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| 型号： | MAX1997ETJ+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 21/31页 |
| 文件大小： | 0K |
| 描述： | IC PWR SUPPLY TFT LCD 32TQFN |
| 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，TFT LCD |
| 输入电压： | 2.7 V ~ 5.5 V |
| 输出数： | 5 |
| 输出电压： | 2.7 V ~ 13 V |
| 工作温度： | 0°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 供应商设备封装： | 32-TQFN-EP（5x5） |
| 包装： | 带卷 (TR) |
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Quintuple/Triple-Output TFT LCD Power Supplies
with Fault Protection and VCOM Buffer
ONDC
SHDN
UVLO
R
GATE
REFERENCE READY
THERMAL FAULT
OVERCURRENT FAULT
REG 2 FAULT
REG 1 FAULT
Q
S
FAULT
LATCH
GATE
READY
V CT > V ON2
ENABLES REG 1 LINEAR-REGULATOR
ENABLES REG 2 LINEAR-REGULATOR
ENABLES STEP-UP REGULATOR
REG P FAULT
STEP-UP REGULATOR FAULT
REG N FAULT
V CT > V ONP
ENABLES REG P LINEAR-REGULATOR
CLK
f OSC /128
FREQ
PFLT
R
RIPPLE
COUNTER
FAULT TIMER
STEP-UP REGULATOR
SOFT-START DONE
V CT > V ONN
ENABLES REG N LINEAR-REGULATOR
Figure 8. Startup and Fault Protection Logic
I PEAK = ?
? ? ? +
? 2 ? ? V MAIN ? ? ? ?
? ? ? ?
L = ?
? ? ?
? LIR ?
? V MAIN ? ?
? I
?
× V
P LR = I LAVG 2 R L ? ? MAIN MAIN ? R L
The maximum inductor current, input voltage, output
voltage, and switching frequency determine the induc-
tor value. To ensure an adequate inductor current-
sense signal in the IC, always calculate the inductor
value with the maximum guaranteed inductor current
even though the actual operating current may be much
lower. For the MAX1997/MAX1998, the maximum guar-
anteed inductor current is the minimum value of the
internal LX current limit (1.6A, see the Electrical
Characteristics ). The equations provided here include a
constant defined as LIR, which is the ratio of the peak-
to-peak inductor current ripple to the average DC
inductor current. For a good compromise between the
size of the inductor, power loss, and output voltage rip-
ple, select an LIR of 0.3 to 0.5. The inductance value is
then given by:
? V IN(TYP) ? ? V MAIN - V IN(TYP) ? ? 1 ?
? ? ?
I L(MAX) f OSC
where f OSC is the oscillator frequency (see Elec-
trical Characteristics ), and I L(MAX) is 1.6A. Considering
the typical application circuit, the typical input voltage
is 3.3V, the main output voltage is 9V, and the switching
frequency is 1.5MHz. Based on the above equations,
the inductance value is 4.3μH for an LIR of 0.2. The
inductance value is 1.7μH for an LIR of 0.5. The induc-
tance in the standard application circuit is chosen to be
3.3μH.
The inductor ’ s peak current rating should be higher
than the expected peak inductor current throughout the
normal operating range. The expected peak inductor
current is given by:
? I MAIN(MAX) V MAIN ? ? 1 ?
? V IN(MIN) ? ? η ?
? 1 ? ? V IN(MIN) ? ? V MAIN - V IN(MIN) ?
Lf OSC ?
where η is the efficiency of the regulator. For most
applications, the efficiency is between 75% and 85%.
Under fault conditions, the inductor current may reach
the internal LX current limit (see Electrical Character-
istics ). However, soft saturation inductors and the con-
troller ’ s fast current-limit circuitry protect the device
from failure during such a fault condition.
The inductor ’ s DC resistance can significantly affect
efficiency due to the resistive power loss (P LR ), which
can be approximated by the following equation:
2
? V IN ?
where I LAVG is the average inductor current and R L is
the inductor ’ s series resistance. For best performance,
select inductors with resistance less than the internal
N-channel MOSFET ’ s on-resistance (0.25 ? typ). To
minimize radiated noise in sensitive applications, use a
shielded inductor.
______________________________________________________________________________________
21
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1997EVKIT | 制造商:Maxim Integrated Products 功能描述:QUINTUPLE/TRIPLE OUTPUT TFT LCD POWER SUPPLIE - Bulk |
| MAX19983A | 功能描述:上下转换器 RoHS:否 制造商:Texas Instruments 产品:Down Converters 射频:52 MHz to 78 MHz 中频:300 MHz LO频率: 功率增益: P1dB: 工作电源电压:1.8 V, 3.3 V 工作电源电流:120 mA 最大功率耗散:1 W 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PQFP-128 |
| MAX19985AETX+ | 功能描述:上下转换器 High-Gain 700MHz to 1GHz Downconv RoHS:否 制造商:Texas Instruments 产品:Down Converters 射频:52 MHz to 78 MHz 中频:300 MHz LO频率: 功率增益: P1dB: 工作电源电压:1.8 V, 3.3 V 工作电源电流:120 mA 最大功率耗散:1 W 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PQFP-128 |
| MAX19985AETX+T | 功能描述:上下转换器 High-Gain 700MHz to 1GHz Downconv RoHS:否 制造商:Texas Instruments 产品:Down Converters 射频:52 MHz to 78 MHz 中频:300 MHz LO频率: 功率增益: P1dB: 工作电源电压:1.8 V, 3.3 V 工作电源电流:120 mA 最大功率耗散:1 W 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PQFP-128 |
| MAX19985ETX+ | 功能描述:上下转换器 Dual, SiGe, .7-1GHz Downconversion Mixer RoHS:否 制造商:Texas Instruments 产品:Down Converters 射频:52 MHz to 78 MHz 中频:300 MHz LO频率: 功率增益: P1dB: 工作电源电压:1.8 V, 3.3 V 工作电源电流:120 mA 最大功率耗散:1 W 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PQFP-128 |
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