- 您现在的位置：买卖IC网 > PDF目录13577 > MAX8715EUA+T (Maxim Integrated Products)IC REG BOOST ADJ 0.8A 8UMAX PDF资料下载
参数资料
| 型号： | MAX8715EUA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 11/14页 |
| 文件大小： | 0K |
| 描述： | IC REG BOOST ADJ 0.8A 8UMAX |
| 标准包装： | 2,500 |
| 类型： | 升压（升压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 2.6 V ~ 12 V |
| 输入电压： | 2.6 V ~ 5.5 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 640kHz, 1.22MHz |
| 电流 - 输出： | 1.8A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-TSSOP，8-MSOP（0.118"，3.00mm 宽） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 8-uMAX |
Low-Noise Step-Up DC-DC Converters
9 V ? 3 . 3 V
? 3 . 3 V ? ?
? ? 0 . 85 ?
L = ? ? ? ? ? ? ≈ 6 . 8 μ H
ratio of inductor resistance to other power path resis-
tances, the best LIR can shift up or down. If the induc-
tor resistance is relatively high, more ripple can be
accepted to reduce the number of turns required and
increase the wire diameter. If the inductor resistance is
relatively low, increasing inductance to lower the peak
2
? 9 V ? ? 0 . 15 A × 1 . 2 MHz ? ? 0 . 5 ?
Using the circuit’s minimum input voltage (3V) and esti-
mating efficiency of 80% at that operating point:
current can decrease losses throughout the power
path. If extremely thin high-resistance inductors are
used, as is common for LCD-panel applications, the
I IN ( DC , MAX ) =
0.15 A × 9 V
3 V × 0 . 8
≈ 0 . 6 A
best LIR can increase to between 0.5 and 1.0.
Once a physical inductor is chosen, higher and lower
The ripple current and the peak current are:
values of the inductor should be evaluated for efficiency
improvements in typical operating regions.
Calculate the approximate inductor value using the typ-
I RIPPLE =
3 V × ( 9 V ? 3 V )
6 . 8 μ H × 9 V × 1 . 2 MHz
≈ 0 . 25 A
ical input voltage (V IN ), the maximum output current
(I MAIN(MAX) ), the expected efficiency ( η TYP ) taken from
an appropriate curve in the Typical Operating
Characteristics , and an estimate of LIR based on the
I PEAK = 0 . 6 A +
0.25 A
2
≈ 0 . 725 A
? V IN ? ?
? ? η
? V
TYP ?
L = ?
? ?
?
? ? I
V IN ( MIN ) × η MIN
above discussion:
2
V MAIN IN
? V MAIN ? ? MAIN ( MAX ) × f OSC ? ? LIR ?
Choose an available inductor value from an appropriate
inductor family. Calculate the maximum DC input cur-
rent at the minimum input voltage V IN(MIN) using con-
servation of energy and the expected efficiency at that
operating point ( η MIN ) taken from an appropriate curve
in the Typical Operating Characteristics :
I MAIN(MAX) × V MAIN
I IN ( DC , MAX ) =
Diode Selection
The output diode should be rated to handle the output
voltage and the peak switch current. Make sure that the
diode’s peak current rating is at least I PK and that its
breakdown voltage exceeds V OUT . Schottky diodes are
recommended.
Input and Output Capacitor Selection
Low-ESR capacitors are recommended for input
bypassing and output filtering. Low-ESR tantalum
capacitors are a good compromise between cost and
performance. Ceramic capacitors are also a good
choice. Avoid standard aluminum electrolytic capaci-
tors. A simple equation to estimate input and output-
capacitor values for a given voltage ripple is as follows:
L × V MAIN OSC
I RIPPLE =
Calculate the ripple current at that operating point and
the peak current required for the inductor:
V IN ( MIN ) × ( V MAIN ? V IN ( MIN ) )
× f
C ≥
0.5 × L × ?? I PK 2 ??
V RIPPLE × V OUT
I PEAK = I IN ( DC , MAX ) + RIPPLE
R 1 = R 2 ? OUT ? 1 ?
I
2
The inductor ’s saturation current rating and the
MAX1790/MAX8715s ’ LX current limit (I LIM ) should
exceed I PEAK and the inductor’s DC current rating should
exceed I IN(DC,MAX) . For good efficiency, choose an
inductor with less than 0.1 Ω series resistance.
Considering the application circuit in Figure 4, the maxi-
mum load current (I MAIN(MAX) ) is 150mA with a 9V output
and a typical input voltage of 3.3V. Choosing an LIR of 0.5
and estimating efficiency of 85% at this operating point:
where V RIPPLE is the peak-to-peak ripple voltage on the
capacitor.
Output Voltage
The MAX1790/MAX8715 operate with an adjustable
output from V IN to 13V. Connect a resistor voltage-
divider to FB (see the Typical Operating Circuit ) from
the output to GND. Select the resistor values as follows:
? V ?
? V FB ?
where V FB , the boost-regulator feedback set point, is
1.24V. Since the input bias current into FB is typically 0,
______________________________________________________________________________________
11
相关PDF资料 |
PDF描述 |
|---|---|
| MAX6792TPWD0+ | IC REG LIN W/SPR VSR 20-TQFN |
| ABM12DTMT | CONN EDGECARD 24POS R/A .156 SLD |
| 6.3YXJ4700MG412.5X25 | CAP ALUM 4700UF 6.3V 20% RADIAL |
| GSM22DTAI-S189 | CONN EDGECARD 44POS R/A .156 SLD |
| VE-J4L-EX-F4 | CONVERTER MOD DC/DC 28V 75W |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8716ETG | 功能描述:接口 - 专用 RoHS:否 制造商:Texas Instruments 产品类型:1080p60 Image Sensor Receiver 工作电源电压:1.8 V 电源电流:89 mA 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:BGA-59 |
| MAX8716ETG+ | 功能描述:接口 - 专用 RoHS:否 制造商:Texas Instruments 产品类型:1080p60 Image Sensor Receiver 工作电源电压:1.8 V 电源电流:89 mA 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:BGA-59 |
| MAX8716ETG+T | 制造商:Maxim Integrated Products 功能描述:INTERLEAVED HI-EFF AND DUAL PS CNTRLR 24TQFN EP - Tape and Reel |
| MAX8716ETG-T | 制造商:Maxim Integrated Products 功能描述:HIGH-EFFICIENCY, DUAL-POWER-SUPPLY CONTROLLER - Tape and Reel |
| MAX8716EVKIT | 制造商:Maxim Integrated Products 功能描述:HIGH-EFFICIENCY DUAL-POWER-SUPPLY - Rail/Tube |
发布紧急采购，3分钟左右您将得到回复。