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参数资料
| 型号： | MAX1956ETI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 14/22页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 28-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| PWM 型： | 电压模式 |
| 输出数： | 2 |
| 频率 - 最大： | 660kHz |
| 占空比： | 97% |
| 电源电压： | 1.6 V ~ 5.5 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 ~ 85°C |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
1.6V to 5.5V Input, 0.5% Accurate, Dual
180° Out-of-Phase Step-Down Controllers
Design Procedure
Setting the Output Voltage
Output voltage is set with a resistor-divider, as shown in
Figure 4. The output voltage can be set to as low as
V OUT_
R Y
0.8V. The maximum output voltage is limited by maxi-
mum duty cycle and external component selection.
Select R X (the resistor from FB to GND) between 8k ?
and 10k ? , and calculate R Y from:
R X
FB_
COMP_
R C
C F
C c
R Y = R X × ? OUT - 1 ?
? V ?
? 0 . 8 ?
Inductor Selection
Three key inductor parameters must be specified for
operation with the MAX1955/MAX1956: inductance
value (L), peak inductor current (I PEAK ), and DC resis-
tance (R DC ). A good compromise between size and
efficiency is to set the inductor peak-to-peak ripple cur-
rent equal to 30% of maximum load current, thus LIR =
0.3. The switching frequency, input voltage, output
voltage, and selected LIR determine the inductor value
as follows:
Figure 4. Feedback Divider Network and Compensation
Circuitry
Input Capacitor Selection
The input filter capacitor reduces peak currents drawn
from the power source and reduces noise and voltage
ripple on the input caused by the circuit ’ s switching.
The input capacitor must meet the ripple current
requirement (I RMS ) imposed by the switching currents
defined by the following equation:
( I OUT 1 ) 2 × V OUT 1 × ( V IN OUT 1 ) + ( I OUT 2 ) 2
L =
V OUT ( V IN - V OUT )
V IN × f SW × I OUT ( MAX ) × LIR
I RMS =
1
V IN
- V
× V OUT 2 × ( V IN - V OUT 2 )
where f SW is the switching frequency (typically 600kHz).
I PEAK = I OUT ( MAX ) + ?
? × I OUT ( MAX )
The exact inductor value is not critical and can be
adjusted in order to make trade-offs among size, cost,
and efficiency. Lower inductor values minimize size and
cost, and also improve transient response, but reduce
efficiency and increase output voltage ripple because of
higher peak currents. Higher inductance increases effi-
ciency by reducing the RMS current. However, resistive
losses because of extra wire turns could exceed the
benefit gained from lower AC current levels, especially
when the inductance is increased without also allowing
larger inductor dimensions.
Find a low-loss inductor with the lowest possible DC
resistance that fits in the allotted dimensions. The
inductor ’ s saturation current rating must exceed the
peak inductor current at the maximum defined load
current (I LOAD(MAX) ):
? LIR ?
? 2 ?
Output Capacitor Selection
The key selection parameters for the output capacitor
are the actual capacitance value, the ESR, the ESL,
and the voltage-rating requirements, which affect the
overall stability, output ripple voltage, and transient
response.
The output ripple has three components: variations in
the charge stored in the output capacitor, the voltage
drop across the capacitor ’ s ESR, and the voltage drop
across the capacitor ’ s ESL caused by the current into
and out of the capacitor:
V RIPPLE = V RIPPLE ( ESR ) + V RIPPLE ( C ) + V RIPPLE ( ESL )
The output voltage ripple from the ESR is:
V RIPPLE(ESR) = I P-P ? ESR
The output voltage ripple because of the output capaci-
tance is:
V RIPPLE ( C ) =
I P - P
8 × C OUT × f SW
14
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相关代理商/技术参数 |
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|---|---|
| MAX1957EUB | 功能描述:电流型 PWM 控制器 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 |
| MAX1957EUB+ | 功能描述:电流型 PWM 控制器 High-f Current-Mode PWM Buck Controller 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 |
| MAX1957EUB+T | 功能描述:电流型 PWM 控制器 High-f Current-Mode PWM Buck Controller 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 |
| MAX1957EUB-T | 功能描述:电流型 PWM 控制器 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 |
| MAX19586ETN | 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
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