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参数资料
| 型号： | LT1575CS8#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 10/20页 |
| 文件大小： | 312K |
| 描述： | IC REG CTRLR SGL POS ADJ 8-SOIC |
| 产品培训模块： | More Information on LDOs |
| 标准包装： | 100 |
| 类型： | 正，可调式 |
| 输出数： | 1 |
| 输出电压： | 可调 |
| 电流 - 电源： | 12mA |
| 输入电压： | 10 V ~ 20 V |
| 工作温度： | 0°C ~ 70°C |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 8-SOIC |
| 包装： | 管件 |
| 产品目录页面： | 1328 (CN2011-ZH PDF) |
10
LT1575/LT1577
APPLICATIONS INFORMATION
U
U
Introduction
The current generation of microprocessors place strin-
gent demands on the power supply that powers the
processor core. These microprocessors cycle load cur-
rent from near zero to amps in tens of nanoseconds.
Output voltage tolerances as low as ?00mV include
transient response as part of the specification. Some
microprocessors require only a single output voltage from
which the core and I/O circuitry operate. Other higher
performance processors require a separate power supply
voltage for the processor core and the I/O circuitry. These
requirements mandate the need for very accurate, very
high speed regulator circuits.
Previously employed solutions included monolithic
3-terminal linear regulators, PNP transistors driven by low
cost control circuits and simple buck converter switching
regulators. The 3-terminal regulator achieves a high level
of integration, the PNP driven regulator achieves very low
dropout performance and the switching regulator achieves
high electrical efficiency.
However, the common trait manifested by these solutions
is that transient response is measured in many microsec-
onds. This fact translates to a regulator output decoupling
capacitor scheme that requires several hundred microfar-
ads of very low ESR bulk capacitance using multiple
capacitors surrounding the CPU. This required bulk ca-
pacitance is in addition to the ceramic decoupling capaci-
tor network that handles the transient load response
during the first few hundred nanoseconds as well as
providing microprocessor clock frequency noise immu-
nity. The combined cost of all capacitors is a significant
percentage of the total power supply cost.
The LT1575/LT1577 family of single/dual controller ICs
are unique, easy to use devices that drive external
N-channel MOSFETs as source followers and permit a user
to realize an extremely low dropout, ultrafast transient
response regulator. These circuits achieve superior regu-
lator bandwidth and transient load performance by com-
pletely eliminating expensive tantalum or bulk electrolytic
capacitors in the most modern and demanding micropro-
cessor applications. For example, a 200MHz Pentium
processor can operate with only the recommended 24 1礔
ceramic capacitors. Users benefit directly by saving sig-
nificant cost as all additional bulk capacitance is removed.
The additional savings of insertion cost, purchasing/in-
ventory cost and board space are readily apparent.
Precision-trimmed adjustable and fixed output voltage
versions accommodate any required microprocessor
power supply voltage. Proper selection of the N-channel
MOSFET R
DS(ON)
allows user-settable dropout voltage
performance. The only output capacitors required are the
high frequency ceramic decoupling capacitors. This regu-
lator design provides ample bandwidth and responds to
transient load changes in a few hundred nanoseconds
versus regulators that respond in many microseconds.
The ceramic capacitor network generally consists of 10 to
24 1uF capacitors for individual microprocessor require-
ments. The LT1575/LT1577 family also incorporates cur-
rent limiting for no additional system cost, provides on/off
control and overvoltage protection or thermal shutdown
with simple external components.
Therefore, the unique design of these new ICs combines
the benefits of low dropout voltage, high functional inte-
gration, precision performance and ultrafast transient
response, as well as providing significant cost savings on
the output capacitance needed in fast load transient appli-
cations. As lower input/output differential voltage applica-
tions become increasingly prevalent, an LT1575-based
solution achieves comparable efficiency performance with
a switching regulator at an appreciable cost savings.
The new LT1575/LT1577 family of low dropout regulator
controller ICs step to the next level of performance re-
quired by system designers for the latest generation
motherboards and microprocessors. The simple versatil-
ity and benefits derived from these circuits allow the
power supply needs of todays high performance micro-
processors to be met with ease.
Block Diagram Operation
The primary block diagram elements consist of a simple
feedback control loop and the secondary block diagram
elements consist of multiple protection functions. Exam-
ining the block diagram for the LT1575, a start-up circuit
provides controlled start-up for the IC, including the
precision-trimmed bandgap reference, and establishes all
internal current and voltage biasing.
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相关代理商/技术参数 |
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|---|---|
| LT1576 | 制造商:LINER 制造商全称:Linear Technology 功能描述:1.5A, 200kHz Step-Down Switching Regulator |
| LT-1576-111-012 | 制造商:Carling Technologies 功能描述:LT-SERIES TOGGLE SWITCH - Bulk |
| LT1576-5 | 制造商:LINER 制造商全称:Linear Technology 功能描述:1.5A, 200kHz Step-Down Switching Regulator |
| LT1576C | 制造商:LINER 制造商全称:Linear Technology 功能描述:1.5A, 200kHz Step-Down Switching Regulator |
| LT1576CS8 | 功能描述:IC REG BUCK ADJ 1.5A 8SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
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