參數(shù)資料
型號(hào): LTC1530IS8-3.3
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: Isolated Flyback Switching Regulator with 9V Output
中文描述: SWITCHING CONTROLLER, 350 kHz SWITCHING FREQ-MAX, PDSO8
封裝: 0.150 INCH, PLASTIC, SO-8
文件頁數(shù): 13/24頁
文件大小: 288K
代理商: LTC1530IS8-3.3
13
LTC1530
Inductor Selection
The inductor is often the largest component in an LTC1530
design and must be chosen carefully. Choose the inductor
value and type based on output slew rate requirements
and expected peak current. The required output slew rate
primarily controls the inductor value. The maximum rate
of rise of inductor current is set by the inductor’s value, the
input-to-output voltage differential and the LTC1530’s
maximum duty cycle. In a typical 5V input, 2.8V output
application, the maximum rise time will be:
DC
V
V
L
L
MAX
IN
OUT
=
1 85
A
s
μ
where L is the inductor value in
μ
H. With proper frequency
compensation, the combination of the inductor and output
capacitor values determine the transient recovery time. In
general, a smaller value inductor improves transient
response at the expense of ripple and inductor core
saturation rating. A 2
μ
H inductor has a 0.9A/
μ
s rise time
in this application, resulting in a 5.5
μ
s delay in responding
to a 5A load current step. During this 5.5
μ
s, the difference
between the inductor current and the output current is
made up by the output capacitor. This action causes a
temporary voltage droop at the output. To minimize this
effect, the inductor value should usually be in the 1
μ
H to
5
μ
H range for most 5V input LTC1530 circuits. Different
combinations of input and output voltages and expected
loads may require different values.
Once the required inductor value is selected, choose the
inductor core type based on peak current and efficiency
requirements. Peak current in the inductor is equal to the
maximum output load current plus half of the peak-to-
peak inductor ripple current. Inductor ripple current is set
by the inductor’s value, the input voltage, the output
voltage and the operating frequency. If the efficiency is
high, ripple current is approximately equal to:
(
(
where
f
OSC
= LTC1530 oscillator frequency
L
O
= Inductor value
I
V
V
V
f
L
V
RIPPLE
IN
OUT
)( )( )
OUT
OSC
O
IN
=
)(
)
Solving this equation for a typical 5V to 2.8V application
with a 2
μ
H inductor, ripple current is:
(
(
2 2
0 56
)(
)(
300
2
2
V
kHz
H
A
)
)
=
μ
P-P
Peak inductor current at 11.2A load:
11 2
2
2
12 2
A
A
A
+
=
The ripple current should generally fall between 10% and
40% of the output current. The inductor must be able to
withstand this peak current without saturating, and the
copper resistance in the winding should be kept as low as
possible to minimize resistive power loss. Note that in
circuits not employing the current limit function, the
current in the inductor may rise above this maximum
under short circuit or fault conditions; the inductor should
be sized accordingly to withstand this additional current.
Inductors with gradual saturation characteristics (example:
powdered iron) are often the best choice.
Input and Output Capacitors
A typical LTC1530 design places significant demands on
both the input and the output capacitors. During normal
steady load operation, a buck converter like the LTC1530
draws square waves of current from the input supply at the
switching frequency. The peak current value is equal to the
output load current plus 1/2 the peak-to-peak ripple cur-
rent. Most of this current is supplied by the input bypass
capacitor. The resulting RMS current flow in the input
capacitor heats it and causes premature capacitor failure
in extreme cases. Maximum RMS current occurs with
50% PWM duty cycle, giving an RMS current value equal
to I
OUT
/2. A low ESR input capacitor with an adequate
ripple current rating must be used to ensure reliable
operation. Note that capacitor manufacturers’ ripple cur-
rent ratings are often based on only 2000 hours (3 months)
lifetime at rated temperature. Further derating of the input
capacitor ripple current beyond the manufacturer’s speci-
fication is recommended to extend the useful life of the
circuit. Lower operating temperature has the largest effect
on capacitor longevity.
