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| 型号： | MAX5081ATE+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 12/19页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 1A 16TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.23 V ~ 32 V |
| 输入电压： | 7.5 V ~ 40 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 250kHz |
| 电流 - 输出： | 1A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WQFN 裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 16-TQFN-EP（5x5） |
1A, 40V, MAXPower Step-Down
DC-DC Converters
? V OUT
? V FB
R 4 =
?
R 3
?
? 1 ?
?
the input capacitor). The total voltage ripple is the sum
of ? V Q and ? V ESR . Calculate the input capacitance and
ESR required for a specified ripple using the following
equations:
? I OUT_MAX +
? I P-P ?
?
?
where V FB = 1.23V.
Inductor Selection
Three key inductor parameters must be specified for
operation with the MAX5080/MAX5081: inductance
ESR =
?
?
? V ESR
2
value (L), peak inductor current (I PEAK ), and inductor
saturation current (I SAT ). The minimum required induc-
tance is a function of operating frequency, input-to-out-
put voltage differential, and the peak-to-peak inductor
current ( ? I P-P ). Higher ? I P-P allows for a lower inductor
value while a lower ? I P-P requires a higher inductor
where
C IN =
I OUT_MAX × D ( 1 ? D )
? V Q × f SW
value. A lower inductor value minimizes size and cost
and improves large-signal and transient response, but
reduces efficiency due to higher peak currents and
? I P-P =
( V IN ? V OUT ) × V OUT
V IN × f SW × L
and
higher peak-to-peak output voltage ripple for the same
D = OUT
L = OUT IN OUT
output capacitor. On the other hand, higher inductance
increases efficiency by reducing the ripple current.
Resistive losses due to extra wire turns can exceed the
benefit gained from lower ripple current levels especial-
ly when the inductance is increased without also allow-
ing for larger inductor dimensions. A good compromise
is to choose ? I P-P equal to 40% of the full load current.
Calculate the inductor using the following equation:
V (V ? V )
V IN × f SW × ? I P-P
V IN and V OUT are typical values so that efficiency is opti-
mum for typical conditions. The switching frequency (f SW )
is fixed at 250kHz or can vary between 150kHz and
350kHz when synchronized to an external clock (see the
Oscillator/Synchronization Input (SYNC) section). The
peak-to-peak inductor current, which reflects the peak-to-
peak output ripple, is worst at the maximum input voltage.
See the Output Capacitor Selection section to verify that
the worst-case output ripple is acceptable. The inductor
saturating current (I SAT ) is also important to avoid run-
away current during continuous output short circuit.
V
V IN
I OUT_MAX is the maximum output current, D is the duty
cycle, and f SW is the switching frequency.
The MAX5080/MAX5081 includes internal and external
UVLO hysteresis and soft-start to avoid possible unin-
tentional chattering during turn-on. However, use a bulk
capacitor if the input source impedance is high. Use
enough input capacitance at lower input voltages to
avoid possible undershoot below the undervoltage
lockout threshold during transient loading.
Output Capacitor Selection
The allowable output voltage ripple and the maximum
deviation of the output voltage during load steps deter-
mine the output capacitance and its ESR. The output
ripple is mainly composed of ? V Q (caused by the
capacitor discharge) and ? V ESR (caused by the volt-
age drop across the equivalent series resistance of the
output capacitor). The equations for calculating the
peak-to-peak output voltage ripple are:
Select an inductor with an I SAT specification higher than
the maximum peak current limit of 2.6A.
Input Capacitor Selection
? V Q =
? I PP
1 6 × C OUT × f SW
The discontinuous input current of the buck converter
causes large input ripple currents and therefore the
input capacitor must be carefully chosen to keep the
input voltage ripple within design requirements. The
input voltage ripple is comprised of ? V Q (caused by the
capacitor discharge) and ? V ESR (caused by the ESR of
? V ESR = ESR × ? I P-P
Normally, a good approximation of the output voltage
ripple is ? V RIPPLE ≈ ? V ESR + ? V Q . If using ceramic
capacitors, assume the contribution to the output volt-
age ripple from ESR and the capacitor discharge to be
12
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX5081ATE+ | 功能描述:直流/直流开关转换器 1A 40V MAXPower Step-Down RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX5081ATE+T | 功能描述:直流/直流开关转换器 1A 40V MAXPower Step-Down RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX5081ATE-T | 功能描述:直流/直流开关转换器 1A 40V MAXPower Step-Down RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX5082 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:1.5A, 40V, MAXPower Step-Down DC-DC Converters |
| MAX5082ATE | 功能描述:直流/直流开关转换器 1A 40V MAXPower Step-Down RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
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