- 您现在的位置：买卖IC网 > PDF目录16560 > MAX749ESA+T (Maxim Integrated Products)IC SUPPLY LCD BIAS ADJ 8-SOIC PDF资料下载
参数资料
| 型号： | MAX749ESA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 10/12页 |
| 文件大小： | 0K |
| 描述： | IC SUPPLY LCD BIAS ADJ 8-SOIC |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 应用： | LCD 显示器 |
| 电流 - 电源： | 60µA |
| 电源电压： | 2 V ~ 6 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 8-SOIC |
| 包装： | 带卷 (TR) |
Digitally Adjustable LCD Bias Supply
The Sumida CD54-470N (47μH, 720mA, 370m ? ) is suit-
Table 2. Component Suppliers
able for a wide range of applications, and the larger
CD105-470N (47μH, 1.17A, 170m ? ) permits higher cur-
rent levels and efficiencies.
Diode Selection
The MAX749’s high switching frequency demands a high-
speed rectifier. Schottky diodes such as the 1N5817-
1N5822 family are recommended. Choose a diode with an
average current rating approximately equal to the peak
current, as determined by 180mV/R SENSE and a break-
down voltage greater than V+ + I -V OUTMAX I .
External Switching Transistor
The MAX749 can drive a PNP transistor or a P-channel
logic-level MOSFET. The choice of a power switch is
dictated by the input voltage range, cost, and efficiency.
MOSFETs provide the highest efficiency because they
do not draw any DC gate-drive current (see Typical
Operating Characteristics graphs). However, a gate-
source voltage of several volts is needed to turn on a
MOSFET, so a 5V or greater input supply is required
(although this restriction may change as lower-thresh-
old P-channel MOSFETs become available). PNP tran-
sistors, meanwhile, may be used over the entire 2V to
SUPPLIER
INDUCTORS
Coiltronics
Gowanda
Sumida USA
Sumida Japan
CAPACITORS
Kemet
Matsuo
Nichicon
Sprague
Sanyo USA
Sanyo Japan
United Chemi-Con
DIODES
Motorola
Nihon USA
Nihon Japan
PHONE
(305) 781-8900
(716) 532-2234
(708) 956-0666
81-3-3607-511
(803) 963-6300
(714) 969-2491
(708) 843-7500
(603) 224-1961
(619) 661-6322
81-3-3837-6242
(714) 255-9500
(800) 521-6274
(805) 867-2555
81-3-3494-7411
FAX
(305) 782-4163
(716) 532-2702
(708) 956-0702
81-3-3607-5428
(803) 963-6322
(714) 960-6492
(708) 843-2798
(603) 224-1430
(714) 255-9400
(805) 867-2698
81-3-3494-7414
6V operating voltage range of the MAX749.
POWER TRANSISTORS - MOSFETS
When using a MOSFET, connect DHI and DLOW to its
gate (see Typical Operating Circuit). When using a PNP
Harris
(407) 724-3739
(407) 724-3937
transistor, connect DHI to its base, and connect a resis-
tor between the base and DLOW (R BASE ) (Figure 1). The
PNP transistor is turned off quickly by the direct pull-up
of DHI, and turned on by the base current provided
through R BASE . This resistor limits the transistor’s base-
drive current to (V IN - 140mV - V BE )/R BASE , where V IN is
the input voltage, 140mV is the drop across R SENSE , V BE
is the transistor’s base-emitter voltage, and R BASE is the
current-limiting resistor. For maximum efficiency, make
R BASE as large as possible, but small enough so that the
transistor is always driven into saturation.
Highest efficiency with a PNP transistor comes from
using a device with a low collector-emitter saturation
voltage and a high current gain. Use a fast-switching
type. For example the Zetex ZTX792A has switching
speeds of 40ns (t ON ) and 500ns (t OFF ).
The transistor must have a collector-to-emitter (PNP) or
drain-to-source (MOSFET) voltage rating greater than the
input-to-output voltage differential (V IN - V OUT ). In either
case the transistor must have a current rating that exceeds
the peak current set by the current-sense resistor.
PNP transistors are generally less expensive than P-
channel MOSFETs. Table 2 lists some suppliers of
switching transistors suitable for use with the MAX749.
International
(213) 772-2000 (213) 772-9028
Rectifier
Siliconix (408) 988-8000 (408) 727-5414
POWER TRANSISTORS - PNP TRANSISTORS
Zetex USA (516) 543-7100 (516) 864-7630
Zetex UK 44 (61) 727 5105 44 (61) 627 5467
CURRENT-SENSE RESISTORS
IRC (512) 992-7900 (512) 992-3377
Base Resistor
The base resistor, R BASE in Figure 1, controls the amount of
base current in the PNP transistor. A low value for R BASE
increases base drive, which provides higher output cur-
rents and compensates for lower input voltages, but
decreases efficiency. Conversely, a high R BASE value
increases efficiency but reduces the output capability,
especially at low voltages. When using high-gain transis-
tors, e.g. the Zetex ZTX750 or ZTX792, typical values for
R BASE are in the 150 ? to 510 ? range, but will depend on
the required input voltage range and output current (see
Typical Operating Characteristics). Lower-gain transistors
require lower values for R BASE and are less efficient. Larger
R BASE values are suitable if less output power is required.
10
_____________________________________________________________________________________
相关PDF资料 |
PDF描述 |
|---|---|
| RSA06DRSN-S288 | CONN EDGECARD 12POS .125 EXTEND |
| H3CCS-6406M | IDC CABLE - HKC64S/AE64M/HKC64S |
| UPC3218GV-EVAL | EVAL BOARD FOR UPC3218GV |
| M2MXH-2020K | IDC CABLE - MDM20H/MC20F/X |
| GBC19DRES-S734 | CONN EDGECARD 38POS .100 EYELET |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX749ESA-TG074 | 制造商:Maxim Integrated Products 功能描述:DIGITALLY ADJUSTABLE LCD BIAS SUPPLY - Rail/Tube |
| MAX749EVKIT-SO | 功能描述:显示开发工具 RoHS:否 制造商:4D Systems 产品:4Display Shields 工具用于评估:?OLED-160-G1, ?OLED-160-G2 接口类型:Serial 工作电源电压:5 V |
| MAX-750 | 制造商:SLPOWER 制造商全称:SL Power Electronics 功能描述:MAX-750 Multiple Output |
| MAX7500EVKIT+ | 功能描述:板上安装温度传感器 MAX7500 Eval Kit RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor |
| MAX7500MSA | 功能描述:板上安装温度传感器 RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor |
发布紧急采购，3分钟左右您将得到回复。