APPLICATIOU
W
U
U
相關(guān)PDF資料
PDF描述
LTC1530CS8-1.9 Isolated Flyback Switching Regulator with 9V Output
LTC1530CS8-2.5 Isolated Flyback Switching Regulator with 9V Output
LTC1536C Precision Triple Supply Monitor for PCI Applications
LTC1536 Advanced LinEPIC Self-Calibrating (Self-Cal) Precision Single Operational Amplifier 8-SOIC
LTC1536CMS8 Precision Triple Supply Monitor for PCI Applications
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC1530IS8PBF 制造商:Linear Technology 功能描述:DC-DC Controller Sync Buck 3.5-7V SOIC8
LTC1530IS8TR 制造商:Linear Technology 功能描述:
LTC1531CSW 功能描述:IC COMP ISOLATED SLF-PWRD 28SOIC RoHS:否 類別:集成電路 (IC) >> 線性 - 比較器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:通用 元件數(shù):1 輸出類型:CMOS,推挽式,滿擺幅,TTL 電壓 - 電源,單路/雙路(±):2.5 V ~ 5.5 V,±1.25 V ~ 2.75 V 電壓 - 輸入偏移(最小值):5mV @ 5.5V 電流 - 輸入偏壓(最小值):1pA @ 5.5V 電流 - 輸出(標(biāo)準(zhǔn)):- 電流 - 靜態(tài)(最大值):24µA CMRR, PSRR(標(biāo)準(zhǔn)):80dB CMRR,80dB PSRR 傳輸延遲(最大):450ns 磁滯:±3mV 工作溫度:-40°C ~ 85°C 封裝/外殼:6-WFBGA,CSPBGA 安裝類型:表面貼裝 包裝:管件 其它名稱:Q3554586
LTC1531CSW#PBF 功能描述:IC COMP ISOLATED SLF-PWRD 28SOIC RoHS:是 類別:集成電路 (IC) >> 線性 - 比較器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:通用 元件數(shù):1 輸出類型:CMOS,推挽式,滿擺幅,TTL 電壓 - 電源,單路/雙路(±):2.5 V ~ 5.5 V,±1.25 V ~ 2.75 V 電壓 - 輸入偏移(最小值):5mV @ 5.5V 電流 - 輸入偏壓(最小值):1pA @ 5.5V 電流 - 輸出(標(biāo)準(zhǔn)):- 電流 - 靜態(tài)(最大值):24µA CMRR, PSRR(標(biāo)準(zhǔn)):80dB CMRR,80dB PSRR 傳輸延遲(最大):450ns 磁滯:±3mV 工作溫度:-40°C ~ 85°C 封裝/外殼:6-WFBGA,CSPBGA 安裝類型:表面貼裝 包裝:管件 其它名稱:Q3554586
LTC1531CSW#TR 功能描述:IC COMP DIFF DUAL SELFPWR 28SOIC RoHS:否 類別:集成電路 (IC) >> 線性 - 比較器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:通用 元件數(shù):1 輸出類型:CMOS,推挽式,滿擺幅,TTL 電壓 - 電源,單路/雙路(±):2.5 V ~ 5.5 V,±1.25 V ~ 2.75 V 電壓 - 輸入偏移(最小值):5mV @ 5.5V 電流 - 輸入偏壓(最小值):1pA @ 5.5V 電流 - 輸出(標(biāo)準(zhǔn)):- 電流 - 靜態(tài)(最大值):24µA CMRR, PSRR(標(biāo)準(zhǔn)):80dB CMRR,80dB PSRR 傳輸延遲(最大):450ns 磁滯:±3mV 工作溫度:-40°C ~ 85°C 封裝/外殼:6-WFBGA,CSPBGA 安裝類型:表面貼裝 包裝:管件 其它名稱:Q3554586