参数资料
| 型号： | ADP1621ARMZ-R7 |
| 厂商： | Analog Devices Inc |
| 文件页数： | 16/32页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR PWM CM 10-MSOP |
| 标准包装： | 1 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1.5MHz |
| 占空比： | 97% |
| 电源电压： | 2.9 V ~ 5.5 V |
| 降压： | 是 |
| 升压： | 是 |
| 回扫： | 是 |
| 反相： | 是 |
| 倍增器： | 是 |
| 除法器： | 是 |
| Cuk： | 是 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 包装： | 标准包装 |
| 产品目录页面： | 791 (CN2011-ZH PDF) |
| 配用： | ADP1621-EVALZ-ND - BOARD EVALUATION FOR ADP1621 |
| 其它名称： | ADP1621ARMZ-R7DKR |
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ADP1621
The total power dissipation determines the diode junction
Data Sheet
The MOSFET power dissipation due to conduction is thus
I
P C = ? ? LOAD ? ? × D × R DSON × ( 1 + K )
temperature, which is given by
T J , DIODE = T A + P DIODE × θ JA
(17)
? 1 ? D ?
2
(19)
( V OUT + V D ) × I LOAD × ( t R + t F ) × f SW
P SW =
1 ? D
where T J,DIODE is the junction temperature, T A is the ambient tem-
perature, and θ JA is the junction-to-ambient thermal resistance
of the diode package. The diode junction temperature must not
exceed its maximum rating at the given power dissipation level.
For high efficiency, Schottky diodes are recommended. The low
forward-voltage drop of a Schottky diode reduces the power losses
during the MOSFET off time, and the fast switching speed reduces
the switching losses during the MOSFET transitions. However,
for high voltage, high temperature applications where the reverse
leakage current of the Schottky diode can become significant
and degrade efficiency, use an ultrafast-recovery junction diode.
Make sure that the diode is rated to handle the average output
load current. Many diode manufacturers derate the current
capability of the diode as a function of the duty cycle. Verify
that the diode is rated to handle the average output load current
with the minimum duty cycle. Also, ensure that the peak inductor
current is less than the maximum rated current of the diode.
MOSFET SELECTION
When turned on, the external n-channel MOSFET allows
energy to be stored in the magnetic field of the inductor. When
the MOSFET is turned off, this energy is delivered to the load to
boost the output voltage.
The choice of the external power MOSFET directly affects the
boost converter performance. Choose the MOSFET based on
the following: threshold voltage (V T ), on resistance (R DSON ),
maximum voltage and current ratings, and gate charge.
where P C is the conduction power loss, and R DSON is the MOSFET
on resistance. The variable K is a factor that models the increase
of R DSON with temperature:
K = 0 . 005 / ? C × ( T J,MOSFET ? 25 ? C ) (20)
where T J,MOSFET is the MOSFET junction temperature. Note that
multiple n-channel MOSFETs can be placed in parallel to reduce
the effective R DSON .
The power dissipation due to switching transition loss is
approximated by
(21)
2
where P SW is the switching power loss, t R is the MOSFET rise
time, and t F is the MOSFET fall time. The MOSFET rise and fall
times are functions of both the gate drive circuitry and the
MOSFET used in the application.
The total power dissipation of the MOSFET is the sum of the
conduction and transition losses:
P MOSFET = P C + P SW (22)
where P MOSFET is the total MOSFET power dissipation. Ensure
that the maximum power dissipation is significantly less than
the maximum power rating of the MOSFET.
The total power dissipation also determines the MOSFET
junction temperature, which is given by
The minimum operating voltage of the ADP1621 is 2.9 V.
T J , MOSFET = T A + P MOSFET × θ JA
(23)
= LOAD × D
I
1 ? D
? I
?
P CS = ? LOAD ? × D × R CS (24)
Choose a MOSFET with a V T that is at least 0.3 V less than the
minimum input supply voltage at PIN used in the application.
Ensure that the maximum V GS rating of the MOSFET is at least
a few volts greater than the maximum voltage that is applied to
PIN. Ensure that the maximum V DS rating of the MOSFET
exceeds the maximum V OUT by at least 5 V to 10 V. Depending
on parasitics, the MOSFET may be exposed to voltage spikes that
exceed the sum of V OUT and the forward-voltage drop of the diode.
Estimate the rms current in the MOSFET under continuous
conduction mode by
I MOSFET , RMS (18)
where D is the duty cycle. Derate the MOSFET current at least
20% to account for inductor ripple and changes in the forward-
voltage drop of the diode.
where T J,MOSFET is the junction temperature, T A is the ambient
temperature, and θ JA is the junction-to-ambient thermal
resistance of the MOSFET package. The MOSFET junction
temperature must not exceed its maximum rating at the given
power dissipation level.
If lossless current sensing is not used, there will also be power
dissipation in the external current-sense resistor, R CS . The power
dissipation, P CS , in the external resistor due to conduction losses
is given by
2
? 1 ? D ?
LOOP COMPENSATION
The ADP1621 uses external components to compensate the
regulator loop, allowing optimization of the loop dynamics for
a given application.
The step-up converter produces an undesirable right-half plane
(RHP) zero in the regulation feedback loop. This RHP zero
requires compensating the regulator such that the crossover
Rev. B | Page 16 of 32
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP1621-BL2-EVZ | 制造商:Analog Devices 功能描述:BLANK ADISIMPOWER EVAL ADP1621 - Boxed Product (Development Kits) |
| ADP1621-BL4-EVZ | 功能描述:BOARD EVALUATION FOR ADP1621 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 |
| ADP1621-EVAL | 制造商:AD 制造商全称:Analog Devices 功能描述:Constant-Frequency, Current-Mode Step-Up DC/DC Controller |
| ADP1621-EVALZ | 功能描述:BOARD EVALUATION FOR ADP1621 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 |
| ADP162ACBZ-1.2-R7 | 功能描述:IC REG LDO 1.2V .15A 4WLCSP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 系列:- 其它有关文件:LD39015JXX12 View All Specifications 标准包装:1 系列:- 稳压器拓扑结构:正，固定式 输出电压:1.2V 输入电压:1.5 V ~ 5.5 V 电压 - 压降（标准）:- 稳压器数量:1 电流 - 输出:150mA 电流 - 限制（最小）:- 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:4-WFBGA，FCBGA 供应商设备封装:4-覆晶（1.07x1.07） 包装:Digi-Reel® 其它名称:497-11958-6 |
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