- 您现在的位置：买卖IC网 > PDF目录44991 > LTC3568EDD#TR (LINEAR TECHNOLOGY CORP) 4 A SWITCHING REGULATOR, 4000 kHz SWITCHING FREQ-MAX, PDSO10 PDF资料下载
参数资料
| 型号： | LTC3568EDD#TR |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 4 A SWITCHING REGULATOR, 4000 kHz SWITCHING FREQ-MAX, PDSO10 |
| 封装： | 3 X 3 MM, PLASTIC, MO-229WEED-2, DFN-10 |
| 文件页数： | 4/18页 |
| 文件大小： | 300K |
| 代理商： | LTC3568EDD#TR |
LTC3568
3568fa
applicaTions inForMaTion
that will give a sense of the overall loop stability without
breaking the feedback loop.
Switching regulators take several cycles to respond to a
step in load current. When a load step occurs, VOUT im-
mediatelyshiftsbyanamountequalto
ΔILOADESR,where
ESR is the effective series resistance of COUT. ΔILOAD also
begins to charge or discharge COUT generating a feedback
error signal used by the regulator to return VOUT to its
steady-state value. During this recovery time, VOUT can
be monitored for overshoot or ringing that would indicate
a stability problem.
The initial output voltage step may not be within the
bandwidth of the feedback loop, so the standard second
order overshoot/DC ratio cannot be used to determine
phase margin. The gain of the loop increases with R and
the bandwidth of the loop increases with decreasing C.
If R is increased by the same factor that C is decreased,
the zero frequency will be kept the same, thereby keeping
the phase the same in the most critical frequency range
of the feedback loop. In addition, a feedforward capacitor
CF can be added to improve the high frequency response,
as shown in Figure 5. Capacitor CF provides phase lead by
creating a high frequency zero with R2 which improves
the phase margin.
Theoutputvoltagesettlingbehaviorisrelatedtothestability
of the closed-loop system and will demonstrate the actual
overall supply performance. For a detailed explanation of
optimizing the compensation components, including a
review of control loop theory, refer to Linear Technology
Application Note 76.
Although a buck regulator is capable of providing the full
output current in dropout, it should be noted that as the
inputvoltageVINdropstowardVOUT,theloadstepcapability
does decrease due to the decreasing voltage across the
inductor. Applications that require large load step capabil-
ity near dropout should use a different topology such as
SEPIC, Zeta or single inductor, positive buck/boost.
Insomeapplications,amoreseveretransientcanbecaused
by switching in loads with large (>1uF) input capacitors.
Thedischargedinputcapacitorsareeffectivelyputinparal-
lel with COUT, causing a rapid drop in VOUT. No regulator
can deliver enough current to prevent this problem, if the
switchconnectingtheloadhaslowresistanceandisdriven
quickly.Thesolutionistolimittheturn-onspeedoftheload
switchdriver.Ahotswapcontrollerisdesignedspecifically
for this purpose and usually incorporates current limiting,
short-circuit protection, and soft-starting.
EfficiencyConsiderations
The percent efficiency of a switching regulator is equal to
the output power divided by the input power times 100%.
It is often useful to analyze individual losses to determine
what is limiting the efficiency and which change would
produce the most improvement. Percent efficiency can
be expressed as:
%Efficiency = 100% – (L1 + L2 + L3 + ...)
where L1, L2, etc. are the individual losses as a percent-
age of input power.
Although all dissipative elements in the circuit produce
losses, four main sources usually account for most of
PVIN
LTC3568
PGOOD
SW
SVIN
SYNC/MODE
VFB
ITH
SHDN/RT
L1
VIN
2.5V
TO 5.5V
SGND PGND
R5
CF
RT
RC
R1
R2
3568 F05
CC
CITH
C5
VOUT
CIN
+
C6
PGND
SGND
PGND
SGND
SGND SGND
GND
PGND
COUT
R6
C8
SGND
Figure5.LTC3568GeneralSchematic
相关PDF资料 |
PDF描述 |
|---|---|
| LTC3568IDD | 4 A SWITCHING REGULATOR, 4000 kHz SWITCHING FREQ-MAX, PDSO10 |
| LTC3568IDD#TR | 4 A SWITCHING REGULATOR, 4000 kHz SWITCHING FREQ-MAX, PDSO10 |
| LTC3569IFE#PBF | 2.5 A SWITCHING REGULATOR, 3000 kHz SWITCHING FREQ-MAX, PDSO16 |
| LTC3569IUD#PBF | 2.5 A SWITCHING REGULATOR, 3000 kHz SWITCHING FREQ-MAX, PQCC20 |
| LTC3569IUDC#PBF | 2.5 A SWITCHING REGULATOR, 3000 kHz SWITCHING FREQ-MAX, PQCC20 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3568IDD#PBF | 功能描述:IC REG BUCK SYNC ADJ 1.8A 10DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
| LTC3568IDD#PBF | 制造商:Linear Technology 功能描述:DP-SWREG/Monolithic 4MHz 1.8A Synch St 制造商:Linear Technology 功能描述:DP-SWREG/Monolithic, 4MHz, 1.8A Synch St |
| LTC3568IDD#TRPBF | 功能描述:IC REG BUCK SYNC ADJ 1.8A 10DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
| LTC3569 | 制造商:LINER 制造商全称:Linear Technology 功能描述:7-Channel Confi gurable High Power PMIC |
| LTC3569EFE | 制造商:Linear Technology 功能描述:DC/DC Converter Chip |
发布紧急采购，3分钟左右您将得到回复。