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参数资料
| 型号： | LTC2951IDDB-1#TRMPBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 电源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8 |
| 封装： | 3 X 2 MM, LEAD FREE, PLASTIC, MO-229WEED-1, DFN-8 |
| 文件页数： | 16/16页 |
| 文件大小： | 213K |
| 代理商： | LTC2951IDDB-1#TRMPBF |
LTC2951-1/LTC2951-2
9
295112fa
Description
The LTC2951 is a low power (6A), wide input voltage range
(2.7V to 26.4V), push button On/Off controller that can
interface to a P and a power supply. The part incorporates
all the exible timing needed to debounce the push button
input (PB). The LTC2951 also provides a simple interface
(INT output, KILL input) to allow a system to power on and
power off in a controlled manner. The wide input voltage
range allows a system designer to operate from single cell
to multi-cell battery stacks. Very low quiescent current
makes the LTC2951 ideal for continuously monitoring the
On/Off push button of a handheld device.
Turn On
When power is rst applied to the LTC2951, the part initial-
izes the output pins. Any DC/DC converters connected to
the EN/EN pin will therefore be off. To assert the enable
output, PB must be held low for a minimum of 128ms
(tDB, ON).
Once the enable output is asserted, any DC/DC converters
connected to this pin are turned on. The KILL input from
the P is ignored during the succeeding 512ms blanking
time (t KILL, ON BLANK). This blanking time represents the
maximum time required to power up the DC/DC converter
and the P. If KILL is not brought high during this 512ms
time window, the enable output is released. The assump-
tion is that 512ms is sufcient time for the system to
power up.
Turn Off
To initiate a power off sequence, PB must be held low for a
minimum of 32ms (tDB, OFF). Additional turn off debounce
time may be added via an optional capacitor connected to
the OFFT pin (tOFFT). The following equation describes the
additional time that PB must be held low to initiate a power
off sequence. COFFT is the OFFT external capacitor:
COFFT = 1.56E-4 [μF/ms] (tOFFT – 1ms)
Once PB has been validly pressed, INT is switched low.
This alerts the P to perform its power down and house-
keeping tasks.
KILL Turn Off Delay
The LTC2951 provides a failsafe feature that allows the
user to turn off system power (via PB) under system fault
conditions. During a normal power down sequence, the
LTC2951 rst interrupts the P by setting INT low. The
P then performs power down and housekeeping tasks
and drives KILL low when done. The LTC2951 releases the
enable output, thus turning off system power. The KILL
turn off timer starts when INT is driven low. If the P fails
to respond during this timeout period, the enable output
will automatically release. The default power down timeout
period is 128ms (tKILL, OFF DELAY), which can be extended
by placing an optional capacitor on the KILLT pin (tKILL,
OFF DELAY, ADDITIONAL). The following equation describes
the additional power down timeout period. CKILLT is the
KILLT external capacitor:
CKILLT = 1.56e-4 [F/ms] (tKILL, OFF DELAY, ADDITIONAL – 1ms)
Note that KILL can be driven low (thereby releasing the
enable output) at any time after tKILL, ON BLANK period.
Simplied Power On/Off Sequence
Figure 1 shows a simplied LTC2951-1 power on and power
off sequence. A high to low transition on PB (t1) initiates
the power on sequence. This diagram does not show any
bounce on PB. In order to assert the enable output, the PB
pin must stay low continuously (PB high resets timers) for
128ms (t2–t1). Once EN goes high (t2), an internal 512ms
blanking timer is started. This blanking timer is designed
to give sufcient time for the DC/DC converter to reach its
nal voltage, and to allow the P enough time to perform
power on tasks.
The KILL pin must be pulled high within 512ms of the
EN pin going high. Failure to do so results in the EN
pin going low 512ms after it went high. (EN = low, see
Figure 2). Note that the LTC2951 does not sample KILL
and PB until after the 512ms internal timer has expired.
The reason PB is ignored is to ensure that the system
is not forced off while powering on. Once the 512ms
timer expires (t4), the release of the PB pin is then
debounced with an internal 32ms timer. The system has
now properly powered on and the LTC2951 monitors PB
APPLICATIO S I FOR ATIO
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相关代理商/技术参数 |
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| LTC2951IDDB-2#TRMPBF | 功能描述:IC PUSH BUTTON ON/OFF CTRLR 8DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电源控制器，监视器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 应用:多相控制器 输入电压:- 电源电压:9 V ~ 14 V 电流 - 电源:- 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:40-WFQFN 裸露焊盘 供应商设备封装:40-TQFN-EP（5x5） 包装:带卷 (TR) |
| LTC2951IDDB-2#TRPBF | 功能描述:IC PUSH BUTTON ON/OFF CTRLR 8DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电源控制器，监视器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 应用:多相控制器 输入电压:- 电源电压:9 V ~ 14 V 电流 - 电源:- 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:40-WFQFN 裸露焊盘 供应商设备封装:40-TQFN-EP（5x5） 包装:带卷 (TR) |
| LTC2951ITS8-1 | 制造商:Linear Technology 功能描述:Push Button Controller 8-Pin TSOT-23 |
| LTC2951ITS8-1#PBF | 制造商:Linear Technology 功能描述:MS-System Monitor/Other, Cut Tape Basic Push Button On/Off Controller (Adjustabl |
| LTC2951ITS8-1#TRM | 制造商:Linear Technology 功能描述:Push Button Controller 8-Pin TSOT-23 T/R |
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