参数资料
| 型号： | LT3681EDE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 8/24页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 2A 14DFN |
| 标准包装： | 2,500 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.27 V ~ 20 V |
| 输入电压： | 3.6 V ~ 34 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 300kHz ~ 2.8MHz |
| 电流 - 输出： | 2A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 14-WFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 14-DFN-EP（4x3） |
LT3681
BLOCK DIAGRA
V IN
C1
13
V IN
2
BIAS
INTERNAL 1.265V REF
BD
10
14
RUN/SS
SLOPE COMP
SWITCH
LATCH
BOOST
11
R T
6
RT
OSCILLATOR
300kHz–2.8MHz
R
S
Q
DISABLE
SW
12
C3
L1
V OUT
SOFT-START
BurstMode
DETECT
DC
DC
9
16
C2
1
PG
ERROR AMP
V C CLAMP
DA
8
GND GND
4
7
GND
15
+
–
1.12V
3
FB
+
–
V C
5
C C
R C
C F
R2
R1
3681 BD
OPERATION
The LT3681 is a constant frequency, current mode step-
down regulator. An oscillator, with frequency set by RT,
sets an RS ?ip-?op, turning on the internal power switch.
An ampli?er and comparator monitor the current ?owing
between the V IN and SW pins, turning the switch off when
this current reaches a level determined by the voltage at
V C . An error ampli?er measures the output voltage through
an external resistor divider tied to the FB pin and servos
the V C pin. If the error ampli?er’s output increases, more
current is delivered to the output; if it decreases, less cur-
rent is delivered. An active clamp on the V C pin provides
current limit. The V C pin is also clamped to the voltage on
the RUN/SS pin; soft-start is implemented by generating a
voltage ramp at the RUN/SS pin using an external resistor
and capacitor.
An internal regulator provides power to the control cir-
cuitry. The bias regulator normally draws power from the
V IN pin, but if the BIAS pin is connected to an external
voltage higher than 3V bias power will be drawn from the
external source (typically the regulated output voltage).
This improves ef?ciency. The RUN/SS pin is used to place
the LT3681 in shutdown, disconnecting the output and
reducing the input current to less than 1μA.
The switch driver operates from either the input or from
the BOOST pin. An external capacitor is used to generate
a voltage at the BOOST pin that is higher than the input
supply. This allows the driver to fully saturate the internal
bipolar NPN power switch for ef?cient operation.
To further optimize ef?ciency, the LT3681 automatically
switches to Burst Mode operation in light load situations.
Between bursts, all circuitry associated with controlling
the output switch is shut down reducing the input supply
current to 55μA in a typical application.
The oscillator reduces the LT3681’s operating frequency
when the voltage at the FB pin is low. This frequency
foldback helps to control the output current during startup
and overload.
The LT3681 contains a power good comparator which trips
when the FB pin is at 91% of its regulated value. The PG
output is an open-collector transistor that is off when the
output is in regulation, allowing an external resistor to pull
the PG pin high. Power good is valid when the LT3681 is
enabled and V IN is above 3.6V.
The LT3681 integrates a high quality, 36V, 2A power
Schottky diode to reduce the overall solution size.
3681f
8
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3682 | 制造商:LINER 制造商全称:Linear Technology 功能描述:42V, 750mA Step-Down Regulator with 2.5μA |
| LT3682EDD#PBF | 功能描述:IC REG BUCK ADJ 1A 12DFN 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 |
| LT3682EDD#TRPBF | 功能描述:IC REG BUCK ADJ 1A 12DFN 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:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
| LT3682EDD-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:1A Micropower Step-Down |
| LT3682EDD-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:1A Micropower Step-Down |
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