- 您现在的位置：买卖IC网 > PDF目录20688 > A4402ELPTR-T (Allegro Microsystems Inc)IC REG DL BUCK/LINEAR 16-TSSOP PDF资料下载
参数资料
| 型号： | A4402ELPTR-T |
| 厂商： | Allegro Microsystems Inc |
| 文件页数： | 8/17页 |
| 文件大小： | 0K |
| 描述： | IC REG DL BUCK/LINEAR 16-TSSOP |
| 标准包装： | 1 |
| 拓扑： | 降压（降压）（1），线性（LDO）（1） |
| 功能： | 任何功能 |
| 输出数： | 2 |
| 频率 - 开关： | 2MHz |
| 电压/电流 - 输出 1： | 3.3 V ~ 5 V，1A |
| 电压/电流 - 输出 2： | 1.8 V ~ 3.3 V，250mA |
| 带 LED 驱动器： | 无 |
| 带监控器： | 无 |
| 带序列发生器： | 无 |
| 电源电压： | 6 V ~ 50 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-TSSOP（0.173"，4.40mm）裸露焊盘 |
| 供应商设备封装： | 16-TSSOP-EP |
| 包装： | 标准包装 |
| 产品目录页面： | 1141 (CN2011-ZH PDF) |
| 其它名称： | 620-1331-6 |
A4402
Constant On-Time Buck Converter
With Integrated Linear Regulator
Functional Description
? R1 + R2 ?
V SW = V FB1 ? ?
,
? (1)
V LIN = V FB2 ? ?
? R3 + R4 ?
.
?
R4
BasicOperation TheA4402containsafixedon-time,adjust-
able voltage buck switching regulator with valley sensing current
mode control, and an adjustable linear regulator designed to run
off the buck regulator output. The constant on-time converter
maintains a constant output frequency because the on-time is
inversely proportional to the supply voltage. As the input voltage
decreases, the on-time is increased, maintaining a relatively con-
stant period. Valley mode current control allows the converter to
achieve very short on-times because current is measured during
the off-time.
The device is enabled via the ENB input. When the ENB pin
is pulled high, the converter starts-up under the control of an
adjustable soft start routine whose ramp time is controlled by an
external capacitor.
Under light load conditions, the switch enters pulse-skipping
mode to ensure regulation is maintained. This effectively changes
the switcher frequency. The frequency also is affected when the
switcher is operating in discontinuous mode. In order to maintain
a wide input voltage range, the switcher period is extended when
either the minimum off-time at low V IN1 , is reached or the mini-
mum on-time at high V IN1 .
Switcher Overcurrent Protection The converter utilizes
pulse-by-pulse valley current limiting, which operates when the
current through the sense resistor rises to V ISEN . During an over-
load condition, the switch is turned on for a period determined
by the constant on-time circuitry. The switch off-time is extended
until the current decays to the current limit value set by the
selection of the sense resistor, at which point the switch turns on
again. Because no slope compensation is required in this control
scheme, the current limit is maintained at a reasonably constant
level across the input voltage range.
Figure 1 illustrates how the current is limited during an overload
condition. The current decay (period with switch off) is propor-
tional to the output voltage. As the overload is increased, the out-
put voltage tends to decrease and the switching period increases.
VIN1 and VIN2 VIN1 is a high voltage input, designed to with -
stand 50 V. Bulk capacitance of at least 10 μF should be used to
decouple input supply VIN1. The VIN2 input is used to supply
the linear regulator and should be connected directly to the output
of the switching regulator when the target for the V SW voltage is
between 3 and 5.5 V. For voltages outside of that range, the bias
supply for the IC is taken from VIN1 directly and affects overall
efficiency.
For applications where the switcher voltage is greater than 5 V, a
second supply between 3 and 5.5 V can be used to supply VIN2
bias current and the linear regulator. Note that the current into the
VIN2 supply must supply both the i dd bias current and any cur-
rent load on the linear regulator.
Output Voltage Selection The output voltage on each of the
two regulators is set by a voltage divider off the regulator output,
as follows:
R2 ?
? ?
? (2)
? ?
In order to maintain accuracy on the regulators the equivalent
impedance on the FB node (R1 parallel with R2) should be
approximately 10 k?.
Inductor current operating at maximum load
Current Limit level
Maximum load
Constant On-Time
Constant period
Time
Inductor current operating in a “soft” overload
Overload
Current Limit level
Constant On-Time
Extended period
Time
Figure 1. Current limiting during overload
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
8
相关PDF资料 |
PDF描述 |
|---|---|
| GBM12DSEF | CONN EDGECARD 24POS .156 EYELET |
| GBM18DRYI | CONN EDGECARD 36POS DIP .156 SLD |
| VLF3014AT-2R2M1R2 | INDUCTOR POWER 2.2UH 1.2A SMD |
| AD586LRZ | IC VREF SERIES PREC 5V 8-SOIC |
| MIC2225-4MYMT TR | IC REG DL BUCK/LINEAR 10MLF |
相关代理商/技术参数 |
参数描述 |
|---|---|
| A4402KLPTR-T | 功能描述:IC REG DL BUCK/LINEAR 16-TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 + 切换式 系列:- 标准包装:2,500 系列:- 拓扑:降压（降压）同步（3），线性（LDO）（2） 功能:任何功能 输出数:5 频率 - 开关:300kHz 电压/电流 - 输出 1:控制器 电压/电流 - 输出 2:控制器 电压/电流 - 输出 3:控制器 带 LED 驱动器:无 带监控器:无 带序列发生器:是 电源电压:5.6 V ~ 24 V 工作温度:-40°C ~ 85°C 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:* |
| A4403 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Valley Current Mode Control Buck Converter |
| A4403_V | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Valley Current Mode Control Buck Converter |
| A4403GEU-T | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Valley Current Mode Control Buck Converter |
| A4403GEUTR-T | 功能描述:IC REG BUCK ADJ 3A 16QFN 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 |
发布紧急采购，3分钟左右您将得到回复。