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参数资料
| 型号： | MAX1778EUG+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 22/39页 |
| 文件大小： | 0K |
| 描述： | IC DCDC CONV MULTI OUT 24TSSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 62 |
| 应用： | 转换器，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： | 24-TSSOP（0.173"，4.40mm 宽） |
| 供应商设备封装： | 24-TSSOP |
| 包装： | 管件 |
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MAX1778/MAX1880–MAX1885
Quad-Output TFT LCD DC/DC
Converters with Buffer
Negative Charge Pump
During the first half-cycle, the p-channel MOSFET turns
on, and flying capacitor C X(NEG) charges to V SUPN
minus a diode drop (Figure 4). During the second
half-cycle, the p-channel MOSFET turns off, and the
n-channel MOSFET turns on, level shifting C X(NEG) .
This connects C X(NEG) in parallel with reservoir capaci-
tor C OUT(NEG) . If the voltage across C OUT(NEG) minus
a diode drop is greater than the voltage across
C X(NEG) , charge flows from C OUT(NEG) to C X(NEG) until
the diode (D5) turns off. The amount of charge trans-
ferred to the output is controlled by the variable
n-channel on-resistance.
Low-Dropout Linear Regulator (MAX1778/
MAX1881/MAX1883/MAX1884 Only)
The MAX1778/MAX1881/MAX1883/MAX1884 contain a
low-dropout linear regulator (Figure 5) that uses an
internal PNP pass transistor (Q P ) to supply loads up to
40mA. As illustrated in Figure 5, the 1.25V reference is
connected to the error amplifier, which compares this
reference with the feedback voltage and amplifies the
difference. If the feedback voltage is higher than the
reference voltage, the controller lowers the base
current of Q P , which reduces the amount of current to
the output. If the feedback voltage is too low, the
MAX1778
device increases the pass transistor base current,
which allows more current to pass to the output and
increases the output voltage. However, the linear regu-
lator also includes an output current limit to protect the
internal pass transistor against short circuits.
The low-dropout linear regulator monitors and controls
the pass transistor’s base current, limiting the output
current to 130mA (typ). In conjunction with the thermal
overload protection, this current limit protects the
output, allowing it to be shorted to ground for an indefi-
nite period of time without damaging the part.
VCOM Buffer
The MAX1778/MAX1880–MAX1885 include a VCOM
buffer, which uses an operational transconductance
amplifier (OTA) to provide a current output that is ideal
for driving capacitive loads, such as the backplane of a
TFT LCD panel. The unity-gain bandwidth of this
current-output buffer is:
GBW = gm/C OUT
where gm is the amplifier ’s transconductance. The
bandwidth is inversely proportional to the output
capacitor, so large capacitive loads improve stability;
however, lower bandwidth decreases the buffer’s tran-
sient response time. To improve the transient response
MAX1881
MAX1883
MAX1884
SUPL
C SUPL
V SUPL
4.5V TO 15V
THERMAL
SENSOR
CURRENT
LIMIT
Q P
LDOOUT
V LDOOUT
1.25V TO (V SUPL - 0.3V)
C LDOOUT
R7
FBL
ERROR
AMPLIFIER
V REF
R8
(
1.25V
GND
V LDOOUT = 1 +
V REF = 1.25V
R7
R8
)
V REF
Figure 5. Low-Dropout Linear Regulator Block Diagram
22
Maxim Integrated
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1778EUG+ | 功能描述:直流/直流开关转换器 Quad-Output TFT LCD w/Buffer 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 |
| MAX1778EUG+T | 功能描述:直流/直流开关转换器 Quad-Output TFT LCD w/Buffer 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 |
| MAX1778EUG-T | 功能描述:直流/直流开关转换器 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 |
| MAX1778EVKIT | 功能描述:电源管理IC开发工具 MAX1778/80/81/82 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 |
| MAX1779EUE | 功能描述:直流/直流开关转换器 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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