- 您现在的位置：买卖IC网 > PDF目录17399 > ADP2121-1.85-EVALZ (Analog Devices Inc)BOARD EVALUATION 1.85V ADP2121 PDF资料下载
参数资料
| 型号： | ADP2121-1.85-EVALZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 17/20页 |
| 文件大小： | 0K |
| 描述： | BOARD EVALUATION 1.85V ADP2121 |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 1.85V |
| 电流 - 输出： | 600mA |
| 输入电压： | 2.3 ~ 5.5 V |
| 稳压器拓扑结构： | 降压 |
| 频率 - 开关： | 6MHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | ADP2121 |
ADP2121
APPLICATIONS INFORMATION
The external component selection for the ADP2121 applica-
tions circuit is driven by the load requirement and begins with
the selection of the inductor. After the inductor is chosen, C IN
and C OUT can be selected. Components can be identified using
the selection guide and recommended selection tables in this
section.
INDUCTOR SELECTION
The high switching frequency of the ADP2121 allows for minimal
output voltage ripple, even with small inductors. Inductor sizing
is a trade-off between efficiency and transient response. A small
inductor leads to a larger inductor current ripple, which provides
better transient response but degrades efficiency. Due to the high
switching frequency of the ADP2121, multilayer ceramic inductors
can be used for an overall smaller solution size. Shielded ferrite
core inductors are recommended for their low core losses and
low electromagnetic interference (EMI).
As a guideline, the peak-to-peak current ripple of the inductor
is typically set to
Δ I L = 0.45 × I LOAD (1)
where I LOAD is the maximum output current. The largest ripple
current, ΔI L , occurs at the maximum input voltage.
It is important that the inductor be capable of handling the
maximum peak inductor current, I PK , determined by the
following equation:
I PK = I LOAD(MAX) + Δ I L /2 (2)
The dc current rating of the inductor should be greater than the
calculated I PK to prevent core saturation. The ADP2121 is designed
for applications with a 0.47 μH inductor. Other values are not
recommended, and stable operation over all conditions is not
guaranteed with their use. Table 6 shows the available 0.47 μH
surface-mount inductors that have been tested with the ADP2121.
INPUT CAPACITOR SELECTION
ceramic capacitor, due to its small size and low equivalent series
resistance (ESR). Table 7 offers suggestions for suitable input
capacitors. All capacitors listed in the table are multilayer
ceramic capacitors.
It is recommended that the VIN pin be bypassed with a 2.2 μF
or larger ceramic input capacitor if the supply line has a distri-
buted capacitance of at least 10 μF. If not, then at least a 10 μF
capacitor is recommended on the input supply pin. The input
capacitor can be increased without any limit for better input
voltage filtering. X5R or X7R dielectrics with a voltage rating of
6.3 V or 10 V are recommended. Y5U and Z5U dielectrics are
not recommended, due to their poor temperature and dc bias
characteristics.
OUTPUT CAPACITOR SELECTION
The output capacitor selection affects both the output voltage ripple
and the loop dynamics of the converter. For a given loop crossover
frequency (the frequency at which the loop gain drops to 0 dB),
the maximum voltage transient excursion (overshoot) is inversely
proportional to the value of the output capacitor. The ADP2121
has been designed to operate with small ceramic capacitors in
the 4.7 μF to 10 μF range that have low ESR and equivalent
series inductance (ESL). These components are able, therefore,
to meet stringent output voltage ripple specifications. X5R or
X7R dielectrics with a voltage rating of 6.3 V are recommended.
for ADP2121 applications. The minimum effective capacitance
required for stable operation is 1.5 μF.
When choosing output capacitors, it is also important to account
for the loss of capacitance due to output voltage dc bias. This
may result in using a capacitor with a higher rated voltage to
achieve the desired capacitance value. Additionally, if ceramic
output capacitors are used, the capacitor rms ripple current
rating should always meet the application requirements. The
rms ripple current is calculated as
The input capacitor must be able to support the maximum
input operating voltage and the maximum rms input current.
