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参数资料
| 型号： | MAX8631XETI+ |
| 厂商： | Maxim Integrated |
| 文件页数： | 10/15页 |
| 文件大小： | 0K |
| 描述： | IC LED DRVR WHITE BCKLGT 28-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 75 |
| 恒定电流： | 是 |
| 拓扑： | 线性（LDO），切换式电容器（充电泵） |
| 输出数： | 8 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 背光，闪灯/白光 |
| 类型 - 次要： | 白色 LED |
| 频率： | 1MHz |
| 电源电压： | 2.7 V ~ 5.5 V |
| 输出电压： | 5V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-TQFN-EP（4x4） |
| 包装： | 管件 |
| 工作温度： | -40°C ~ 85°C |
1x/1.5x/2x White LED Charge Pump with Two
LDOs in 4mm x 4mm Thin QFN
Pin Description (continued)
PIN
23
24
25
26
27
28
—
NAME
C1P
PGND
OUT
C2P
C2N
P1
EP
FUNCTION
Transfer Capacitor 1 Positive Connection. Connect a 1μF ceramic capacitor between C1P to C1N.
During shutdown, if OUT > IN, C1P is shorted to OUT. If OUT < IN, C1P is shorted to IN.
Power Ground. Connect PGND to system ground. PGND is used for charge-pump switching currents.
Charge-Pump Output. Bypass OUT to GND with a 10μF ceramic capacitor. Connect to the anodes of
all the LEDs. OUT is internally pulled to ground through a 5k Ω resistor during shutdown.
Transfer Capacitor 2 Positive Connection. Connect a 1μF ceramic capacitor between C2P to C2N.
During shutdown, if OUT > IN, C2P is shorted to OUT. If OUT < IN, C2P is shorted to IN.
Transfer Capacitor 2 Negative Connection. Connect a 1μF ceramic capacitor between C2P and C2N.
C2N is internally shorted to IN during shutdown.
Default Output-Voltage Select Input. P1 and P2 set the LDO1 and LDO2 voltages to one of nine
combinations (Table 2). P1 is high impedance in an off condition and shortly after an on condition.
Exposed Paddle. Connect to GND and PGND.
Detailed Description
The MAX8631X/Y charge pump drives up to 4 white
LEDs in the main display for backlighting and up to 4
white LEDs for flash, all with regulated constant current
for uniform intensity. By utilizing adaptive 1x/1.5x/2x
charge-pump modes and very-low-dropout current reg-
ulators, it achieves high efficiency over the 1-cell lithi-
um-battery input voltage range. 1MHz fixed-frequency
switching allows for tiny external components and low
input ripple. Two on-board 200mA programmable-out-
put-voltage LDOs are provided to meet camera-module
requirements.
1x to 1.5x Switchover
When V IN is higher than V OUT , the MAX8631X/Y oper-
ates in 1x mode and V OUT is pulled up to V IN . The
internal current regulators regulate the LED current. As
V IN drops, V M_ (or V F_ ) eventually falls below the
switchover threshold of 100mV and the MAX8631X/Y
starts switching in 1.5x mode. When the input voltage
rises above V OUT by approximately 50mV, the
MAX8631X/Y switches back to 1x mode.
1.5x to 2x Switchover
When V IN is less than V OUT but greater than two-thirds
V OUT , the MAX8631X/Y operates in 1.5x mode. The
internal current regulators regulate the LED current. As
V IN drops, V M_ (or V F_ ) eventually falls below the
switchover threshold of 100mV, and the MAX8631X/Y
starts switching in 2x mode. When the input voltage
rises above two-thirds V OUT by approximately 50mV,
the MAX8631X/Y switches back to 1.5x mode.
True Shutdown is a trademark of Maxim Integrated Products, Inc.
Soft-Start
The MAX8631X/Y includes soft-start circuitry to limit
inrush current at turn-on. Once the input voltage is
applied, the output capacitor is charged directly from
the input with a ramped current source (with no charge-
pump action) until the output voltage approaches the
input voltage. Once the output capacitor is charged,
the charge pump determines if 1x, 1.5x, or 2x mode is
required. In the case of 1x mode, the soft-start is termi-
nated and normal operation begins. In the case of 1.5x
or 2x mode, soft-start operates until the lowest voltage
of M1–M4 and F1–F4 reaches regulation. If the output is
shorted to ground or is pulled to less than 1.25V, the
output current is limited by soft-start.
True Shutdown? Mode
When ENM1, ENM2, and ENF are simultaneously held
low for 2.5ms or longer, the MAX8631X/Y is shut down
and put in a low-current shutdown mode, and the input
is isolated from the output. OUT is internally pulled to
GND with 5k Ω during shutdown.
Thermal Derating
The MAX8631X/Y limits the maximum LED current
depending on the die temperature. The maximum LED
current is set by the R SETM and R SETF resistors. Once
the temperature reaches +43°C, the LED current
decreases by 1.7%/°C. Due to the package’s exposed
paddle, the die temperature is always very close to the
PC board temperature.
The temperature derating function allows the LED cur-
rent to be safely set higher at normal operating temper-
atures, thereby allowing either a brighter display or
fewer LEDs to be used for normal display brightness.
10
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8631XETI+ | 功能描述:电荷泵 1x/1.5x/2x White LED Charge Pump RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 输出电压:- 1.5 V to - 5.5 V, 3 V to 11 V 输出电流:100 mA 电源电流:1 mA 最大工作温度:+ 70 C 封装 / 箱体:SOIC-8 Narrow 封装:Tube |
| MAX8631XETI+G104 | 制造商:Maxim Integrated Products 功能描述:1X/1.5X/2X WHITE LED CHARGE PUMP WI - Rail/Tube |
| MAX8631XETI+T | 功能描述:LED照明驱动器 1x/1.5x/2x White LED Charge Pump RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N |
| MAX8631XETI+TG104 | 制造商:Maxim Integrated Products 功能描述:1X/1.5X/2X WHITE LED CHARGE PUMP WI - Tape and Reel |
| MAX8631XETI+TW | 制造商:Maxim Integrated Products 功能描述:CHG PUMP STPUP 5V 580MA 28TQFN EP - Tape and Reel |
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