- 您现在的位置：买卖IC网 > PDF目录13071 > LTC3714EG#TR (Linear Technology)IC STP-DWN CNTRLR W/OPAMP 28SSOP PDF资料下载
参数资料
| 型号： | LTC3714EG#TR |
| 厂商： | Linear Technology |
| 文件页数： | 12/28页 |
| 文件大小： | 0K |
| 描述： | IC STP-DWN CNTRLR W/OPAMP 28SSOP |
| 标准包装： | 2,000 |
| 应用： | 控制器，Intel Pentium? |
| 输入电压： | 4 V ~ 36 V |
| 输出数： | 1 |
| 输出电压： | 0.6 V ~ 1.75 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-SSOP（0.209"，5.30mm 宽） |
| 供应商设备封装： | 28-SSOP |
| 包装： | 带卷 (TR) |
| 其它名称： | LTC3714EGTR |
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页当前第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
LTC3714
APPLICATIONS INFORMATION
R SENSE =
R DS(ON)(MAX) =
D TOP =
V – V OUT
The basic LTC3714 application circuit is shown in
Figure 1. External component selection is primarily de-
termined by the maximum load current and begins with
the selection of the sense resistance and power MOSFET
switches. The LTC3714 can use either a sense resistor or
the on-resistance of the synchronous power MOSFET for
determining the inductor current. The desired amount of
ripple current and operating frequency largely determines
the inductor value. Finally, C IN is selected for its ability to
handle the large RMS current into the converter and C OUT
is chosen with low enough ESR to meet the output voltage
ripple and transient specification.
Maximum Sense Voltage and V RNG Pin
Inductor current is determined by measuring the volt-
age across a sense resistance that appears between the
PGND and SENSE pins. The maximum sense voltage is
set by the voltage applied to the V RNG pin and is equal
to approximately (0.133)V RNG . The current mode control
loop will not allow the inductor current valleys to exceed
(0.133)V RNG /R SENSE . In practice, one should allow some
margin for variations in the LTC3714 and external com-
ponent values and a good guide for selecting the sense
resistance is:
V RNG
10 ? I OUT(MAX)
An external resistive divider from INTV CC can be used
to set the voltage of the V RNG pin between 0.5V and 2V
resulting in nominal sense voltages of 50mV to 200mV.
Additionally, the V RNG pin can be tied to SGND or INTV CC in
which case the nominal sense voltage defaults to 70mV or
140mV, respectively. The maximum allowed sense voltage
is about 1.33 times this nominal value.
Connecting the SENSE Pin
The LTC3714 can be used with or without a sense resis-
tor. When using a sense resistor, it is placed between the
source of the bottom MOSFET M2 and ground. Connect
the SENSE pin to the source of the bottom MOSFET so
that the resistor appears between the SENSE and PGND
pins. Using a sense resistor provides a well defined cur-
rent limit, but adds cost and reduces efficiency. Alterna-
tively, one can eliminate the sense resistor and use the
12
bottom MOSFET as the current sense element by simply
connecting the SENSE pin to the switch node SW at the
drain of the bottom MOSFET. This improves efficiency, but
one must carefully choose the MOSFET on-resistance as
discussed below.
Power MOSFET Selection
The LTC3714 requires two external N-channel power
MOSFETs, one for the top (main) switch and one for the
bottom (synchronous) switch. Important parameters for
the power MOSFETs are the breakdown voltage V (BR)DSS ,
threshold voltage V (GS)TH , on-resistance R DS(ON) , reverse
transfer capacitance C RSS and maximum current I DS(MAX) .
The gate drive voltage is set by the 5V INTV CC supply.
Consequently, logic-level threshold MOSFETs must be used
in LTC3714 applications. If the input voltage is expected
to drop below 5V, then sub-logic level threshold MOSFETs
should be considered.
When the bottom MOSFET is used as the current sense
element, particular attention must be paid to its on-
resistance. MOSFET on-resistance is typically specified
with a maximum value R DS(ON)(MAX) at 25°C. In this case,
additional margin is required to accommodate the rise in
MOSFET on-resistance with temperature:
R SENSE
ρ T
The ρ T term is a normalization factor (unity at 25°C)
accounting for the significant variation in on-resistance
with temperature, typically about 0.4%/°C as shown in
Figure 3. Junction-to-case temperature is about 30°C in
most applications. For a maximum ambient temperature
of 70°C, using a value ρ 100°C = 1.3 is reasonable.
The power dissipated by the top and bottom MOSFETs
strongly depends upon their respective duty cycles and the
load current. When the LTC3714 is operating in continuous
mode, the duty cycles for the MOSFETs are:
V OUT
V IN
D BOT = IN
V IN
3714f
相关PDF资料 |
PDF描述 |
|---|---|
| RBC22DREN-S93 | CONN EDGECARD 44POS .100 EYELET |
| C1005X7R1H102M | CAP CER 1000PF 50V 20% X7R 0402 |
| AHA336M35D16T-F | CAP ALUM 33UF 35V 20% SMD |
| EBA50DTBZ-S664 | CONN EDGECARD 100PS R/A .125 SLD |
| MIC5239YMM | IC REG LDO ADJ .5A 8MSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3716EG | 功能描述:IC REG CTRLR BUCK PWM CM 36-SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 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) |
| LTC3716EG#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 36-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 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) |
| LTC3716EG#TR | 功能描述:IC REG CTRLR BUCK PWM CM 36-SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 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 |
| LTC3716EG#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 36-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 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) |
| LTC3717-1#PBF | 制造商:LINEAR 功能描述: 制造商:Linear Technology 功能描述: |
发布紧急采购，3分钟左右您将得到回复。