參數(shù)資料
型號: LT1175
廠商: Linear Technology Corporation
英文描述: 500mA Negative Low Dropout Micropower Regulator(500mA,F負(fù)輸出,低壓差,微功耗穩(wěn)壓器)
中文描述: 500mA的低壓差微負(fù)穩(wěn)壓器(500mA的,女負(fù)輸出,低壓差,微功耗穩(wěn)壓器)
文件頁數(shù): 10/12頁
文件大?。?/td> 124K
代理商: LT1175
10
LT1175
APPLICATIO
S I
FOR
ATIO
U
W
U
U
T
A
T
MAX
= Maximum LT1175 die temperature (125
°
C for
commercial and industrial grades)
θ
JA
= LT1175 thermal resistance, junction to ambient
V
IN
= Maximum continuous input voltage at maximum
load current
= Maximum ambient temperature
I
LOAD
= Maximum load current
Example: LT1175S8 with I
LOAD
= 200mA, V
OUT
= 5V,
V
IN
= 7V, T
A
= 60
°
C. Maximum die temperature for the
LT1175S8 is 125
°
C. Thermal resistance from Table 2 is
found to be 80
°
C/W.
Die Temperature = 60 + 80 (0.2A)(8 – 5) = 108
°
C
Maximum
Maximum Continuous
Input Voltage
(for Thermal Considerations)
W
V
Power Dissipation =125±60
80
125±60
( )
=
=
+ =
5
081
80 02
9
.
Output Voltage Reversal
The LT1175 is designed to tolerate an output voltage
reversal of up to 2V. Reversal might occur, for instance, if
the output was shorted to a positive 5V supply. This would
almost surely destroy IC devices connected to the negative
output. Reversal could also occur during start-up if the
positive supply came up first and loads were connected
between the positive and negative supplies. For these
reasons, it is always good design practice to add a reverse
biased diode fromeach regulator output to ground to limt
output voltage reversal The diode should be rated to
handle full negative load current for start-up situations, or
the short-circuit current of the positive supply if supply-to-
supply shorts must be tolerated.
Input Voltage Lower Than Output
Linear Technology’s positive low dropout regulators
LT1121 and LT1129, will not draw large currents if the
input voltage is less than the output. These devices use a
lateral PNP power transistor structure that has 40V emitter
base breakdown voltage. The LT1175, however, uses an
NPNpower transistor structure that has a parasitic diode
between the input and output of the regulator Reverse
voltages between input and output above 1V will damage
the regulator if large currents are allowed to flow. Simply
disconnecting the input source with the output held up will
not cause damage even though the input-to-output volt-
age will become slightly reversed.
High Frequency Ripple Rejection
The LT1175 will sometimes be powered from switching
regulators that generate the unregulated or quasi-regu-
lated input voltage. This voltage will contain high fre-
quency ripple that must be rejected by the linear regulator.
Special care was taken with the LT1175 to maximize high
frequency ripple rejection, but as with any micropower
design, rejection is strongly affected by ripple frequency.
The graph in the Typical Performance Characteristics
section shows 60dB rejection at 1kHz, but only 15dB
rejection at 100kHz for the 5V part. Photographs in Figures
4a and 4b show actual output ripple waveforms with
square wave and triwave input ripple.
C
OUT
= 4.7
μ
F TANT
C
OUT
= 1
μ
F TANT
5
μ
s/DIV
1175 F04
Figure 4a.
C
OUT
= 4.7
μ
F TANT
C
OUT
= 1
μ
F TANT
2
μ
s/DIV
Figure 4b.
1175 F04
INPUT
RIPPLE
100mV/DIV
OUTPUT
100mV/DIV
f = 100kHz
f = 50kHz
OUTPUT
20mV/DIV
INPUT
RIPPLE
100mV/DIV
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LT1175CN8 功能描述:IC REG LDO NEG ADJ .5A 8-DIP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 系列:- 標(biāo)準(zhǔn)包裝:800 系列:- 穩(wěn)壓器拓?fù)浣Y(jié)構(gòu):正,固定式 輸出電壓:2.5V 輸入電壓:最高 16V 電壓 - 壓降(標(biāo)準(zhǔn)):0.7V @ 4A 穩(wěn)壓器數(shù)量:1 電流 - 輸出:4A 電流 - 限制(最小):4.2A 工作溫度:0°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:TO-263-6,D²Pak(5 引線+接片),TO-263BA 供應(yīng)商設(shè)備封裝:TO-263-5 包裝:帶卷 (TR) 其它名稱:AP1184K525L-13AP1184K525LDITR