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| 型号： | MAX8550AETI+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 19/29页 |
| 文件大小： | 0K |
| 描述： | IC PWR SUP DDR INTEG 28TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 应用： | 控制器，DDR |
| 输入电压： | 2 V ~ 28 V |
| 输出数： | 2 |
| 输出电压： | 1.8V，2.5V，0.7 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-TQFN-EP（5x5） |
| 包装： | 管件 |
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Integrated DDR Power-Supply Solution for
Desktops, Notebooks, and Graphic Cards
tem, tantalum input capacitors are acceptable. In either
LX
L
V OUT
configuration, choose a capacitor that has less than
10°C temperature rise at the RMS input current for opti-
mal reliability and lifetime.
MAX8550A
DL
Q2
C OUT
Output Capacitor Selection (Buck)
PGND1
GND
OUT
FB
R C
The output filter capacitor must have low enough equiv-
alent series resistance (R ESR ) to meet output ripple and
load-transient requirements, yet have high enough ESR
to satisfy stability requirements.
For processor core voltage converters and other appli-
cations in which the output is subject to violent load
transients, the output capacitor’s size depends on how
much R ESR is needed to prevent the output from dip-
ping too low under a load transient. Ignoring the sag
due to finite capacitance:
R D
R ESR ≤
V STEP
Δ I LOAD ( MAX )
Figure 6. Setting VOUT with a Resistive Voltage-Divider
Find a low-loss inductor with the lowest possible DC
resistance that fits in the allotted dimensions. Ferrite
cores are often the best choice, although powdered
iron is inexpensive and can work well at frequencies up
to 200kHz. The core must be large enough not to satu-
rate at the peak inductor current (I PEAK ):
In applications without large and fast load transients,
the output capacitor’s size often depends on how much
R ESR is needed to maintain an acceptable level of out-
put voltage ripple. The output ripple voltage of a step-
down controller is approximately equal to the total
inductor ripple current multiplied by the output capaci-
tor’s R ESR . Therefore, the maximum R ESR required to
meet ripple specifications is:
I PEAK LOAD ( MAX ) ? 1 +
= I
?
?
?
LIR ?
2 ?
R ESR ≤
V RIPPLE
I LOAD ( MAX ) × LIR
V OUT ( V IN - V OUT )
Most inductor manufacturers provide inductors in stan-
dard values, such as 1.0μH, 1.5μH, 2.2μH, 3.3μH, etc.
Also look for nonstandard values, which can provide a
better compromise in LIR across the input voltage range.
If using a swinging inductor (where the no-load induc-
tance decreases linearly with increasing current), evalu-
ate the LIR with properly scaled inductance values.
Input Capacitor Selection (Buck)
The input capacitor must meet the ripple current
requirement (I RMS ) imposed by the switching currents:
I RMS = I LOAD
V IN
I RMS has a maximum value of I LOAD / 2 when V IN = 2 ×
V OUT . For most applications, nontantalum capacitors
(ceramic, aluminum, POS, or OSCON) are preferred
due to their resistance to power-up surge currents typi-
cal of systems with a mechanical switch or connector in
series with the input. If the MAX8550A is operated as
the second stage of a two-stage power conversion sys-
The actual capacitance value required relates to the
physical size needed to achieve low ESR, as well as to
the chemistry of the capacitor technology. Thus, the
capacitor is usually selected by ESR and voltage rating
rather than by capacitance value (this is true of tanta-
lums, OSCONs, polymers, and other electrolytics).
When using low-capacity filter capacitors, such as
ceramic capacitors, size is usually determined by the
capacity needed to prevent V SAG and V SOAR from
causing problems during load transients. Generally,
once enough capacitance is added to meet the over-
shoot requirement, undershoot at the rising load edge
is no longer a problem (see the V SAG and V SOAR equa-
tions in the Transient Response section). However, low-
capacity filter capacitors typically have high-ESR zeros
that can affect the overall stability (see the Stability
Requirements section).
______________________________________________________________________________________
19
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8550AETI+ | 功能描述:电压模式 PWM 控制器 Integrated DDR Power Supply Solution 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 |
| MAX8550AETI+T | 功能描述:电压模式 PWM 控制器 Integrated DDR Power Supply Solution 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 |
| MAX8550AETI-T | 功能描述:PMIC 解决方案 RoHS:否 制造商:Texas Instruments 安装风格:SMD/SMT 封装 / 箱体:QFN-24 封装:Reel |
| MAX8550ETI | 功能描述:PMIC 解决方案 RoHS:否 制造商:Texas Instruments 安装风格:SMD/SMT 封装 / 箱体:QFN-24 封装:Reel |
| MAX8550ETI+ | 功能描述:电压模式 PWM 控制器 Integrated DDR Power Supply Solution 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 |
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