- 您现在的位置：买卖IC网 > PDF目录13813 > A8483EEKTR-T (Allegro Microsystems Inc)IC REG BOOST ADJ 0.35A 5MLP PDF资料下载
参数资料
| 型号： | A8483EEKTR-T |
| 厂商： | Allegro Microsystems Inc |
| 文件页数： | 5/10页 |
| 文件大小： | 0K |
| 描述： | IC REG BOOST ADJ 0.35A 5MLP |
| 标准包装： | 1 |
| 类型： | 升压（升压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 可调至 35V |
| 输入电压： | 2.5 V ~ 10 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 1.2MHz |
| 电流 - 输出： | 350mA |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 5-WDFN 裸露焊盘 |
| 包装： | 剪切带 (CT) |
| 供应商设备封装： | 5-MLP/TDFN（3x3） |
| 其它名称： | 620-1101-1 |
A8483
1.2 MHz Step-up Converter
for Display Bias Supply
Functional Description
Pin Functions
VIN. Supply to the control circuit. A bypass capacitor, C1, must
be connected from close to this pin to GND.
GND. Ground reference connected directly to the ground plane.
A typical WLED backlight supply is shown in figure 8. The load
current, I LOAD , is set by the selecting the external sense resistor,
R1, to produce 615 mV at the desired load, for example:
The feedback resistor should have a separate connection directly
to this point.
EN. Voltage lower than 0.4 V disables the A8483 and puts the
R 1 = 0.615 I LOAD .
(2)
control circuit into the low-power sleep mode. Voltage greater
than 1.5 V fully enables the A8483.
SW. Low-side switch connection between the inductor, L1, and
ground. Because rapid changes of current occur at this pin, the
traces on the PCB that are connected to this pin should be mini-
mized. In addition, L1 and the diode, D1, should be connected as
close to this pin as possible.
FB. Feedback pin for OLED voltage control or WLED current
control. The reference voltage is 615 mV. Connect the feedback
resistor close to this pin to minimize noise.
Device Operation
The A8483 uses a 1.2 MHz constant switching frequency current-
mode control scheme to regulate the output voltage or current
through the load.
A typical OLED bias supply is shown in figure 7. For driving
OLEDs, output voltage is sensed by the FB pin through a voltage
divider network. Output voltage, V OUT (V), is set according to the
following equation:
Voltage sensed across the FB pin is compared with the internal
615 mV reference to produce an error signal. The switch cur-
rent is sensed by the internal sense resistor and compared to the
error signal for current mode PWM control. As the error signal
increases, I LOAD , increases to increase either output voltage,
V OUT , or current, I OUT , such that the FB pin voltage follows the
internal 615 mV reference voltage.
As I LOAD is reduced, the energy required in the inductor, L1, also
reduces, resulting in the inductor current dropping to zero for low
load current levels. This is known as Discontinuous mode opera-
tion and results in some low-frequency ripple. The average load
current will, however, remain regulated down to zero. In Discon-
tinuous mode, when I LOAD drops to zero, the voltage at the SW
pin rings, due to the resonant LC circuit formed by L1 and the
switch and diode D1 capacitance. This ringing is low-frequency
V OUT =
R 1 + R 2
R 2
0.615 .
(1)
and is not harmful. It can be damped with a resistor across the
inductor but this will reduce efficiency and is not recommended.
V OUT
V OUT
5
L1
10 μH
1
D1
5
L1
10 μH
1
D1
VIN
SW
VIN
SW
V SUPPLY
C1
1 μF
EN
A8483
GND
FB
R1
820 k Ω
C2
1 μ μF
V SUPPLY
C1
1 μF
EN
A8483
GND
FB
R3
24 k Ω
C2
0.22 μF
V C
Li-ion
2.5 V to
5.5 V
4
Enable
2
3
R2
39 k Ω
Li-ion
2.5 V to
5.5 V
4
Enable
2
3
Cf
0.01 μF
R2
5 k Ω
R1
47 Ω
Analog Voltage or
PWM
Figure 7. OLED Bias Supply. Use for cell phones, MP3 players, DSCs,
and PDAs. (Circuit also shown in figure 1.)
Figure 8. WLED Backlighting. (Circuit also shown in figure 5.)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
相关PDF资料 |
PDF描述 |
|---|---|
| EBC31DREH-S734 | CONN EDGECARD 62POS .100 EYELET |
| ABC05DRTN-S734 | CONN EDGECARD 10POS DIP .100 SLD |
| ABC05DRTH-S734 | CONN EDGECARD 10POS DIP .100 SLD |
| GBC40DCST-S288 | CONN EDGECARD 80POS .100 EXTEND |
| EBC40DCMT-S288 | CONN EDGECARD 80POS .100 EXTEND |
相关代理商/技术参数 |
参数描述 |
|---|---|
| A84856-000 | 制造商:TE Connectivity 功能描述:Conn Power 制造商:TE Connectivity 功能描述:MTCPQKT1P2SGDC |
| A848KBH | 制造商:TE Connectivity / Hartman Brand 功能描述: |
| A848KH | 功能描述:A848KH (FAA/PMA)=RELAY 制造商:te connectivity aerospace, defense and marine 系列:* 零件状态:有效 标准包装:1 |
| A-848KK | 制造商:MA-COM 制造商全称:M/A-COM Technology Solutions, Inc. 功能描述:A-848KK 2PST N.O., 75 Amps, 28 VDC |
| A848KK1 | 功能描述:通用继电器 CONTACTOR-DPST N.O. LOAD CURRENT RoHS:否 制造商:Omron Electronics 触点形式:1 Form A (SPST-NO) 触点电流额定值:150 A 线圈电压:24 VDC 线圈电阻:144 Ohms 线圈电流:167 mA 切换电压:400 V 安装风格:Chassis 触点材料: |
发布紧急采购，3分钟左右您将得到回复。