1
dc2254af
DEMO MANUAL DC2254A
Description
LTC2956
Wake-Up Timer
with Pushbutton Control
Demonstration circuits 2254A-A and 2254A-B feature the
LTC2956-1 and LTC2956-2, respectively. The LT C
®
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.
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
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
Figure 1. Test Equipment Setup
PSU
I/O TO
SCOPE OR
µP
+
–
2
dc2254af
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 pres-
ent 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 Infor-
mation 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.
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 tur-
ret 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 pushbut-
ton 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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dc2254af
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.
RUN AND SHUTDOWN MODE
The LTC2956 has two modes of operation: RUN mode
and SHUTDOWN mode.
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.
The SHUTDOWN mode is a very low power mode with the
timer disabled, entered through a press of the pushbut-
ton 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.
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
3 SHUTDOWN 1.024s
4 SHUTDOWN 2.048s
5 RUN 0.128s
6 RUN 0.512s
7 RUN 1.024s
8 RUN 2.048s
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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dc2254af
DEMO MANUAL DC2254A
operatinG principLes
Figure 2. LTC2956-1, Awake Time Set to 20ms, Time Period Set to 250ms
PBOUT
EN
20ms AWAKE TIME
250ms TIME PERIOD
5
dc2254af
DEMO MANUAL DC2254A
operatinG principLes
Figure 3. LTC2956-1, Awake Time Set to 20ms, Time Period Set to 250ms, Showing Proper Turn On Sequence with ONALERT Signal
PBOUT
ONALERT
EN
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dc2254af
DEMO MANUAL DC2254A
operatinG principLes
Figure 4. LTC2956-1, Awake Time Set to 20ms, Time Period Set to 250ms, Showing Proper Shutdown Sequence with OFFALERT Signal
PBOUT
ONALERT
EN
1 SEC OFFALERT
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dc2254af
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)
8
dc2254af
DEMO MANUAL DC2254A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
DC2254A-A Required Circuit Components
1 1 DC2254A1-GENERAL BOM
2 1 Q1 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 DC2254A1-GENERAL BOM
2 0 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
9
dc2254af
DEMO MANUAL DC2254A
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
DD
C C
BB
A A
NOTE: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTORS ARE IN OHMS, 0402. ALL CAPACITORS ARE IN MICROFARADS, 0603.
0.128s SHUT DOWN
0.512s SHUT DOWN
1.024s SHUT DOWN
2.048s SHUT DOWN
0.512s RUN
0.128s RUN
1.024s RUN
2.048s RUN
E7, LED1
EN
ASSY U1
*A LTC2956 - 1
*
B
SUFFIX
1
Q1 R17 R18
EN2LTC2956 - 2
2N7002
OPT
430
OPT
OPT
430
ON1
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
SAL H.
PRODUCTION 41-11-801
__
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
SAL H.
PRODUCTION 41-11-801
__
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
SAL H.
PRODUCTION 41-11-801
__
SIZE
DATE:
.VER.ON CI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 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
1
Monday, August 11, 2014
1 1
WAKE UP TIMER WITH PUSH BUTTON CONTROL
KIM T.
SAL H.
N/A
LTC2956IUD-1 / 2
DEMO CIRCUIT 2254A
SIZE
DATE:
.VER.ON CI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 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
1
Monday, August 11, 2014
1 1
WAKE UP TIMER WITH PUSH BUTTON CONTROL
KIM T.
SAL H.
N/A
LTC2956IUD-1 / 2
DEMO CIRCUIT 2254A
SIZE
DATE:
.VER.ON CI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 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
1
Monday, August 11, 2014
1 1
WAKE UP TIMER WITH PUSH BUTTON CONTROL
KIM T.
SAL H.
N/A
LTC2956IUD-1 / 2
DEMO CIRCUIT 2254A
JP2
RANGE TIME PERIOD
250ms
1s
JP2
RANGE TIME PERIOD
250ms
1s
1
3
2
LED4
YELLOW
PBOUT
LED4
YELLOW
PBOUT
21
E1
ONMAX
E1
ONMAX
E5
1.6V - 36V
VIN E5
1.6V - 36V
VIN
R9
100k
R9
100k
R16
OPT
R16
OPT
R26
470
R26
470
R11
17.4k
R11
17.4k
R18
*
R18
*
U2
LT3060ETS8
U2
LT3060ETS8
GND
2
GND
3
GND
4
IN
5OUT 6
REF/BYP 8
SHDN
1ADJ 7
E4
OFFALERT
E4
OFFALERT
R22
430
R22
430
E13
GND
E13
GND
R12
9.76k
R12
9.76k
LED3
RED
OFFALERT
LED3
RED
OFFALERT
21
R15
1k
R15
1k
C2
0.1uF
C2
0.1uF
R27
49.9k
R27
49.9k
E6
PBOUT
E6
PBOUT
R7 280kR7 280k
R20
430
R20
430
R5 127kR5 127k
E3
SLEEP
E3
SLEEP
C4
2.2uF
C4
2.2uF
E11
GND
E11
GND
C5
1uF
C5
1uF
R1 9.76kR1 9.76k
LED2
YELLOW
ONALERT
LED2
YELLOW
ONALERT
21
U1
LTC2956 -
U1
LTC2956 -
PB
8
LONG 3
PERIOD
5
VIN
6
RANGE
4
EN/EN
9
GND
7
ONMAX 2
SLEEP 12
ONALERT1
PBOUT 10
OFFALERT 11
EP
13
SW2
EVQPE105K
PB
SW2
EVQPE105K
PB
12
R2 26.1kR2 26.1k
JP1
AWAKE TIMER
13.3ms/nF
19.9ms
EXTERNAL
JP1
AWAKE TIMER
13.3ms/nF
19.9ms
EXTERNAL
1
3
2
R3 35.7kR3 35.7k
R23
100k
R23
100k
C6
0.01uF
C6
0.01uF
R10
100k
R10
100k
R17
*
R17
*
E12
PB
E12
PB
C3
OPT
C3
OPT
Q1
*
Q1
*
2
1
3
R14 1kR14 1k
LED5
GREEN
LED SUPPLY
LED5
GREEN
LED SUPPLY
2 1
R13 100kR13 100k
E10
5V - 36V
LDO_IN E10
5V - 36V
LDO_IN
R21
100k
R21
100k
E8
2.5V, 100mA
LDO_OUT
E8
2.5V, 100mA
LDO_OUT
R25
158k
R25
158k
R8 383kR8 383k
E7
*
E7
*
JP3
LDO_IN
EXT
INT
JP3
LDO_IN
EXT
INT
1
3
2
LED1
GREEN
*
LED1
GREEN
*
21
R6 210kR6 210k
SW1
BD08
SW1
BD08
1
2
3
4
5
6
7
8 9
10
11
12
13
14
15
16
E9
GND
E9
GND
E2
ONALERT
E2
ONALERT
R19
100k
R19
100k
R4 47.5kR4 47.5k
C1
1500pF
C1
1500pF
R24
430
R24
430
10
dc2254af
DEMO MANUAL DC2254A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
LINEAR TECHNOLOGY CORPORATION 2014
LT 0914 • 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:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
