- 您现在的位置：买卖IC网 > PDF目录15296 > LTC3838EUHF#TRPBF (Linear Technology)IC REG CTRLR BUCK PWM CM 38-QFN PDF资料下载
参数资料
| 型号： | LTC3838EUHF#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 41/54页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 38-QFN |
| 标准包装： | 2,500 |
| 系列： | PolyPhase® |
| PWM 型： | 电流模式 |
| 输出数： | 2 |
| 频率 - 最大： | 2MHz |
| 电源电压： | 4.5 V ~ 38 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 38-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页当前第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页
LTC3838
APPLICATIONS INFORMATION
These numbers show that careful attention should be paid
to proper heat sinking when operating at higher ambient
temperatures.
Select the C IN capacitors to give ample capacitance and
RMS ripple current rating. Consider worst-case duty cycles
per Figure 6: If operated at steady-state with SW nodes
fully interleaved, the two channels would generate not
more than 7.5A RMS at full load. In this design example,
3 × 10μF 35V X5R ceramic capacitors are put in parallel
to take the RMS ripple current, with a 220μF aluminum-
electrolytic bulk capacitor for stability. For 10μF 1210 X5R
ceramic capacitors, try to keep the ripple current less
than 3A RMS through each device. The bulk capacitor
is chosen for RMS rating per simulation with the circuit
model provided.
The output capacitor C OUT is chosen for a low ESR of
4.5mΩ to minimize output voltage changes due to inductor
ripple current and load steps. The output voltage ripple
is given as:
? V OUT(RIPPLE) = ? I L(MAX) ? ESR = 5.85A ? 4.5mΩ = 26mV
However, a 10A load step will cause an output change of
up to:
? V OUT(STEP) = ? I LOAD ? ESR = 10A ? 4.5mΩ = 45mV
Optional 2 × 100μF ceramic output capacitors are included
to minimize the effect of ESR and ESL in the output ripple
and to improve load step response.
The ITH compensation resistor R ITH of 40k and a C ITH of
220pF are chosen empirically for fast transient response,
and an additional C ITH2 = 22pF is added directly from
ITH pin to SGND, to roll off the system gain at switching
frequency and attenuate high frequency noise.
To set up the detect transient (DTR) feature, pick resistors
for an equivalent R ITH = R ITH1 //R ITH2 close to the 40k.
Here, 1% resistors R ITH1 = 90.9k (low side) and R ITH2
= 82.5k (high side) are used, which yields an equivalent
one-half of INTV CC . Note that even though the accuracy
of the equivalent compensation resistance R ITH is not as
important, always use 1% or better resistors for the resis-
tor divider from INTV CC to SGND to guarantee the relative
accuracy of this DC-bias threshold. To disable the DTR
feature, simply use a single R ITH resistor to SGND, and
tie the DTR pin to INTV CC .
PCB Layout Checklist
The printed circuit board layout is illustrated graphically
in Figure 14. Figure 15 illustrates the current waveforms
present in the various branches of 2-phase synchronous
regulators operating in continuous mode. Use the follow-
ing checklist to ensure proper operation of the LTC3838:
? A multilayer printed circuit board with dedicated ground
planes is generally preferred to reduce noise coupling
and improve heat sinking. The ground plane layer
should be immediately next to the routing layer for the
power components, e.g., MOSFETs, inductors, sense
resistors, input and output capacitors etc.
? Keep SGND and PGND separate. Upon finishing the
layout, connect SGND and PGND together with a single
PCB trace underneath the IC from the SGND pin through
the exposed PGND pad to the PGND pin.
? All power train components should be referenced to
PGND; all components connected to noise-sensitive
pins, e.g., ITH, RT , TRACK/SS and V RNG , should return
to the SGND pin. Keep PGND ample, but SGND area
compact. Use a modified “star ground” technique: a low
impedance, large copper area central PCB point on the
same side of the as the input and output capacitors.
? Place power components, such as C IN , C OUT , MOSFETs,
D B and inductors, in one compact area. Use wide but
shortest possible traces for high current paths (e.g.,
V IN , V OUT , PGND etc.) to this area to minimize copper
loss.
R ITH of 43.2k, and a DC-bias threshold of 128mV above
3838fa
41
相关PDF资料 |
PDF描述 |
|---|---|
| LTC3856EUH#TRPBF | IC REG CTRLR BUCK PWM CM 38-QFN |
| SXR222M010ST | CAP ALUM 2200UF 10V 20% RADIAL |
| LTC3855EUJ#TRPBF | IC REG CTRLR BUCK PWM CM 40-QFN |
| UCY2C121MHD | CAP ALUM 120UF 160V 20% RADIAL |
| LT1950IGN | IC REG CTRLR PWM CM 16-SSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3838IFE#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 38TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC3838IFE#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 38TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC3838IUHF#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 38-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3838IUHF#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 38-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3838IUHF-1#PBF | 制造商:Linear Technology 功能描述:IC REG CTRLR BUCK PWM CM 38QFN 制造商:Linear Technology 功能描述:BUCK DUAL CNTRL 4.5-38V 2MHZ 38QFN 制造商:Linear Technology 功能描述:BUCK, DUAL, CNTRL, 4.5-38V, 2MHZ, 38QFN 制造商:Linear Technology 功能描述:DP-SWREG/Controller, Dual, Fast, Accurate Step-Down Controller with Differential 制造商:Linear Technology 功能描述:DC-DC CONTROLLER, DUAL, BUCK, ADJ, QFN-38, Primary Input Voltage:38V, No. of Outputs:2, Output Current:25A, No. of Pins:38, Operating Temperature Min:-40C, Operating Temperature Max:125C, MSL:MSL 1 - Unlimited , RoHS Compliant: Yes |
发布紧急采购，3分钟左右您将得到回复。