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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： | 5/28页 |
| 文件大小： | 290K |
| 代理商： | LT1576IS8#TR |
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13
LT1576/LT1576-5
APPLICATIONS INFORMATION
WU
U
V
I
ESR
ESL
dI
dt
RIPPLE =
()( )+()
P-P
Σ
Example: with VIN =10V, VOUT = 5V, L = 30H, ESR = 0.1,
ESL = 10nH:
IA
dI
dt
VA
mV
RIPPLE
P-P
=
()
()
()
=
==
=
()( )+
=+=
510 5
10 30 10
200 10
042
10
30 10
033 10
0 42
0 1
10 10
0 33 10
0 042 0 003
45
63
6
96
.
.
..
.
..
Σ
Output Capacitor Ripple Current (RMS):
I
VV
V
Lf V
RIPPLE RMS
OUT
IN
OUT
IN
( ) =
()
()
()( )( )
029
.
Ceramic Capacitors
Higher value, lower cost ceramic capacitors are now
becoming available in smaller case sizes. These are tempt-
ing for switching regulator use because of their very low
ESR. Unfortunately, the ESR is so low that it can cause
loop stability problems. Solid tantalum capacitor’s ESR
generates a loop “zero” at 5kHz to 50kHz that is instrumen-
tal in giving acceptable loop phase margin. Ceramic
capacitors remain capacitive to beyond 300kHz and usu-
ally resonate with their ESL before ESR becomes effective.
They are appropriate for input bypassing because of their
high ripple current ratings and tolerance of turn-on surges.
OUTPUT RIPPLE VOLTAGE
Figure 3 shows a typical output ripple voltage waveform
for the LT1576. Ripple voltage is determined by the high
frequency impedance of the output capacitor, and ripple
current through the inductor. Peak-to-peak ripple current
through the inductor into the output capacitor is:
I
VV
V
VL f
P
OUT
IN
OUT
IN
-P =
()
()
()( )( )
For high frequency switchers, the sum of ripple current
slew rates may also be relevant and can be calculated
from:
Σ
dI
dt
V
L
IN
=
Peak-to-peak output ripple voltage is the sum of a
triwave
created by peak-to-peak ripple current times ESR, and a
square wave created by parasitic inductance (ESL) and
ripple current slew rate. Capacitive reactance is assumed
to be small compared to ESR or ESL.
2
s/DIV
1576 F03
VOUT AT
IOUT = 1A
INDUCTOR
CURRENT
AT IOUT = 1A
VOUT AT
IOUT = 50mA
INDUCTOR
CURRENT
AT IOUT = 50mA
20mV/DIV
200mA/DIV
20mV/DIV
200mA/DIV
Figure 3. LT1576 Ripple Voltage Waveform
CATCH DIODE
The suggested catch diode (D1) is a 1N5818 Schottky, or
its Motorola equivalent, MBR130. It is rated at 1A average
forward current and 30V reverse voltage. Typical forward
voltage is 0.42V at 1A. The diode conducts current only
during switch off time. Peak reverse voltage is equal to
regulator input voltage. Average forward current in normal
operation can be calculated from:
I
IV
V
D AVG
OUT
IN
OUT
IN
( )=
()
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) |
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