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| 型号： | MAX1997ETJ+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 20/31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： | 60 |
| 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： | 管件 |
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Quintuple/Triple-Output TFT LCD Power Supplies
with Fault Protection and VCOM Buffer
Table 3. Fault Timer Duration
FREQ PIN
PFLT PIN*
FAULT TIMER DURATION (CLOCK CYCLES)
FAULT TIMER DURATION (ms)
GND
GND
2
13
21.8
Unconnected
IN
GND
GND
GND
Unconnected
2 14
2 15
2 14
21.8
21.8
43.6
Unconnected
Unconnected
2
15
43.6
IN
GND
Unconnected
IN**
2 16
2 15
43.6
87.2
Unconnected
IN**
2
16
87.2
IN
IN**
2 17
87.2
* For MAX1997 only.
** The MAX1998 has PFLT internally connected high.
Input Overcurrent Protection
The high-side overcurrent comparator of the
MAX1997/MAX1998 provides input overcurrent protec-
tion when it is used together with the external P-channel
MOSFET switch P1 (Figure 1). Connect resistive volt-
age-dividers from the source and drain of P1 to GND to
set the overcurrent threshold. The center taps of the
dividers are connected to the overcurrent comparator
inputs (OCN and OCP). See Setting the Input
Overcurrent Threshold section for information on calcu-
lating the resistor values. An overcurrent event acti-
vates the fault-protection circuitry. (See the Fault
Protection section.)
Fault Protection
During steady-state operation, if the output of the main
regulator or any of the linear-regulator outputs is below
its respective fault detection threshold, or an input over-
current condition occurs, the MAX1997/MAX1998 acti-
vate an internal fault timer (Figure 8). If any condition or
the combination of conditions indicates a continuous
fault for the fault timer duration (see Table 3), the
MAX1997/MAX1998 set the fault latch, shutting down
all the outputs except the reference and the oscillator.
The fault detection circuit is disabled during the soft-
start time of each regulator. Once the fault condition is
removed, toggle SHDN (below 0.4V) or cycle the input
voltage (below 2.2V) to clear the fault latch and reacti-
vate the device.
Thermal Shutdown
The thermal shutdown feature limits total power dissipa-
tion in the MAX1997/MAX1998. If the junction tempera-
ture T J exceeds +160 ° C, a thermal sensor immediately
activates the fault protection (Figure 2) and sets the
fault latch, which shuts down all the outputs except the
reference, allowing the device to cool down. Once the
device cools down by at least 15 ° C, the fault latch can
be cleared to reactivate the device. Toggling SHDN
(below 0.4V) or cycling the input voltage (below 2.2V)
clears the fault latch.
Design Procedure
Main Step-Up Regulator
Output Voltage Selection
Set the output voltage by connecting a resistive volt-
age-divider from the output (V MAIN ) to GND with the
center tap connected to FB (see Figure 1). Select R8 to
be 1.5k ? or less for optimized transient response. For
higher efficiency, increase R8 to 12k ? and add lag
compensation. (See the Feedback Compensation sec-
tion.) Calculate R7 with the following equation:
R7 = R8 [(V MAIN / V FB ) - 1]
where V FB = 1.242V - (D x 20mV) and
D ≈ (V MAIN - V IN ) / V MAIN .
For example, if V IN = 3V and D ≈ 0.66, then V FB =
1.229V.
Choosing 1.21k ? for R8, R7 is 7.65k ? . Use 7.68k ? for
R7. V MAIN can range from V IN to 13V.
Inductor Selection
The minimum inductance value, peak current rating,
series resistance, and size are factors to consider when
selecting the inductor. These factors influence the con-
verter ’ s efficiency, maximum output load capability, tran-
sient response time, and output voltage ripple. For a
switching frequency of 1.5MHz, use values between
1.8μH and 4.7μH. For a switching frequency of 750kHz,
use values between 3.3μH and 8.2μH. For a switching
frequency of 375kHz, use values between 6.8μH and
15μH.
20
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1997ETJ+ | 功能描述:其他电源管理 Quint/Triple-Out TFT LCD Power Supply 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 |
| MAX1997ETJ+T | 功能描述:LCD 驱动器 Quint/Triple-Out TFT LCD Power Supply RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
| MAX1997ETJ-T | 功能描述:其他电源管理 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 |
| 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 |
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