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参数资料
| 型号： | MAX1889ETE+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 22/32页 |
| 文件大小： | 0K |
| 描述： | IC PWR SUP TRPL LCD 16-TQFN |
| 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： | 3 |
| 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： | 16-WQFN 裸露焊盘 |
| 供应商设备封装： | 16-TQFN-EP（5x5） |
| 包装： | 带卷 (TR) |
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Triple-Output TFT LCD Power Supply
with Fault Protection
I LOAD ( MAX ) = ? I DRV - BE ? β MIN
I DRIVE ( MIN ) =
The transistor ’ s current gain limits the guaranteed maxi-
mum output current to:
? V ?
? R BE ?
where I DRV is the minimum base-drive current, and R BE
is the pullup resistor connected between the transis-
tor ’ s base and emitter. Furthermore, the transistor ’ s cur-
rent gain increases the linear regulator ’ s DC loop gain
(see the Stability Requirements section), so excessive
gain destabilizes the output. Therefore, transistors with
current gain over 100 at the maximum output current
are not recommended. The transistor ’ s input capaci-
tance and input resistance also create a second pole,
which could be low enough to make the output unsta-
ble when heavily loaded.
During startup, the LDO outputs are below their respec-
tive setpoints, and the base drive to the pass transis-
tors is a maximum. The large drive currents can cause
the charge-pump outputs to collapse. If the charge-
pump loading is objectionable, base resistors can be
added between the drive outputs (DRVN and DRVP)
and the pass transistors (Figure 7). These resistors limit
the maximum drive current and prevent discharging the
charge pump ’ s output capacitors. Select the minimum
base drive current to meet the maximum required LDO
output current:
I LDOOUT(MAX)
β MIN
The resistance required to guarantee this base current is:
The transistor ’ s saturation voltage at the maximum output
current determines the minimum input-to-output voltage
differential that the linear regulator supports.
Alternatively, the package ’ s power dissipation could limit
the usable maximum input-to-output voltage differential.
The maximum power dissipation capability of the transis-
R BASE ≤
=
V LDOIN ( MAX ) - V BE
I DRIVE ( MIN )
β MIN ( V LDOIN ( MAX ) - V BE
I LDOOUT ( MAX )
)
tor ’ s package and mounting must exceed the actual
power dissipation in the device. The power dissipation
equals the maximum load current times the maximum
input-to-output voltage differential:
P = I LOAD ( MAX ) ( V LDOIN - V LDOOUT ) =
I LOAD ( MAX ) V CE
V N
C24
2200pF
As a consequence of adding the base resistors, a volt-
age change at DRVN and DRVP accompanies changes
in drive current. This voltage change can be coupled
through parasitic capacitance to the LDO feedback
pins. If the rate of voltage change is sufficiently large, it
can cause instability.
V P
C20
470pF
MAX1889
V NL
Q1
R19
15k ?
7
6
DRVN
FBN
DRVP
FBP
8
9
R20
51k ?
Q2
V PL
REF
Figure 7. Limiting LDO Drive Current During Startup
22
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相关代理商/技术参数 |
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|---|---|
| MAX1889EVKIT | 功能描述:电源管理IC开发工具 MAX1889 Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| MAX188ACAP | 功能描述:模数转换器 - ADC Integrated Circuits (ICs) RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| MAX188ACAP+ | 功能描述:模数转换器 - ADC 12-Bit 8Ch 133ksps 5.25V Precision ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| MAX188ACAP+T | 功能描述:模数转换器 - ADC 12-Bit 8Ch 133ksps 5.25V Precision ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| MAX188ACAP-T | 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
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