONG period.
5
RUN
0.128s
6
RUN
0.512s
7
RUN
1.024s
8
RUN
2.048s
RUN AND SHUTDOWN MODE
The SHUTDOWN mode is a very low power mode with the
timer disabled, entered through a press of the pushbutton or a high pulse at the SLEEP input which lasts longer
than tLONG. A short press on the pushbutton brings the
LTC2956 back into RUN mode.
ONALERT AND OFFALERT SIGNALS
The ONALERT signal pulls low when the LTC2956 enters
RUN mode from SHUTDOWN. This signal is useful to allow
connected systems to run initialization tasks.
The OFFALERT signal pulls low when the LTC2956 enters
SHUTDOWN mode from RUN mode. When the PB pin is
held low for a time longer than tLONG during RUN mode, the
LTC2956 first pulls the OFFALERT pin low which lasts for
tOFF (1s typ). Once the tOFF timer completes, the LTC2956
transitions to the SHUTDOWN mode.
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DEMO MANUAL DC2254A
OPERATING PRINCIPLES
PBOUT
250ms TIME PERIOD
EN
20ms AWAKE TIME
Figure 2. LTC2956-1, Awake Time Set to 20ms, Time Period Set to 250ms
4
dc2254af
DEMO MANUAL DC2254A
OPERATING PRINCIPLES
PBOUT
EN
ONALERT
Figure 3. LTC2956-1, Awake Time Set to 20ms, Time Period Set to 250ms, Showing Proper Turn On Sequence with ONALERT Signal
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DEMO MANUAL DC2254A
OPERATING PRINCIPLES
PBOUT
EN
1 SEC OFFALERT
ONALERT
Figure 4. LTC2956-1, Awake Time Set to 20ms, Time Period Set to 250ms, Showing Proper Shutdown Sequence with OFFALERT Signal
6
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DEMO MANUAL DC2254A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
1
C1
CAP., X7R, 1500pF, 25V, 10%, 0603
AVX, 06033C152KAT2A
2
1
C2
CAP., X7R, 0.1µF, 50V, 5%, 0603
AVX, 06035C104JAT2A
3
0
C3
CAP., 0603
OPT
4
1
C4
CAP., X7R, 2.2µF, 10V, 20%, 0603
MURATA, GRM188R71A225ME15D
5
1
C5
CAP., X5R, 1µF, 50V, 10%, 0603
NIC, NMC0603X5R105K50TRPF
6
1
C6
Cap., X7R, 0.01µF, 10V, 10%, 0603
AVX, 0603ZC103KAT2A
7
13
E1-E13
TP, TURRET, 0.064", PAD120-064
MILL-MAX, 2308-2-00-80-00-00-07-0
8
3
JP1, JP2, JP3
HD1X3-079
SAMTEC, TMM103-02-L-S
9
2
LED1, LED5
LED, GREEN
ROHM, SML-010FTT86L
10
2
LED2-LED4
LED, YELLOW
ROHM, SML-010YTT86M
11
1
LED3
LED, RED
ROHM, SML-010VTT86L
12
2
R1, R12
Res., Chip 9.76k, 1/16W, 1%, 0402
VISHAY, CRCW04029K76FKED
13
1
R2
Res., Chip 26.1k, 1/16W, 1%, 0402
VISHAY, CRCW040226K1FKED
14
1
R3
Res., Chip 35.7k, 1/16W, 1%, 0402
VISHAY, CRCW040235K7FKED
15
1
R4
Res., Chip 47.5k, 1/16W, 1%, 0402
VISHAY, CRCW040247K5FKED
16
1
R5
Res., Chip 127k, 1/16W, 1%, 0402
VISHAY, CRCW0402127KFKED
17
1
R6
Res., Chip 210k, 1/16W, 1%, 0402
VISHAY, CRCW0402210KFKED
18
1
R7
Res., Chip 280k, 1/16W, 1%, 0402
VISHAY, CRCW0402280KFKED
19
1
R8
Res., Chip 383k, 1/16W, 1%, 0402
VISHAY, CRCW0402383KFKED
20
6
R9, R10, R13, R19, R21, R23
Res., Chip 100k, 1/16W, 1%, 0402
VISHAY, CRCW0402100KFKED
21
1
R11
Res., Chip 17.4k, 1/16W, 1%, 0402
VISHAY, CRCW040217K4FKED
22
2
R14, R15
Res., Chip 1k, 1/16W, 1%, 0402
VISHAY, CRCW04021K00FKED
23
0
R16
Res, 0402
OPT
24
3
R20, R22, R24
Res., Chip 430, 1/16W, 5%, 0402
VISHAY, CRCW0402430RJNED
25
1
R25
Res., Chip 158k, 1/16W, 1%, 0402
VISHAY, CRCW0402158KFKED
26
1
R26
Res., Chip 470, 1/16W, 5%, 0402
VISHAY, CRCW0402470RJNED
27
1
R27
