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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： | 17/28页 |
| 文件大小： | 290K |
| 代理商： | LT1576IS8#TR |
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24
LT1576/LT1576-5
APPLICATIONS INFORMATION
WU
U
with large inductors. Output ripple voltage for the positive-
to-negative converter will be much higher than a buck
converter. Ripple current in the output capacitor will also
be much higher. The following equations can be used to
calculate operating conditions for the positive-to-negative
converter.
Maximum load current:
I
VV
f L
VV
V
MAX
P
IN
OUT
IN
OUT
IN
OUT
IN
OUT
F
=
()( )
+
()( )( )
()
()
+
()
+
()
2
035
.
IP = Maximum rated switch current
VIN = Minimum input voltage
VOUT = Output voltage
VF = Catch diode forward voltage
0.35 = Switch voltage drop at 1.5A
Example: with VIN(MIN) = 5.5V, VOUT = 5V, L = 30H,
VF = 0.5V, IP = 1.5A: IMAX = 0.6A. Note that this equation
does not take into account that maximum rated switch
current (IP) on the LT1576 is reduced slightly for duty
cycles above 50%. If duty cycle is expected to exceed 50%
(input voltage less than output voltage), use the actual IP
value from the Electrical Characteristics table.
Operating duty cycle:
DC
VV
V
OUT
F
IN
OUT
F
=
+
03
.
(This formula uses an average value for switch loss, so it
may be several percent in error.)
With the conditions above:
DC
=
+
+ +
=
50 5
55
03
5
0 5
51
.
..
.
%
This duty cycle is close enough to 50% that IP can be
assumed to be 1.5A.
OUTPUT DIVIDER
If the adjustable part is used, the resistor connected to
VOUT (R2) should be set to approximately 5k. R1 is
calculated from:
R
RVOUT
1
21 21
121
=
()
.
INDUCTOR VALUE
Unlike buck converters, positive-to-negative converters
cannot use large inductor values to reduce output ripple
voltage. At 200kHz, values larger than 75
H make almost
no change in output ripple. The graph in Figure 16 shows
peak-to-peak output ripple voltage for a 5V to – 5V con-
verter versus inductor value. The criteria for choosing the
INDUCTOR SIZE (
H)
0
OUTPUT
RIPPLE
VOLTAGE
(mV
P-P
)
150
120
90
60
30
0
60
1576 F16
15
30
45
75
DISCONTINUOUS
ILOAD = 0.25A
DISCONTINUOUS
ILOAD = 0.1A
5V TO –5V CONVERTER
OUTPUT CAPACITOR’S
ESR = 0.1
CONTINUOUS
ILOAD > 0.38A
Figure 16. Ripple Voltage on Positive-to-Negative Converter
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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