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| 型号： | MAX1876AEEG+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 16/22页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 24-QSOP |
| 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 |
| 电源电压： | 4.5 V ~ 23 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： | 24-SSOP（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
Dual 180° Out-of-Phase Buck Controllers with
Sequencing/Prebias Startup and POR
inductor ’s saturation rating must exceed the peak-
inductor current at the maximum defined load current
(I LOAD(MAX) ):
R FBI =
P FB × V OUT
5 × 10 - 6 ( 1 - P FB )
I PEAK LOAD ( MAX ) + ?
? LIR ?
? 2 ? LOAD ( MAX )
V OUT ITH FB ) ]
= I ? I
and
R ILIM =
[
10 × V ITH ( 1 - P FB ) × R FBI
- 10 × V ( 1 - P
Setting the Valley Current Limit
The minimum current-limit threshold must be high
enough to support the maximum expected load current
with the worst-case low-side MOSFET on-resistance
value since the low-side MOSFET’s on-resistance is
used as the current-sense element. The inductor’s valley
current occurs at I LOAD(MAX) minus half of the ripple
current. The current-sense threshold voltage (V ITH )
should be greater than voltage on the low-side MOSFET
during the ripple-current valley:
If R ILIM_ results in a negative number, select a low-side
MOSFET with lower R DS(ON) or increase P FB_ or a com-
bination of both for the best compromise of cost, effi-
ciency, and lower power dissipation during short circuit.
Input Capacitor
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
V ITH > R DS ( ONMAX ) × I LOAD ( MAX ) × ? 1 -
?
2 ?
,
?
LIR ?
?
requirement (I RMS ) imposed by the switching currents
as defined by the following equation:
where R DS(ON) is the on-resistance of the low-side
MOSFET (N L ). Use the maximum value for R DS(ON)
from the low-side MOSFET’s data sheet, and additional
margin to account for R DS(ON) rise with temperature is
also recommended. A good general rule is to allow
0.5% additional resistance for each °C of the MOSFET
junction temperature rise.
Connect ILIM_ to VL for the default 100mV (typ) cur-
rent-limit threshold. For an adjustable threshold, con-
nect a resistor (R ILIM _) from ILIM_ to GND. The
relationship between the current-limit threshold (V ITH _)
and R ILIM _ is:
V OUT ( V IN - V OUT )
I RMS = I LOAD
V IN
I RMS has a maximum value when the input voltage equals
twice the output voltage (V IN = 2V OUT ), so I RMS(MAX) =
I LOAD / 2. For most applications, nontantalum capacitors
(ceramic, aluminum, polymer, or OS-CON) are preferred
at the input due to their robustness with high inrush cur-
rents typical of systems that can be powered from very
low impedance sources. Additionally, two (or more)
smaller-value low-ESR capacitors can be connected in
parallel for lower cost. Choose an input capacitor that
exhibits less than +10°C temperature rise at the RMS
R ILIM _ =
V ITH _
0 . 5 μ A
input current for optimal long-term reliability.
Output Capacitor
The key selection parameters for the output capacitor
where R ILIM _ is in ? and V ITH _ is in V.
An R ILIM resistance range of 100k ? to 600k ? corre-
sponds to a current-limit threshold of 50mV to 300mV.
When adjusting the current limit, 1% tolerance resistors
minimize error in the current-limit threshold.
For foldback current limit, a resistor (R FBI ) is added
from ILIM pin to output. The value of R ILIM and R FBI
can then be calculated as follows:
First select the percentage of foldback, P FB , from 15%
to 30%, then:
are capacitance value, ESR, and voltage rating. These
parameters affect the overall stability, output ripple volt-
age, and transient response. The output ripple has two
components: variations in the charge stored in the out-
put capacitor, and the voltage drop across the capaci-
tor’s ESR caused by the current flowing into and out of
the capacitor:
V RIPPLE ? V RIPPLE ( ESR ) + V RIPPLE ( C )
16
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1876EEG | 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX1876EEG+ | 功能描述:电压模式 PWM 控制器 Dual 180 Out PWM Step-Down RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1876EEG+T | 功能描述:电压模式 PWM 控制器 Dual 180 Out PWM Step-Down RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1876EEG-G05 | 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX1876EEG-T | 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
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