- 您现在的位置：买卖IC网 > PDF目录4953 > LTC3880EUJ#PBF (Linear Technology)IC REG CTRLR BUCK PWM CM 40-QFN PDF资料下载
参数资料
| 型号： | LTC3880EUJ#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 37/112页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 40-QFN |
| 软件下载： | LTpowerPlay™ |
| 标准包装： | 61 |
| 系列： | PolyPhase® |
| PWM 型： | 电流模式 |
| 输出数： | 2 |
| 频率 - 最大： | 1MHz |
| 电源电压： | 4.5 V ~ 24 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 ~ 105°C |
| 封装/外壳： | 40-WFQFN 裸露焊盘 |
| 包装： | 管件 |
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页当前第37页第38页第39页第40页第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页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页第69页第70页第71页第72页第73页第74页第75页第76页第77页第78页第79页第80页第81页第82页第83页第84页第85页第86页第87页第88页第89页第90页第91页第92页第93页第94页第95页第96页第97页第98页第99页第100页第101页第102页第103页第104页第105页第106页第107页第108页第109页第110页第111页第112页
LTC3880/LTC3880-1
APPLICATIONS INFORMATION
The Typical Application on the back page is a basic LTC3880
application circuit. The LTC3880 can be configured to use
either DCR (inductor resistance) sensing or low value
resistor sensing. The choice between the two current
sensing schemes is largely a design trade-off between
cost, power consumption and accuracy. DCR sensing
is becoming popular because it saves expensive current
sensing resistors and is more power efficient, especially
in high current applications. The LTC3880 can nominally
account for the temperature dependency of the DCR sens-
ing element. The accuracy of the current reading and cur-
rent limit are typically limited by the accuracy of the DCR
resistor (accounted for in the IOUT_CAL_GAIN parameter
of the LTC3880). Thus current sensing resistors provide
the most accurate current sense and limiting for the ap-
plication. Other external component selection is driven
by the load requirement, and begins with the selection of
R SENSE (if R SENSE is used) and inductor value. Next, the
power MOSFETs are selected. Then the input and output
capacitors are selected. Finally the current limit is selected.
All of these components and ranges are required to be
determined prior to calculating the external compensation
components. The current limit range is required because
the two ranges (25mV to 50mV vs 37.5mV to 70mV) have
different EA gains set with bit 7 of the MFR_PWM_MODE_
LTC3880 command. The voltage RANGE bit also modifies
the loop gain and impacts the compensation network set
with bits 5, 6 of MFR_PWM_CONFIG_LTC3880. All other
programmable parameters do not affect the loop gain,
allowing parameters to be modified without impact to the
transient response to load.
CURRENT LIMIT PROGRAMMING
The LTC3880 has two ranges of current limit programming
and a total of eight levels within each range. Refer to the
IOUT_OC_FAULT_LIMIT section of the PMBus commands.
Within each range the error amp gain is fixed, resulting in
constant loop gain. The LTC3880 will account for the DCR
of the inductor and automatically update the current limit as
the inductor temperature changes. The temperature coef-
ficient of the DCR is stored in the MFR_IOUT_TC register.
For the best current limit accuracy, use the 75mV setting.
The 25mV setting will allow for the use of very low DCR
inductors or sense resistors, but at the expense of cur-
rent limit accuracy. Keep in mind this operation is on a
cycle-by-cycle basis and is only a function of the peak in-
ductor current. The average inductor current is monitored
by the ADC converter and can provide a warning if too
much average output current is detected. The overcurrent
fault is detected when the ITH voltage hits the maximum
value. The digital processor within the LTC3880 provides
the ability to either ignore the fault, shut down and latch off
or shut down and retry indefinitely (hiccup). Refer to the
overcurrent portion of the Operation section for more detail.
I SENSE+ AND I SENSE– PINS
The I SENSE+ and I SENSE– pins are the inputs to the current
comparators and the A/D. The common mode input voltage
range of the current comparators is 0V to 5.5V. Both the
SENSE pins are high impedance inputs with small base
currents typically less than 1μA. When the I SENSE pins
ramp up from 0V to 1.4V, the small base currents flow
out of the SENSE pins. When the I SENSE pins are greater
than 1.4V, the base currents flow into the I SENSE pins. The
high impedance inputs to the current comparators allow
accurate DCR sensing. Do not to float these pins during
normal operation.
Filter components mutual to the I SENSE lines should be
placed close to the IC. The positive and negative traces
should be routed differentially and Kelvin connected to
the current sense element, see Figure 17. A non-Kelvin
connection elsewhere can add parasitic inductance and
capacitance to the current sense element, degrading
the information at the sense terminals and making the
programmed current limit unpredictable. In a PolyPhase
system, poor placement of the sensing element will result in
sub-optimal current sharing between power stages. If DCR
sensing is used (Figure 18a), sense resistor R1 should be
placed close to the switching node to prevent noise from
TO SENSE FILTER,
NEXT TO THE CONTROLLER
C OUT
INDUCTOR OR R SENSE 3880 F17
Figure 17. Optimal Sense Line Placement
3880fb
For more information www.linear.com/LTC3880
37
相关PDF资料 |
PDF描述 |
|---|---|
| UCD0J152MNL1GS | CAP ALUM 1500UF 6.3V 20% SMD |
| RMC28DRTI-S93 | CONN EDGECARD 56POS DIP .100 SLD |
| MCP1703-2502E/DB | IC REG LDO 2.5V .25A SOT-223-3 |
| RCE20DHFD | CONN EDGECARD 40POS 1MM SMD |
| RBE20DHFD | CONN EDGECARD 40POS 1MM SMD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3880IUJ#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 40-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: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 |
| LTC3880IUJ#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 40-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: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 |
| LTC3880IUJ-1#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 40-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: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 |
| LTC3880IUJ-1#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 40-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: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 |
| LTC3883EUH#PBF | 制造商:Linear Technology 功能描述:IC REG CTRLR BUCK PWM VM 32-QFN 制造商:Linear Technology 功能描述:BUCK CNTRL 24V 1MHZ 0.5/5.5V 32QFN 制造商:Linear Technology 功能描述:BUCK, CNTRL, 24V, 1MHZ, 0.5/5.5V, 32QFN 制造商:Linear Technology 功能描述:PWM CONTROLLER, BUCK, 1MHZ, 24V, QFN-32, Input Voltage:24V, Output Voltage:5.5V, Output Current:30A, Supply Voltage Min:4.5V, Supply Voltage Max:24V, Digital IC Case Style:QFN, No. of Pins:32, Frequency:1MHz, MSL:MSL 1 - Unlimited , RoHS Compliant: Yes 制造商:Linear Technology 功能描述:DP-SWREG/Controller, Digitally Programmable, Multiphase Step-Down DC/DC Controll |
发布紧急采购，3分钟左右您将得到回复。