- 您现在的位置：买卖IC网 > PDF目录5135 > MAX8720EEI+T (Maxim Integrated Products)IC CNTRL VID STP DWN 28-QSOP PDF资料下载
参数资料
| 型号： | MAX8720EEI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 24/31页 |
| 文件大小： | 0K |
| 描述： | IC CNTRL VID STP DWN 28-QSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 应用： | 控制器，CPU GPU |
| 输入电压： | 2 V ~ 28 V |
| 输出数： | 1 |
| 输出电压： | 0.28 V ~ 1.85 V |
| 工作温度： | 0°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-QSOP |
| 供应商设备封装： | 28-QSOP |
| 包装： | 带卷 (TR) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页当前第24页第25页第26页第27页第28页第29页第30页第31页
Dynamically Adjustable 6-Bit VID
Step-Down Controller
value also determines the load-current value at
which PFM/PWM switchover occurs.
Inductor Selection
The amount of overshoot during a full-load to no-load
transient due to stored inductor energy can be calculat-
ed as:
The switching frequency and inductor operating point
determine the inductor value as follows:
V SOAR ≈
( ? I LOAD(MAX ) ) 2 L
2 C OUT V OUT
L =
V OUT ( V IN ? V OUT )
V IN f SW I LOAD ( MAX ) LIR
Setting the Current Limit
The minimum current-limit threshold must be great
For example: I LOAD(MAX) = 15A, V IN = 12V, V OUT =
1.25V, f SW = 300kHz, 30% ripple current or LIR = 0.3
enough to support the maximum load current when the
current limit is at the minimum tolerance value. The
peak inductor current occurs at I LOAD(MAX) plus half
L =
= 0.8 3 μ H
I LIMIT ( LOW ) > I LOAD ( MAX ) ? 1 ?
?
1.2 5V × (1 2V ? 1.2 5V)
1 2V × 3 0 0k H z × 1 5A × 0.3
Find a low-loss inductor with the lowest possible DC
the ripple current; therefore:
?
?
LIR ?
2 ?
resistance that fits in the allotted dimensions. Ferrite
cores are often the best choice, although powdered
iron is inexpensive and can work well at 200kHz. The
core must be large enough not to saturate at the peak
inductor current (I PEAK ):
where I LIMIT(LOW) equals the minimum current-limit
threshold voltage divided by the R DS(ON) of N L . For the
100mV default setting, the minimum current-limit
threshold is 90mV.
I PEAK LOAD ( MAX ) ? 1 +
= I
?
?
?
LIR ?
2 ?
Connect ILIM to V CC for a default 100mV current-limit
threshold. For an adjustable threshold, connect a resis-
tor-divider from REF to GND, with ILIM connected to the
center tap. The external adjustment range of 0.5V to 2.0V
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
inductance decreases linearly with increasing current),
evaluate the LIR with properly scaled inductance values.
Transient Response
The inductor ripple current also impacts transient-
response performance, especially at low V IN - V OUT dif-
ferentials. Low inductor values allow the inductor
current to slew faster, replenishing charge removed
from the output filter capacitors by a sudden load step.
The total output-voltage sag is the sum of the voltage
sag while the inductor is ramping up and the voltage
sag before the next pulse can occur.
corresponds to a current-limit threshold of 50mV to
200mV. When adjusting the current limit, use 1% toler-
ance resistors and a 10μA divider current to prevent a
significant increase of errors in the current-limit tolerance.
Output Capacitor Selection
The output filter capacitor must have low enough equiv-
alent series resistance (ESR) to meet output ripple and
load-transient requirements, yet have high enough ESR
to satisfy stability requirements. The output capaci-
tance must be high enough to absorb the inductor
energy while transitioning from full-load to no-load con-
ditions without tripping the overvoltage fault protection.
When using high-capacitance, low-ESR capacitors (see
the Output-Capacitor Stability Requirements section),
the filter capacitor’s ESR dominates the output voltage
ripple. Thus, the output capacitor’s size depends on
the maximum ESR required to meet the output-voltage-
L ( ? I LOAD ( MAX ) ) ? K OUT + t OFF ( MIN ) ?
? ? V IN ? V OUT ? ?
2 C OUT OUT ? K ? ? ? t OFF ( MIN ) ?
? ? ?
? ?
V RIPPLE ( P ? P ) = R ESR ILOAD ( MAX ) LIR
V SAG =
V
? V ?
? V IN ?
V IN ?
ripple (V RIPPLE(P-P) ) specifications:
I
In CPU V CORE converters and other applications where
the output is subject to violent load transients, the out-
where t OFF(MIN) is the minimum off-time (see the
Electrical Characteristics ) and K is from Table 3.
put capacitor’s size typically depends on how much
ESR is needed to prevent the output from dipping too
24
______________________________________________________________________________________
相关PDF资料 |
PDF描述 |
|---|---|
| RCC40DRAS | CONN EDGECARD 80POS R/A .100 SLD |
| MAX8720ETX+T | IC CNTRL VID STP DWN 36-TQFN |
| MAX17482GTL+T | IC CTLR PWM DUAL IMVP-6.5 40TQFN |
| 200MXG2200MEFCSN35X45 | CAP ALUM 2200UF 200V 20% SNAP-IN |
| MAX17082GTL+T | IC CTLR PWM DUAL IMVP-6.5 40TQFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8720ETX | 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 |
| MAX8720ETX+ | 功能描述:DC/DC 开关控制器 Dyn Adj 6-Bit VID Step-Down Controller 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 |
| MAX8720ETX+T | 功能描述:DC/DC 开关控制器 Dyn Adj 6-Bit VID Step-Down Controller 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 |
| MAX8720ETX-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 |
| MAX8720EVKIT | 功能描述:DC/DC 开关控制器 Evaluation Kit for the MAX8720 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 |
发布紧急采购，3分钟左右您将得到回复。