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| 型号： | AS7620B-BQFT |
| 厂商： | ams |
| 文件页数： | 11/16页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK 3.3V 0.5A 12MLPQ |
| 设计资源： | Design Support Tool |
| 标准包装： | 6,000 |
| 类型： | 降压（降压） |
| 输出类型： | 固定 |
| 输出数： | 1 |
| 输出电压： | 3.3V |
| 输入电压： | 3.6 V ~ 32 V |
| PWM 型： | 混合物 |
| 电流 - 输出： | 500mA |
| 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： | 12-VQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 12-MLPQ（4x4） |
AS7620
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
9 Application Information
9.1 Input Capacitors
An input capacitor is required to sustain the peak current requested by the turning on of the internal PMOS. When used, the capacitor helps to
reduce the noise and saves the input battery life. The input capacitor has to withstand the input RMS current, which can be calculated by the
following formula:
Irms = I OUT ? --------------------------------------------------
V OUT ? ( V IN – V OUT )
V IN
(EQ 4)
While designing for wide input/output voltage range, the worst case of Irms=1/2*I OUT must be considered. Suggested capacitors are low ESR
OSCON, polymer, aluminum or MLCCs. Tantalum types are not recommended for their weakness in withstanding big inrush currents.
9.2 Output Inductor
The inductor together with the output capacitor represents the output filter. Using the AS7620, the inductor is charged and completely discharged
at every switching cycle being that the converter is forced to work in DCM. Values from 10μH to 100μH are suitable to work with AS7620 and its
selection should consider the following statements:
Bigger inductor implies lower f sw
Bigger inductor implies lower bandwidth
? IL
I OUT + -----------
The inductor must be rated to withstand the peak current (ILIM) and the RMS current Irms =
2
3
2
ILIM ? L
1
9.3 Output Capacitor
The output capacitor together with the inductor represents the output filter. The bigger the capacitance is, the lower will be the output ripple.
Usually, low ESR MLCCs are preferred as they are inexpensive and small in size. Any value from 10μF is suitable, considering the load transient
specifications of the application as well.
9.4 Free Wheeling Diode
2
The inductor current is forced through the diode during the off-times. The average current flowing through it is --- ? fsw ? ------------------------
2 V OUT
The reverse voltage must be higher than the input voltage and safely it is common to consider 30% more. Normally, a schottky diode is preferred
because of its low forward voltage.
9.5 Stability
Even though the hysteretic voltage mode is intrinsically stable, an excessive noise at the FB could cause instability. For this reason care must be
taken drawing the layout, reducing the noise and shielding the FB path from it. The main noise generator is the switching node, which is
commutated from GND to V IN by the internal PMOS and the free wheeling diode and through which a pulse current flows. It is wise to add a
MLCC capacitor as close as possible to the V IN pin of the device and provide a wide/short path between the LX pin and the external components
(inductor and diode). It is preferable to draw the FB path as far as possible from the LX node and, perhaps, shielding it with a GND track. Another
recommendation is to use low ESL output capacitors, thus avoiding electrolytic parts. A big ESL adds a square wave contribution on the FB that
can make the device work improperly.
9.6 100% Duty Cycle Operation
Thanks to the PMOS structure of the internal switch, the device can actually work at 100% duty cycle. This feature is very helpful during the load
transient, because the maximum power can be transferred to the output in order to recover as fastest. The device will try to work at 100% duty
whenever the FB voltage is lower than the upper window’s threshold. Moreover, in this condition, the safety is always guaranteed by the current
limit.
www.ams.com/DC-DC_Step-Up/AS7620
Revision 1.18
11 - 16
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AS7620BBQFT500 | 制造商:AMS 功能描述:IC STEP-DOWN DC/DC CONVERTER MLPQ-12 制造商:AMS 功能描述:IC, STEP-DOWN DC/DC CONVERTER, MLPQ-12; Primary Input Voltage:24V; No. of Outputs:1; Output Voltage:3.3V; Output Current:500mA; No. of Pins:12; Operating Temperature Min:-40C; Operating Temperature Max:125C; Package / Case:12-MLPQ ;RoHS Compliant: Yes |
| AS7620B-BQFT-500 | 功能描述:IC REG BUCK 3.3V 0.5A 12MLPQ 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 |
| AS7620EB | 制造商:AMS 功能描述:Evaluation Board for AS7620 High Voltage Step-Down Converter |
| AS7620QF_EK_ST | 功能描述:AS7620 - DC/DC, Step Down with LDO 1, Non-Isolated Outputs Evaluation Board 制造商:ams 系列:- 零件状态:有效 主要用途:DC/DC，LDO 步降 输出和类型:1，非隔离 功率 - 输出:- 电压 - 输出:- 电流 - 输出:- 电压 - 输入:3.6 V ~ 32 V 稳压器拓扑:降压 频率 - 开关:- 板类型:完全填充 所含物品:板 使用的 IC/零件:AS7620 标准包装:1 |
| AS762R0FLF | 制造商:TT Electronics / IRC 功能描述:AS762R0FLF |
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