- 您现在的位置：买卖IC网 > PDF目录20846 > LT3476IUHF#PBF (Linear Technology)IC LED DRVR HP CONST CURR 38QFN PDF资料下载
参数资料
| 型号： | LT3476IUHF#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 8/14页 |
| 文件大小： | 0K |
| 描述： | IC LED DRVR HP CONST CURR 38QFN |
| 标准包装： | 52 |
| 恒定电流： | 是 |
| 拓扑： | PWM，降压（降压），升压（升压） |
| 输出数： | 4 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 车载，背光 |
| 类型 - 次要： | 颜色，RGB |
| 频率： | 200kHz ~ 2MHz |
| 电源电压： | 2.8 V ~ 16 V |
| 输出电压： | 2.2 V ~ 36 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 38-WFQFN 裸露焊盘 |
| 供应商设备封装： | 38-QFN（5x7） |
| 包装： | 管件 |
| 工作温度： | -40°C ~ 85°C |
LT3476
APPLICATIONS INFORMATION
L( μ H) = BUCK
D ? T SW ( μ S) ? (V CAP ? V LED )
D BUCK =
D BOOST ? T SW ( μ S) ? V IN
? I
= CAP
V ? V IN
D BOOST
C FILT = 2 ?
switch,thestateofthePWMpinissampledonlyduring
a narrow time slot at the beginning of each switch period.
Inductor Selection
The inductors used with the LT3476 should have a satura-
tion current rating of 2.5A or greater. For best loop stability
results, the inductor value selected should provide a ripple
current of 350mA or more. For buck (step-down) or boost
(step-up) configurations, and using a 21kΩ resistor on
R T (T SW ~ 1μs), inductor values from 4.7μH to 10μH are
recommended for most applications. In the buck mode,
the inductor value can be estimated using the formula:
,
? I
V LED
V CAP
V LED is the voltage across the LED string and V CAP is the
input voltage to the converter. In the boost mode, the
inductor value can be estimated using the formula:
L( μ H) = ,
V CAP
V IN is the input voltage and V CAP is the voltage across
the LED string. Table 2 below provides some suggested
components and vendors.
Table 2. Inductor s
VALUE IRMS DCR HEIGHT
PART NUMBER (μH) (A) (Ω) (mm)
Sumida
CDRH6D38-100 10 2.0 0.028 4.0
CDRH5D28-5R3 5.3 1.90 0.028 3.0
CDRH73-100 10 1.68 0.072 3.4
Toko
D63CB 10 1.49 0.042 3.5
D63CB 4.7 2.08 0.026 3.5
Cooper-ET
SD25-4R7 4.7 1.80 0.047 2.5
Input Capacitor Selection
For proper operation, it is necessary to place a bypass
capacitor to GND close to the V IN pin of the LT3476. A
1μF, or greater, capacitor with low ESR should be used.
A ceramic capacitor is usually the best choice.
In the buck configuration, the capacitor at the input to the
power converter has large pulsed currents due to the cur-
rent returned through the Schottky diode when the switch
is off. For best reliability, this capacitor should have low
ESR and ESL and meet the ripple current requirement,
I RMS = I SW ? ( (1 ? D) ? D )
where D is the switch duty cycle. A 2.2μF ceramic type
capacitor placed close to the Schottky and the ground
plane is usually sufficient for each channel.
Output Capacitor Selection
The selection of output filter capacitor depends on the load
and the converter configuration, i.e., step-up or step-down.
For LED applications, the equivalent resistance of the LED
is typically low, and the output filter capacitor should be
sized to attenuate the current ripple from the inductor to
35mA or less. The following equation is useful to estimate
the required capacitor value:
T SW
R LED
A typical filter capacitor value for R LED = 5Ω and T SW =
1μs is 0.47μF. For loop stability, consider the output pole
is at the frequency where closed loop gain should be
unity, so the dominant pole for loop compensation will
be established by the capacitor at the V C input.
For the LED boost applications, to achieve the same LED
ripple current the required filter capacitor value is about
five times larger than the value calculated above due to
the pulsed nature of the source current. A 2.2μF ceramic
type capacitor placed close to the Schottky and the ground
plane of the I C is usually sufficient for each channel.
As the output capacitor is subject to high ripple current,
ceramic capacitors are recommended due to their low
ESR and ESL at high frequency.
3476fb
8
相关PDF资料 |
PDF描述 |
|---|---|
| P51-1000-S-AA-MD-4.5V-000-000 | SENSOR 1000PSI 7/16-20 UNF 4.5V |
| P51-1000-S-B-P-4.5OVP-000-000 | SENSOR 1000PSI 1/8-27NPT .5-4.5V |
| REC5-1212SRW/H2/C/M/SMD-R | CONV DC/DC 5W 9-18VIN 12VOUT |
| P51-3000-S-Z-MD-4.5V-000-000 | SENSOR 3000PSI 1/4-18NPT .5-4.5V |
| TMS-WINTOTAL-SWARE-DGLUSB | SOFTWARE - WIREMARKER PRINTING |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3477 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Full-Featured LED Driver with 1.5A Switch Current |
| LT3477EFE | 制造商:Linear Technology 功能描述:LED DRVR 4Segment 3.3V/5V/9V/12V/15V/18V/24V 20-Pin TSSOP EP |
| LT3477EFE#PBF | 功能描述:IC LED DRVR HP CONS CURR 20TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:60 系列:- 恒定电流:- 恒定电压:- 拓扑:线性（LDO），PWM，升压（升压） 输出数:8 内部驱动器:是 类型 - 主要:背光 类型 - 次要:RGB，白色 LED 频率:500kHz ~ 1.5MHz 电源电压:4.75 V ~ 26 V 输出电压:45V 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:* 工作温度:-40°C ~ 85°C |
| LT3477EFE#TR | 制造商:Linear Technology 功能描述:LED DRVR 4Segment 3.3V/5V/9V/12V/15V/18V/24V 20-Pin TSSOP EP T/R |
| LT3477EFE#TRPBF | 功能描述:IC LED DRVR HP CONS CURR 20TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极，PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
发布紧急采购，3分钟左右您将得到回复。