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| 型号： | ADP1850ACPZ-R7 |
| 厂商： | Analog Devices Inc |
| 文件页数： | 20/32页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 32LFCSP |
| 标准包装： | 1 |
| PWM 型： | 电流模式 |
| 输出数： | 2 |
| 频率 - 最大： | 1.725MHz |
| 占空比： | 90% |
| 电源电压： | 2.75 V ~ 20 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 32-WFQFN 裸露焊盘，CSP |
| 包装： | 标准包装 |
| 其它名称： | ADP1850ACPZ-R7DKR |
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ADP1850
The high-side MOSFET transition loss is approximated by the
equation
Data Sheet
The total power dissipation of the high-side MOSFET is the
sum of conduction and transition losses:
P T ?
V IN × I LOAD × ( t R + t F ) × f SW
2
P HS ? P C + P T
The synchronous rectifier, or low-side MOSFET, carries the
t R ?
where:
P T is the high-side MOSFET switching loss power.
t R is the rise time in charging the high-side MOSFET.
t F is the fall time in discharging the high-side MOSFET.
t R and t F can be estimated by
Q GSW
I DRIVER _ RISE
inductor current when the high-side MOSFET is off. The low-
side MOSFET transition loss is small and can be neglected in
the calculation. For high input voltage and low output voltage,
the low-side MOSFET carries the current most of the time.
Therefore, to achieve high efficiency, it is critical to optimize
the low-side MOSFET for low on resistance. In cases where the
power loss exceeds the MOSFET rating or lower resistance is
required than is available in a single MOSFET, connect multiple
t F ?
Q GSW
I DRIVER _ FALL
low-side MOSFETs in parallel. The equation for low-side
MOSFET conduction power loss is
where:
Q GSW is the gate charge of the MOSFET during switching and is
given in the MOSFET data sheet.
I DRIVER_RISE and I DRIVER_FALL are the driver current put out by the
ADP1850 internal gate drivers.
If Q GSW is not given in the data sheet, it can be approximated by
? V ?
P CLS ? ( I LOAD ) 2 × R DSON ? 1 ? OUT ?
? V IN ?
There is also additional power loss during the time, known as
dead time, between the turn-off of the high-side switch and the
turn-on of the low-side switch, when the body diode of the low-
side MOSFET conducts the output current. The power loss in
Q GSW ? Q GD +
Q GS
2
the body diode is given by
P BODYDIODE = V F × t D × f SW × I O
where:
Q GD and Q GS are the gate-to-drain and gate-to-source charges
given in the MOSFET data sheet.
I DRIVER_RISE and I DRIVER_FALL can be estimated by
where:
V F is the forward voltage drop of the body diode, typically 0.7 V.
t D is the dead time in the ADP1850 , typically 30 ns when driving
some medium-size MOSFETs with input capacitance, C iss , of
I DRIVER _ RISE ?
I DRIVER _ FALL ?
where:
V DD ? V SP
R ON _ SOURCE + R GATE
V SP
R ON _ SINK + R GATE
approximately 3 nF. The dead time is not fixed. Its effective
value varies with gate drive resistance and C iss , so P BODYDIODE
increases in high load current designs and low voltage designs.
Then the power loss in the low-side MOSFET is
P LS = P CLS + P BODYDIODE
V DD is the input supply voltage to the driver and is between 2.75 V
and 5 V, depending on the input voltage.
V SP is the switching point where the MOSFET fully conducts;
this voltage can be estimated by inspecting the gate charge
graph given in the MOSFET data sheet.
R ON_SOURCE is the on resistance of the ADP1850 internal driver,
given in Table 1 when charging the MOSFET.
R ON_SINK is the on resistance of the ADP1850 internal driver,
given in Table 1 when discharging the MOSFET.
R GATE is the on gate resistance of MOSFET given in the
Note that MOSFET, R DSON , increases with increasing tempera-
ture with a typical temperature coefficient of 0.4%/ o C. The
MOSFET junction temperature (T J ) rise over the ambient
temperature is
T J = T A + θ JA × P D
where:
θ JA is the thermal resistance of the MOSFET package.
T A is the ambient temperature.
P D is the total power dissipated in the MOSFET.
MOSFET data sheet. If an external gate resistor is added, add
this external resistance to R GATE .
Rev. A | Page 20 of 32
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP1850DP-EVALZ | 功能描述:EVAL BOARD FOR ADP1850DP 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 |
| ADP1850SP-EVALZ | 功能描述:EVAL BOARD FOR ADP1850SP RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| ADP1851ACPZ-R7 | 功能描述:电流型 PWM 控制器 w-range input Synch StepDown DC/DC Cntr RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ADP1851-EVALZ | 功能描述:电源管理IC开发工具 Evaluation Board 1.8V 25A Output RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| ADP1853 | 制造商:AD 制造商全称:Analog Devices 功能描述:Synchronous, Step-Down DC-to-DC Controller |
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