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| 型号： | MAX17007GTI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 30/35页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR QPWM GRAPHICS 28TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 系列： | Quick-PWM™ |
| 应用： | 电源 |
| 电流 - 电源： | 1.7mA |
| 电源电压： | 4.5 V ~ 26 V |
| 工作温度： | -40°C ~ 105°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（4x4） |
| 包装： | 带卷 (TR) |
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Dual and Combinable QPWM Graphics
Core Controllers for Notebook Computers
INPUT (V IN )
DH_
N H
C IN
INDUCTOR
LX_
L
R DCR
R CS =
R2
R1 + R2
= R DCR
MAX17007 DL_
MAX17008
PGND
N L
D L
R 1
R 2
C EQ
C OUT
L
R DCR = C EQ
[ R1 R2 1 + 1 ]
CSH_
( R ESR PCB ) ≤ ? I V STEP
≥
CSL_
b) LOSSLESS INDUCTOR SENSING
Figure 14. Current-Sense Configurations (Sheet 2 of 2)
Output Capacitor Selection
The output filter capacitor must have low enough effec-
tive series resistance (ESR) to meet output ripple and
load-transient requirements, yet have high enough ESR
to satisfy stability requirements.
In core and chipset converters and other applications
where the output is subject to large-load transients, the
output capacitor’s size typically depends on how much
ESR is needed to prevent the output from dipping too
low under a load transient. Ignoring the sag due to
finite capacitance:
+ R
LOAD ( MAX )
FOR THERMAL COMPENSATION:
R2 SHOULD CONSIST OF AN NTC RESISTOR IN
SERIES WITH A STANDARD THIN-FILM RESISTOR.
rising load edge is no longer a problem (see the V SAG
and V SOAR equations in the Transient Response sec-
tion). Thus, the output capacitor selection requires
carefully balancing capacitor chemistry limitations
(capacitance vs. ESR vs. voltage rating) and cost.
Output Capacitor Stability Considerations
For Quick-PWM controllers, stability is determined by the
in-phase feedback ripple relative to the switching frequen-
cy, which is typically dominated by the output ESR. The
boundary of instability is given by the following equation:
f SW 1
π 2 π R EFF C OUT
In low-power applications, the output capacitor’s size
often depends on how much ESR is needed to maintain
an acceptable level of output ripple voltage. The output
R EFF ≥
1
2 f SW C OUT
? ?
R ESR ≤ ?
? V RIPPLE
? ? ( V IN OUT ) V OUT ? ?
ripple voltage of a step-down controller equals the total
inductor ripple current multiplied by the output capacitor’s
ESR. The maximum ESR to meet ripple requirements is:
V IN f SW L
? V
where f SW is the switching frequency.
With most chemistries (polymer, tantalum, aluminum,
electrolytic), the actual capacitance value required
relates to the physical size needed to achieve low ESR
and the chemistry limits of the selected capacitor tech-
nology. Ceramic capacitors provide low ESR, but the
capacitance and voltage rating (after derating) are
determined by the capacity needed to prevent V SAG
and V SOAR from causing problems during load tran-
sients. Generally, once enough capacitance is added
to meet the overshoot requirement, undershoot at the
R EFF = R ESR + A CS R CS
where C OUT is the total output capacitance, R ESR is the
total ESR of the output capacitors, R CS is the current-
sense resistance, and A CS is the current-sense gain as
determined by the ILIM setting. A CS equals 2, 2.67, 4, and
8 for ILIM settings of 5V, 3.3V, 2V, and GND, respectively.
For a 300kHz application, the effective zero frequency
must be well below 95kHz, preferably below 50kHz. For
the standard application circuit with ceramic output
capacitors, the output ripple cannot be relied upon to
be in phase with the inductor current due to the low
ESR of the ceramic capacitors. Stability is mainly
dependent on the current-sense gain. With ILIM = 2V,
A CS = 4, and an effective current-sense resistance of
approximately 3.5m ? , then the ESR zero works out to:
1/[2 π x (2x330μF + 5 x 10μF) x 4 x 3.5m ? ] = 16kHz
This is well within the stability requirements.
30
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| MAX17008GTI+ | 功能描述:电压模式 PWM 控制器 QPWM Graphics Core Controller 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 |
| MAX17008GTI+T | 功能描述:电压模式 PWM 控制器 QPWM Graphics Core Controller 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 |
| MAX17009GTL+ | 功能描述:其他电源管理 AMD Dual-Phase CPU Controller RoHS:否 制造商:Texas Instruments 输出电压范围: 输出电流:4 mA 输入电压范围:3 V to 3.6 V 输入电流: 功率耗散: 工作温度范围:- 40 C to + 110 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-48 封装:Reel |
| MAX17009GTL+T | 功能描述:其他电源管理 AMD Dual-Phase CPU Controller RoHS:否 制造商:Texas Instruments 输出电压范围: 输出电流:4 mA 输入电压范围:3 V to 3.6 V 输入电流: 功率耗散: 工作温度范围:- 40 C to + 110 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-48 封装:Reel |
| MAX1700EEE | 功能描述:直流/直流开关转换器 1-3 Cell 1A Step-Up DC/DC Converters 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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