Res., Chip 49.9k, 1/16W, 1%, 0402
VISHAY, CRCW040249K9FKED
28
1
SW1
SWITCH, 8 Position DIP
C&K Components, BD08
29
1
SW2
SWITCH, Pushbutton
PANASONIC, EVQPE105K
30
1
U2
I.C., LT3060ETS8, TS8
LINEAR TECH., LT3060ETS8
31
4
MH1-MH4
STAND-OFF, NYLON 0.25" TALL
KEYSTONE, 8831(SNAP ON)
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DEMO MANUAL DC2254A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
DC2254A-A Required Circuit Components
1
1
2
1
Q1
DC2254A1-GENERAL BOM
MOSFET, N-CH, SOT23
FAIRCHILD SEMI., 2N7002
3
0
R17
RES., 0402
OPT
4
1
R18
RES., CHIP, 430, 1/16W 5%, 0402
VISHAY, CRCW0402430RJNED
4
1
U1
I.C., QFN12UD-3X3
LINEAR TECH., LTC2956IUD-1
DC2254A-B Required Circuit Components
1
1
2
0
DC2254A1-GENERAL BOM
Q1
MOSFET, N-CH, SOT23
OPT
3
1
R17
RES., CHIP, 430, 1/16W, 5%, 0402
VISHAY, CRCW0402430RJNED
4
0
R18
RES., 0402
OPT
4
1
U1
I.C., QFN12UD-3X3
LINEAR TECH., LTC2956IUD-2
8
dc2254af
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
A
B
C
D
*
E11
E10
E12
E13
E5
127k
210k
280k
383k
R5
R6
R7
R8
JP3
LDO_IN
1
INT
2
3
EXT
47.5k
R4
C5
1uF
5
ADJ
SHDN
LT3060ETS8
REF/BYP
OUT
IN
2
3 GND
4 GND
GND
1
U2
JP2
RANGE TIME PERIOD
1
1s
2
3
250ms
0.128s SHUT DOWN
0.512s SHUT DOWN
1.024s SHUT DOWN
2.048s SHUT DOWN
0.128s RUN
0.512s RUN
1.024s RUN
2.048s RUN
1
2
3
4
5
6
7
8
ON
8
7
6
R12
9.76k
R11
17.4k
BD08
SW1
1
C6
0.01uF
16
15
14
13
12
11
10
9
C3
OPT
C2
0.1uF
R14 1k
R13 100k
R9
100k
LTC2956 - 2
A
B
5
U1
LTC2956 - 1
ASSY
2
1
SUFFIX
EN
EN
E7, LED1
4
OPT
430
R17
OPT
Q1
2N7002
OPT
430
R18
3
PB
R15
1k
2
C4
2.2uF
*
R17
1
10
11
12
*
*
*
LED1
L
ED1
GREEN
*
R18
Q1
U1
LTC2956 -
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
CUSTOMER NOTICE
LED SUPPLY
LED5
GREEN
R26
470
R16
OPT
PBOUT
OFFALERT
SLEEP
R10
100k
2
SCALE = NONE
SAL H.
KIM T.
R21
100k
__
ECO
1
OFFALERT
LED3
RED
R22
430
E9
E8
E7
E6
E4
E3
GND
LDO_OUT
2.5V, 100mA
*
PBOUT
OFFALERT
SLEEP
ONALERT
SAL H.
E2
DATE
0 8 - 1 1 -1 4
APPROVED
PBOUT
LED4
YELLOW
R24
430
1
DATE:
N/A
SIZE
1
LTC2956IUD-1 / 2
DEMO CIRCUIT 2254A
Monday, August 11, 2014
IC NO.
SHEET 1
1
OF 1
REV.
WAKE UP TIMER WITH PUSH BUTTON CONTROL
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
R23
100k
PRODUCTION
DESCRIPTION
REVISION HISTORY
TECHNOLOGY
REV
TITLE: SCHEMATIC
ONALERT
LED2
YELLOW
R20
430
2
APPROVALS
R19
100k
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APP ENG.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
SW2
EVQPE105K
1
VIN
PERIOD
RANGE
R27
49.9k
R25
158k
6
5
4
AWAKE TIMER
EXTERNAL
3
2
13.3ms/nF
1
19.9ms
C1
JP1
1500pF
1. ALL RESISTORS ARE IN OHMS, 0402. ALL CAPACITORS ARE IN MICROFARADS, 0603.
NOTE: UNLESS OTHERWISE SPECIFIED
GND
LDO_IN
5V - 36V
PB
GND
VIN
1.6V - 36V
26.1k
35.7k
R3
9.76k
R2
R1
EP
13
LONG
E1
8
GND
2
ONMAX
PB
1
ONALERT
EN/EN
9
ONMAX
2
3
2
1
3
2
1
4
2
1
7
1
2
2
1
5
A
B
C
D
DEMO MANUAL DC2254A
Schematic Diagram
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9
DEMO MANUAL DC2254A
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LTC) 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 application engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
10 Linear Technology Corporation
dc2254af
LT 0914 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014
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