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DESCRIPTION
Demonstration circuits 826C-A and 826C-B feature the
LTC
2950-2
and the
LTC2951-2
®
low power, wide input voltage range, pushbutton on/off
controllers. A pushbutton switch shorts the PB pin to
ground which in turn sets the EN pin low (see Note 1).
Shorting PB to ground a second time subsequently resets
the EN pin high. The EN pin is used to connect to a DC/
DC converter shutdown to control the turn on and off of
the circuit, simulated with a green LED on the DC826C-A/
DC826C-B.
JP1 and JP2 on the DC826C-A provide the selection
of timing options for the PB on and off times. For the
DC826C-B, JP1 selects KILL times while JP2 selects off
IC SELECTION GUIDE
Table 1. LTC2950/LTC2951 Selection Guide (Typical Timing Values, Cap. Adjust = 212ms on DC826C-A/DC826C-B)
PART
ENABLE ONT
LTC2950-1
EN
32ms + Cap. Adjust*
LTC2950-2
EN
32ms + Cap. Adjust*
LTC2951-1
EN
128ms
LTC2951-2
EN
128ms
*The additional Cap. Adjust time is selected by an external capacitor. The DC826C-A and DC826C-B adjust times have been pre-selected with a 0.033μF
capacitor to provide an additional 212ms. The additional time is calculated with the following equations as shown in the LTC2950/LTC2951 data sheets:
C
= 1.56e-4 [μF/ms] • (t
ONT
ONT
C
= 1.56e-4 [μF/ms] • (t
OFFT
C
= 1.56e-4 [μF/ms] • (t
KILLT
respectively, which are
OFFT
32ms + Cap. Adjust*
32ms + Cap. Adjust*
32ms + Cap. Adjust*
32ms + Cap. Adjust*
– 1ms)
– 1ms)
OFFT
,
– 1ms)
KILL
OFF DELAY, ADDITIONAL
DC826C-A/DC826C-B
LTC2950-2/LTC2951-2
Pushbutton On/Off Controller
times. JP3 ties and unties KILL to INT for immediate or
delayed turn off. The INT status is shown with a red LED.
DC826C-A/DC826C-B accepts an input voltage range of
2.7V to 26.4V or a 9V battery for portable demonstration
and evaluation.
Note 1: The inversion of EN of the LTC2950-2/LTC2951-2
is found in the LTC2950-1/LTC2951-1. Table 1 provides
an IC selection guide.
Design files for this circuit board are available at
http://www.linear.com/demo/DC826C
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.
KILLT
1000ms
1000ms
128ms + Cap. Adjust*
128ms + Cap. Adjust*
DEMO MANUAL
DEMO BOARD
N/A
DC826C-A
N/A
DC826C-B
dc826cf
1
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Related Manuals for Linear Technology DC826C-A
Summary of Contents for Linear Technology DC826C-A
- Page 1 DC826C-B *The additional Cap. Adjust time is selected by an external capacitor. The DC826C-A and DC826C-B adjust times have been pre-selected with a 0.033μF capacitor to provide an additional 212ms. The additional time is calculated with the following equations as shown in the LTC2950/LTC2951 data sheets: = 1.56e-4 [μF/ms] •...
-
Page 2: Quick Start Procedure
(LTC2950-2) by two external capacitors C1 and power is connected in an application such that the polari- C2 and selected on the DC826C-A with jumper JP1 and ties are ensured to be in the correct configuration, this RC JP2. The status of the EN pin, and simulation of the turn may be removed from the circuit. - Page 3 DEMO MANUAL DC826C-A/DC826C-B OPERATING PRINCIPLES PUSHBUTTON DC/DC BUCK 2.7V TO 26.4 SHDN 9V BATTERY µP/µC KILL DC826C F01 Figure 1. DC826C-A/DC826C-B Example Setup dc826cf...
-
Page 4: Schematic Diagram
DEMO MANUAL DC826C-A/DC826C-B SCHEMATIC DIAGRAM dc826cf... - Page 5 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.
- Page 6 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.
- Page 7 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Analog Devices Inc. DC826C-A DC826C-B...
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