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參數(shù)資料
| 型號： | LTC2927CDDB#TRM |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 電源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8 |
| 封裝： | 3 X 2 MM, PLASTIC, MO-229WECD-1, DFN-8 |
| 文件頁數(shù)： | 14/16頁 |
| 文件大小： | 264K |
| 代理商： | LTC2927CDDB#TRM |
LTC2927
7
2927fb
0.8V
–
+
–
+
5
RAMPBUF
5
RAMP
2927 F06
5
VCC
5
FB
5
ON
5
TRACK
1.2V
10μA
VCC
1x
RONB
RONA
MASTER
SLAVE
DC/DC
CRAMP
RTB
RFB
RFA
RTA
Figure 6. Simplied Functional Diagram
Figure 5. Simplied Tracking Cell
0.8V
–
+
2927 F05
5
FB
5
TRACK
VCC
MASTER
SLAVE
FB OUT
DC/DC
RTB
RFB
RFA
RTA
+
–
pin is mirrored at the FB pin to establish a voltage at the
output of the slave supply. The slave output voltage varies
with the master signal, enabling the slave supply to be
controlled as a function of the master signal with terms
set by RTA and RTB. By selecting appropriate values of
RTA and RTB, it is possible to generate any of the proles
in Figures 1 to 4.
Controlling the Ramp-Up and Ramp-Down Behavior
The operation of the LTC2927 is most easily understood
by referring to the simplied functional diagram in Figure
6. When the ON pin is low, the master signal at the RAMP
pin is pulled to ground. Since the current through RTB is
at its maximum when the master signal is low, the current
from FB is also at its maximum. This current drives the
slave output to its minimum voltage.
When the ON pin rises above 1.23V, the master signal
rises and the slave supply tracks the master signal. The
ramp rate is set by an external capacitor driven by a 10μA
current source at the RAMP pin. Alternatively, the RAMP
pin can be connected to a separate supply to be used as
the master signal.
In a properly designed system, when the master signal
has reached its maximum voltage the current from the
TRACK pin is zero. In this case, there is no current from
the FB pin and the LTC2927 has no effect on the output
voltage accuracy, transient response or stability of the
slave supply.
When the ON pin falls below VON(TH) – ΔVON(HYST), typi-
cally 1.225V, the RAMP pin pulls down with 10μA and the
master signal and slave supplies will fall at the same rate
as they rose previously.
The ON pin can be controlled by a digital I/O pin or it
can be used to monitor an input supply. By connecting a
resistive divider from an input supply to the ON pin, the
supplies will ramp up only after the monitored supply has
reached a preset voltage.
If a resistive divider is used to set the ON pin voltage, choose
values that will keep this voltage above the maximum ON
pin threshold voltage of 1.25V at the lowest operating
supply level.
The Ramp Buffer
The RAMPBUF pin provides a buffered version of the
RAMP pin voltage that drives the resistive divider on the
TRACK pin. The buffered master signal provides up to
2mA to drive the resistors.
Shutdown Output
In some applications it might be necessary to control
the shutdown or RUN/SS pins of the slave supplies. The
LTC2927 may not be able to supply the rated 1mA of current
from the FB pin when VCC is below 2.9V. If the slave power
supply is capable of operating at low input voltages, use
the open-drain SDO output to drive the SHDN or RUN/SS
pin of the slave supply (see Figure 7). This will hold the
slave supply output low until the ON pin is above 1.23V
and VCC is above the 2.5V undervoltage lockout condition.
APPLICATIO S I FOR ATIO
WU
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LTC2927CTS8#PBF | 制造商:Linear Technology 功能描述:Power Supply 8-Pin TSOT-23 制造商:Linear Technology 功能描述:MS-System Monitor/Other, Cut Tape Single Power Supply Tracking Controller |
| LTC2927CTS8#TR | 功能描述:IC POWER SUPPLY CTRLR TSOT23-8 RoHS:否 類別:集成電路 (IC) >> PMIC - 電源控制器，監(jiān)視器 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 應用:多相控制器 輸入電壓:- 電源電壓:9 V ~ 14 V 電流 - 電源:- 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:40-WFQFN 裸露焊盤 供應商設備封裝:40-TQFN-EP（5x5） 包裝:帶卷 (TR) |
| LTC2927CTS8#TRM | 功能描述:IC POWER SUPPLY CTRLR TSOT23-8 RoHS:否 類別:集成電路 (IC) >> PMIC - 電源控制器，監(jiān)視器 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 應用:多相控制器 輸入電壓:- 電源電壓:9 V ~ 14 V 電流 - 電源:- 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:40-WFQFN 裸露焊盤 供應商設備封裝:40-TQFN-EP（5x5） 包裝:帶卷 (TR) |
| LTC2927CTS8#TRMPBF | 功能描述:IC POWER SUPPLY CTRLR TSOT23-8 RoHS:是 類別:集成電路 (IC) >> PMIC - 電源控制器，監(jiān)視器 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 應用:多相控制器 輸入電壓:- 電源電壓:9 V ~ 14 V 電流 - 電源:- 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:40-WFQFN 裸露焊盤 供應商設備封裝:40-TQFN-EP（5x5） 包裝:帶卷 (TR) |
| LTC2927CTS8#TRPBF | 功能描述:IC POWER SUPPLY CTRLR TSOT23-8 RoHS:是 類別:集成電路 (IC) >> PMIC - 電源控制器，監(jiān)視器 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 應用:多相控制器 輸入電壓:- 電源電壓:9 V ~ 14 V 電流 - 電源:- 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:40-WFQFN 裸露焊盤 供應商設備封裝:40-TQFN-EP（5x5） 包裝:帶卷 (TR) |
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