- 您现在的位置：买卖IC网 > PDF目录44981 > LT1576IS8#TR (LINEAR TECHNOLOGY CORP) 3.5 A SWITCHING REGULATOR, 240 kHz SWITCHING FREQ-MAX, PDSO8 PDF资料下载
参数资料
| 型号： | LT1576IS8#TR |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 3.5 A SWITCHING REGULATOR, 240 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封装： | 0.150 INCH, PLASTIC, SOP-8 |
| 文件页数： | 11/28页 |
| 文件大小： | 290K |
| 代理商： | LT1576IS8#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页当前第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
19
LT1576/LT1576-5
APPLICATIONS INFORMATION
WU
U
At power-up, when VC is being clamped by the FB pin (see
Figure 2, Q2), the sync function is disabled. This allows the
frequency foldback to operate in the shorted output con-
dition. During normal operation, switching frequency is
controlled by the internal oscillator until the FB pin reaches
0.7V, after which the SYNC pin becomes operational. If no
synchronization is required, this pin should be connected
to ground.
THERMAL CALCULATIONS
Power dissipation in the LT1576 chip comes from four
sources: switch DC loss, switch AC loss, boost circuit
current, and input quiescent current. The following formu-
las show how to calculate each of these losses. These
formulas assume continuous mode operation, so they
should not be used for calculating efficiency at light load
currents.
Switch loss:
P
RI
V
ns I
V
f
SW
SW OUT
OUT
IN
OUT
IN
=
() ( )
+
()( )( )
2
60
Boost current loss:
P
VI
V
BOOST
OUT
IN
=
()
2
50
/
Quiescent current loss:
PV
V
Q
IN
OUT
IN
=
+
+
()
055 10
1 6 10
0 004
33
2
.
.
.
RSW = Switch resistance (≈ 0.2)
60ns = Equivalent switch current/voltage overlap time
f = Switch frequency
Example: with VIN = 10V, VOUT = 5V and IOUT = 1A:
P
W
PW
P
SW
BOOST
Q
= ()( ) ( ) +
()( )
=+
=
= () (
)
=
=
+
+
() ( )
=
02 1 5
10
60 10
1 10 2 00 10
01
012
0 22
51 50
10
005
10 0 55 10
5 1 6 10
5
0 004
10
0
2
93
2
33
2
.
..
.
/
.
.
.
..02W
Total power dissipation is 0.22 + 0.05 + 0.02 = 0.29W.
Thermal resistance for LT1576 package is influenced by
the presence of internal or backside planes. With a full
plane under the SO package, thermal resistance will be
about 80
°C/W. No plane will increase resistance to about
120
°C/W. To calculate die temperature, add in worst-case
ambient temperature:
TJ = TA + θJA (PTOT)
With the SO-8 package (
θJA = 80°C/W), at an ambient
temperature of 50
°C,
TJ = 50 + 80 (0.29) = 73.2°C
Die temperature is highest at low input voltage, so use
lowest continuous input operating voltage for thermal
calculations.
FREQUENCY COMPENSATION
Loop frequency compensation of switching regulators
can be a rather complicated problem because the reactive
components used to achieve high efficiency also intro-
duce multiple poles into the feedback loop. The inductor
and output capacitor on a conventional step-down con-
verter actually form a resonant tank circuit that can exhibit
peaking and a rapid 180
° phase shift at the resonant
frequency. By contrast, the LT1576 uses a “current mode”
architecture to help alleviate phase shift created by the
inductor. The basic connections are shown in Figure 9.
Figure 10 shows a Bode plot of the phase and gain of the
power section of the LT1576, measured from the VC pin to
相关PDF资料 |
PDF描述 |
|---|---|
| LT1634CMS8-2.5#PBF | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 2.5 V, PDSO8 |
| LT1634CMS8-1.25#PBF | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 1.25 V, PDSO8 |
| LT1634CMS8-1.25#TRPBF | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 1.25 V, PDSO8 |
| LT1680ISW#TRPBF | SWITCHING CONTROLLER, 200 kHz SWITCHING FREQ-MAX, PDSO16 |
| LT1702-7FB1 | 1-OUTPUT 500 W AC-DC REG PWR SUPPLY MODULE |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1577 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Ultrafast Transient Response, Low Dropout Regulators Adjustable and Fixed |
| LT1577CS-3.3/2.8 | 功能描述:IC REG CTRLR DUAL OUT 16SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性晶体管驱动器 系列:- 产品培训模块:More Information on LDOs 标准包装:2,500 系列:- 类型:正，固定式 输出数:2 输出电压:2.8V，3.3V 电流 - 电源:12mA 输入电压:5 V ~ 22 V 工作温度:0°C ~ 70°C 封装/外壳:16-SOIC（0.154"，3.90mm 宽） 供应商设备封装:16-SOIC 包装:带卷 (TR) |
| LT1577CS-3.3/2.8#PBF | 功能描述:IC REG CTRLR DUAL OUT 16SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性晶体管驱动器 系列:- 产品培训模块:More Information on LDOs 标准包装:2,500 系列:- 类型:正，固定式 输出数:2 输出电压:2.8V，3.3V 电流 - 电源:12mA 输入电压:5 V ~ 22 V 工作温度:0°C ~ 70°C 封装/外壳:16-SOIC（0.154"，3.90mm 宽） 供应商设备封装:16-SOIC 包装:带卷 (TR) |
| LT1577CS-3.3/2.8#TR | 功能描述:IC REG CTRLR DUAL OUT 16SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性晶体管驱动器 系列:- 产品培训模块:More Information on LDOs 标准包装:2,500 系列:- 类型:正，固定式 输出数:2 输出电压:2.8V，3.3V 电流 - 电源:12mA 输入电压:5 V ~ 22 V 工作温度:0°C ~ 70°C 封装/外壳:16-SOIC（0.154"，3.90mm 宽） 供应商设备封装:16-SOIC 包装:带卷 (TR) |
| LT1577CS-3.3/2.8#TRPBF | 功能描述:IC REG CTRLR DUAL OUT 16SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性晶体管驱动器 系列:- 产品培训模块:More Information on LDOs 标准包装:2,500 系列:- 类型:正，固定式 输出数:2 输出电压:2.8V，3.3V 电流 - 电源:12mA 输入电压:5 V ~ 22 V 工作温度:0°C ~ 70°C 封装/外壳:16-SOIC（0.154"，3.90mm 宽） 供应商设备封装:16-SOIC 包装:带卷 (TR) |
发布紧急采购，3分钟左右您将得到回复。