Select an input capacitor capable of withstanding the rms input
I rms ( COUT ) =
1
2 3
×
V OUT × ( V IN ( MAX ) ? V OUT )
L × f SW × V IN ( MAX )
(4)
current for the maximum load current in the application using
the following equation:
At nominal load currents, the converter operates in pulse
frequency mode (PFM), and the overall output voltage ripple is the
I rms = I OUT ( MAX ) ×
V OUT × ( V IN ? V OUT )
V IN
(3)
sum of the voltage spike caused by the output capacitor ESR plus
the voltage ripple caused by charging and discharging the
output capacitor.
The input capacitor reduces the input voltage ripple caused by
the switch currents on the VIN pin. Place the input capacitor
as close as possible to the VIN pin.
In principle, different types of capacitors can be considered, but for
battery-powered applications, the best choice is the multilayer
Δ V OUT = Δ I L × ( ESR + 1/(8 × C OUT × f SW ))
The largest voltage ripple occurs at the highest input voltage.
At light load currents, if MODE is set low, then the converter
operates in the power-saving mode (PFM), and the output
voltage ripple increases.
(5)
Rev. B | Page 17 of 20
相关PDF资料 |
PDF描述 |
|---|---|
| LQH43CN470K03L | INDUCTOR 47UH 10% 280MA 1812 |
| A9BAG-1502F | FLEX CABLE - AFF15G/AF15/AFE15T |
| IPS6011STRRPBF | IC SWITCH IPS 1CH HI SIDE D2PAK- |
| RB-3.33.3D | CONV DC/DC 1W 3.3VIN +/-3.3VOUT |
| IR3313STRRPBF | IC SWITCH HISIDE PROGR D2PAK-5 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP2121-2.3-EVALZ | 功能描述:BOARD EVAL FOR ADP2121-2.3V RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:* 标准包装:1 系列:- 主要目的:DC/DC，步降 输出及类型:1，非隔离 功率 - 输出:- 输出电压:3.3V 电流 - 输出:3A 输入电压:4.5 V ~ 28 V 稳压器拓扑结构:降压 频率 - 开关:250kHz 板类型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名称:497-12113STEVAL-ISA094V1-ND |
| ADP2121ACBZ-1.82R7 | 功能描述:IC REG BUCK SYNC 1.82V 6WLCSP 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:500 系列:- 类型:切换式电容器（充电泵），反相 输出类型:固定 输出数:1 输出电压:-3V 输入电压:2.3 V ~ 5.5 V PWM 型:Burst Mode? 频率 - 开关:900kHz 电流 - 输出:100mA 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:SOT-23-6 细型，TSOT-23-6 包装:带卷 (TR) 供应商设备封装:TSOT-23-6 其它名称:LTC1983ES6-3#TRMTR |
| ADP2121ACBZ-1.85R7 | 功能描述:IC REG BUCK SYNC 1.85V 6WLCSP 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:500 系列:- 类型:切换式电容器（充电泵），反相 输出类型:固定 输出数:1 输出电压:-3V 输入电压:2.3 V ~ 5.5 V PWM 型:Burst Mode? 频率 - 开关:900kHz 电流 - 输出:100mA 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:SOT-23-6 细型，TSOT-23-6 包装:带卷 (TR) 供应商设备封装:TSOT-23-6 其它名称:LTC1983ES6-3#TRMTR |
| ADP2121ACBZ-1.8-R7 | 功能描述:IC REG BUCK SYNC 1.8V .6A 6WLCSP 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:500 系列:- 类型:切换式电容器（充电泵），反相 输出类型:固定 输出数:1 输出电压:-3V 输入电压:2.3 V ~ 5.5 V PWM 型:Burst Mode? 频率 - 开关:900kHz 电流 - 输出:100mA 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:SOT-23-6 细型，TSOT-23-6 包装:带卷 (TR) 供应商设备封装:TSOT-23-6 其它名称:LTC1983ES6-3#TRMTR |
| ADP2121ACBZ-1875R7 | 功能描述:IC REG BUCK SYNC 1.875V 6WLCSP 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:500 系列:- 类型:切换式电容器（充电泵），反相 输出类型:固定 输出数:1 输出电压:-3V 输入电压:2.3 V ~ 5.5 V PWM 型:Burst Mode? 频率 - 开关:900kHz 电流 - 输出:100mA 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:SOT-23-6 细型，TSOT-23-6 包装:带卷 (TR) 供应商设备封装:TSOT-23-6 其它名称:LTC1983ES6-3#TRMTR |
发布紧急采购，3分钟左右您将得到回复。