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參數(shù)資料
| 型號： | LTC1986 |
| 廠商： | Linear Technology Corporation |
| 英文描述： | 3V/5V SIM Power Supply,Micropower Charge Pump DC/DC Converter(用于3V/5V SMI電源,微功耗電荷泵DC/DC變換器) |
| 中文描述： | 3V/5V SIM卡電源，微功耗電荷泵DC / DC轉(zhuǎn)換器（用于3V/5V管理新措施電源，微功耗電荷泵型DC / DC變換器） |
| 文件頁數(shù)： | 5/8頁 |
| 文件大?。?/td> | 149K |
| 代理商： | LTC1986 |
5
LTC1986
APPLICATIO
S I
N
FOR
ATIO
U
Operation
The LTC1986 is a charge pump DC/DC converter designed
specifically to supply V
CC
power for either 3V or 5V SIM
cards. The part can operate in one of three modes: a low
power shutdown mode which disconnects V
IN
from V
OUT
and actively pulls down the V
OUT
supply, 3V mode which
provides a direct connection between V
IN
and V
OUT
for
powering 3V SIM cards, and 5V mode which provides a
regulated 5V output for powering 5V SIM cards. In 5V
mode, regulation is achieved by sensing the output volt-
age through a resistor divider and enabling the charge
pump as needed to maintain regulation.
When the charge pump is enabled, a 2-phase
nonoverlapping clock controls the internal charge pump
switches. Flying capacitor C1 is charged to V
IN
on phase
one of the clock. On phase two of the clock, C1 is stacked
in series with V
IN
and connected to V
OUT
through an
internal switch. This sequence of charging and discharg-
ing the flying capacitor occurs at a free-running frequency
of 900kHz (typ) and continues until the divided output
voltage reaches the upper trip point of the comparator.
Once the output is in regulation, the charge pump is
disabled. This method of bursting the charge pump on and
off enables the LTC1986 to achieve high efficiency at
extremely low output loads.
W
U
Mode Selection
The operating mode is determined by the voltage applied
to the MODE pin. The MODE pin has three voltage thresh-
olds—all of which are referenced to V
IN
:
Shutdown Mode
V
MODE
< V
IN
/2 – 0.1V
5V Mode
V
IN
/2 + 0.1V < V
MODE
< V
IN
– 1V
3V Mode
V
IN
– 0.25V < V
MODE
For example, if V
IN
= 3V, then the following table applies:
V
MODE
0V to 1.4V
1.6V to 2V
2.75V to 3V
OPERATING MODE
Shutdown Mode
5V Mode
3V Mode (V
OUT
= V
IN
)
The three modes can be selected using two totem pole
digital outputs and two external resistors as shown in
Figure 1.
Shutdown mode disconnects V
IN
from V
OUT
and enables
an internal pull-down device which forces V
OUT
to GND.
To achieve the lowest possible quiescent current in shut-
down mode, the voltage on the MODE pin should be pulled
below 0.4V. 3V mode connects V
OUT
to V
IN
through a 2.5
internal switch. The LTC1986 has the additional capability
of boosting V
OUT
to a regulated 2.9V in 3V mode when the
input voltage drops below 2.85V. This ensures that the 3V
SIM V
CC
specification is not violated if V
IN
drops below
2.7V during transients or low battery conditions.
Figure 1
Capacitor Selection
For best performance, it is recommended that low ESR
capacitors be used for both C
IN
and C
OUT
to reduce noise
and ripple. The C
IN
and C
OUT
capacitors should be either
ceramic or tantalum. Ceramic capacitors will provide the
smallest size for a given capacitance. If the input source
impedance is very low (<0.5
), C
IN
may not be needed.
For best performance, C
OUT
should be 2.2
μ
F or greater.
Ceramic capacitors are also recommended for the flying
capacitor C1 with values between 0.047
μ
F and 0.22
μ
F. If
a small value output capacitor (3.3
μ
F or less) is used, a
small flying capacitor should also be used to prevent high
output ripple in 5V mode. The recommended capacitor
values to minimize board space and cost are: C
IN
= 0.1
μ
F,
C1 = 0.047
μ
F and C
OUT
= 2.2
μ
F (ceramic).
MODE
V
IN
3
6
V
IN
LTC1986
750k
1M
3/5
SHDN
1986 F01
SHDN
0
0
1
1
3/5
0
1
0
1
MODE
SHUTDOWN (I
CC
< 1
μ
A)
SHUTDOWN (I
= 10
μ
A)
V
OUT
= 5V
V
OUT
= V
IN
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC1986ES6#PBF | 制造商:Linear Technology 功能描述:DP-Charge Pump/General Purpose, Cut Tape SIM Pwr Supply in SOT-23 6-lead |
| LTC1986ES6#TR | 功能描述:IC REG BOOST SWITCHED CAP SOT23 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標準包裝:500 系列:- 類型:切換式電容器（充電泵），反相 輸出類型:固定 輸出數(shù):1 輸出電壓:-3V 輸入電壓:2.3 V ~ 5.5 V PWM 型:Burst Mode? 頻率 - 開關(guān):900kHz 電流 - 輸出:100mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 細型，TSOT-23-6 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:TSOT-23-6 其它名稱:LTC1983ES6-3#TRMTR |
| LTC1986ES6#TRM | 功能描述:IC REG BOOST SWITCHED CAP SOT23 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標準包裝:500 系列:- 類型:切換式電容器（充電泵），反相 輸出類型:固定 輸出數(shù):1 輸出電壓:-3V 輸入電壓:2.3 V ~ 5.5 V PWM 型:Burst Mode? 頻率 - 開關(guān):900kHz 電流 - 輸出:100mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 細型，TSOT-23-6 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:TSOT-23-6 其它名稱:LTC1983ES6-3#TRMTR |
| LTC1986ES6#TRMPBF | 功能描述:IC REG BOOST SWITCHED CAP SOT23 RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標準包裝:500 系列:- 類型:切換式電容器（充電泵），反相 輸出類型:固定 輸出數(shù):1 輸出電壓:-3V 輸入電壓:2.3 V ~ 5.5 V PWM 型:Burst Mode? 頻率 - 開關(guān):900kHz 電流 - 輸出:100mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 細型，TSOT-23-6 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:TSOT-23-6 其它名稱:LTC1983ES6-3#TRMTR |
| LTC1986ES6#TRPBF | 功能描述:IC REG BOOST SWITCHED CAP SOT23 RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標準包裝:20 系列:SIMPLE SWITCHER® 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:12V 輸入電壓:4 V ~ 60 V PWM 型:電壓模式 頻率 - 開關(guān):52kHz 電流 - 輸出:1A 同步整流器:無 工作溫度:-40°C ~ 125°C 安裝類型:通孔 封裝/外殼:16-DIP（0.300"，7.62mm） 包裝:管件 供應(yīng)商設(shè)備封裝:16-DIP 其它名稱:*LM2575HVN-12LM2575HVN-12 |
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