参数资料
| 型号： | SC121ULTRT |
| 厂商： | Semtech |
| 文件页数： | 16/23页 |
| 文件大小： | 0K |
| 描述： | IC REG BOOST SYNC 3.3V/ADJ 6MLPD |
| 标准包装： | 1 |
| 类型： | 升压（升压） |
| 输出类型： | 两者兼有 |
| 输出数： | 1 |
| 输出电压： | 3.3V，1.8 V ~ 5 V |
| 输入电压： | 0.7 V ~ 4.5 V |
| 频率 - 开关： | 1.2MHz |
| 电流 - 输出： | 500mA |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 6-MLPD-UT |
| 包装： | 标准包装 |
| 供应商设备封装： | 6-MLPD-UT（1.5x2.0） |
| 其它名称： | SC121ULTRTDKR |
SC121
Applications Information
Detailed Description
The SC121 is a synchronous step-up fixed frequency Pulse
Width Modulated (PWM) DC-DC converter utilizing a
The values of the resistors in the voltage divider network
are chosen to satisfy the equation
1.2MHz fixed frequency current mode architecture. It is
designed to provide output voltages in the range 1.8V to
5.0V from an input voltage as low as 0.7V, with a (output
V OUT
1 . 191
1
R 1
R 2
V
unloaded) start up input voltage of 0.85V. Quiescent
current consumption is typically 3.5mA, entirely into the
OUT pin during boost regulation. (See footnote 1 of the
Electrical Characteristics table.)
The regulator control circuitry is shown in the Block
Diagram. It is comprised of a programmable feedback
controller, an internal 1.2MHz oscillator, an n-
channel Field Effect Transistor (FET) between the LX and
GND pins, and a p-channel FET between the LX and OUT
pins. The current flowing through both FETs is monitored
and limited as required for startup and PWM operation.
An external inductor must be connected between the IN
pin and the LX pin.
Output Voltage Selection
The SC121 output voltage can be programmed to an
internally preset value or it can be programmed with
external resistors. The output is internally programmed to
3.3V when the FB pin is connected to GND. Any output
voltage in the range 1.8V to 5.0V can be programmed with
a resistor voltage divider between OUT and the FB pin as
shown in Figure 1.
IN
L1
A large value of R 2 , ideally 590kΩ or larger, is preferred for
stability for V IN within approximately 400mV of V OUT . For
lower V IN , lower resistor values can be used. The values of
R 1 and R 2 can be as large as desired to achieve low quies-
cent current. C FB = 22pF is recommended to improve
transient response.
The Enable Pin
The EN pin is a high impedance logical input that can be
used to enable or disable the SC121 under processor
control. V EN < 0.2V will disable regulation, set the LX pin
in a high-impedance state (turn off both FET switches),
and turn on an active discharge device to discharge the
output capacitor via the OUT pin. Synchronous rectifier
(p-channel FET) bulk switching prevents pass-through
conduction from LX to OUT while disabled. V EN > 0.85V
will enable the output. The startup sequence from the
EN pin is identical to the startup sequence from the appli-
cation of input power.
LX
EN
OUT
R 1
C FB
V OUT
C IN
GND
SC121
FB
R 2
C OUT
Figure 1 — Output Voltage Feedback Circuit
16
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SC122 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Low Voltage Synchronous Boost Converter |
| SC1225-1001F | 制造商:Lista International Corp 功能描述:SC Cabinet Combination |
| SC122EVB | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Low Voltage Synchronous Boost Converter |
| SC122ULTRT | 功能描述:IC REG BST SYNC 3.3V 95MA 6MLPD RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2 |
| SC-1230 | 制造商:Nidec Copal 功能描述:SWIT ROTARY 16 SLOT SHAFT PC PINS 0.1A 5VDC - Bulk |
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