参数资料
| 型号： | LTC3617EUDD#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 16/20页 |
| 文件大小： | 0K |
| 描述： | IC REG SYNC 6A BUCK 24QFN |
| 标准包装： | 2,500 |
| 应用： | 转换器，DDR，DDR2，DDR3 |
| 输入电压： | 2.25 V ~ 5.5 V |
| 输出数： | 1 |
| 输出电压： | 可调至 0.5V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-WFQFN 裸露焊盘 |
| 供应商设备封装： | 24-QFN（3x5） |
| 包装： | 带卷 (TR) |
LTC3617
APPLICATIONS INFORMATION
I RMS = 6A ?
– 1 ? = 3A RMS
? ?
R T =
3.82 11 Hz
– 16k = 130k ?
L = ?
? ? ? ? ? 1– 2.5V ? ? = 0.12μH
Remembering that the above junction temperature is
obtained from the R DS(ON) at 25°C, we might recalculate
the junction temperature based on a higher R DS(ON) since
it increases with temperature. Redoing the calculation
assuming that R SW increased 15% at 73°C yields a new
junction temperature of 79°C. Therefore, we can safely as -
sume that the actual junction temperature will not exceed
the absolute maximum junction temperature of 125°C.
Note that for very low input voltage, the junction tempera -
ture will be higher due to increased switch resistance,
R DS(ON) . It is not recommended to use full load current
with high ambient temperature and low input voltage.
To maximize the thermal performance of the LTC3617 the
exposed pad must be soldered to a ground plane. See the
PCB Layout Board Checklist.
Design Example
As a design example, consider the LTC3617 in an applica-
tion with the following specifications:
V IN = 2.5V, V OUT = 1.25V, I OUT(MAX) = 6A, I OUT(MIN) =
200mA, f = 2.6MHz.
First, calculate the timing resistor:
2.6MHz
Next, calculate the inductor value for about 33% ripple
current at maximum V IN :
? 1.25V ? ? 1.25V ?
? 2.6MHz ? 2A
Using a standard value of 0.1μH inductor results in a
maximum ripple current of:
C IN should be selected for a maximum current rating of:
1.25V ? 2.5V ?
2.5V ? 1.25V ?
Decoupling PV IN with four 10μF to 22μF capacitors is
adequate for most applications. Connecting the V FB pin
directly to V OUT will set the output voltage equal to one-half
of the voltage on the VDDQIN pin. The complete circuit of
this design example is illustrated in Figure 1.
PC Board Layout Checklist
When laying out the printed circuit board, the following
checklist should be used to ensure proper operation of
the LTC3617:
1. A ground plane is recommended. If a ground plane layer
is not used, the signal and power grounds should be
segregated with all small-signal components returning
to the SGND pin at one point which is then connected
to the PGND pin close to the LTC3617.
2. Connect the (+) terminal of the input capacitor(s), C IN ,
as close as possible to the PV IN pin, and the (–) terminal
as close as possible to the exposed pad, PGND. This
capacitor provides the AC current into the internal power
MOSFETs.
3. Keep the switching node, SW, away from all sensitive
small-signal nodes.
4. Flood all unused areas on all layers with copper. Flood -
ing with copper will reduce the temperature rise of
power components. Connect the copper areas to PGND
(exposed pad) for best performance.
5. Connect the V FB pin directly to V OUT .
? I L = ?
? ? ? ? ? 1– 2.5V ? ? = 2.4A
? 1.25V
? 2.6MHz ? 0.1μH
? ? 1.25V ?
C OUT will be selected based on the ESR that is required
to satisfy the output voltage ripple requirement and the
bulk capacitance needed for loop stability. For this design,
a 100μF ceramic capacitor is used with a X5R or X7R
dielectric.
3617fa
16
相关PDF资料 |
PDF描述 |
|---|---|
| HBC35DRES-S93 | CONN EDGECARD 70POS .100 EYELET |
| HMM08DRKF-S13 | CONN EDGECARD 16POS .156 EXTEND |
| HBM36DRKS | CONN EDGECARD 72POS DIP .156 SLD |
| GSC30DRYS-S93 | CONN EDGECARD 60POS DIP .100 SLD |
| GCM40DTBT | CONN EDGECARD 80POS R/A .156 SLD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| PIC18LF4620T-I/ML | 功能描述:8位微控制器 -MCU 64KB 3968 RAM 36I/O RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| PIC18LF4620T-I/PT | 功能描述:8位微控制器 -MCU 64KB 3968 RAM 36I/O RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| PIC18LF4680-I/ML | 功能描述:8位微控制器 -MCU 64KB 3328 RAM w/ECAN RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| PIC18LF4680-I/P | 功能描述:8位微控制器 -MCU 64KB 3328 RAM w/ECAN RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| PIC18LF4680-I/P | 制造商:Microchip Technology Inc 功能描述:8-Bit Microcontroller IC |
发布紧急采购，3分钟左右您将得到回复。