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参数资料
| 型号： | SC1531ACSTR |
| 厂商： | Semtech Corporation |
| 英文描述： | 200mA & 250mA SmartLDOs |
| 中文描述： | 200毫安 |
| 文件页数： | 10/11页 |
| 文件大小： | 264K |
| 代理商： | SC1531ACSTR |
8
2000 Semtech Corp.
www.semtech.com
SC1531(A)
POWER MANAGEMENT
Introduction
The SC1531(A) is intended for applications such as power
managed PCI and network interface cards (NICs), where
operation from a 3.3V VAUX supply may be required when
the 5V supply has been shut down. It provides a very
simple, low cost solution that uses very little pcb real
estate. During regular operation, 3.3V power for the PCI
card is provided by the SC1531(A)s on-board low
dropout regulator, generated from the 5V supply. When
the 5V supply is removed and 3.3V VAUX is available, the
SC1531(A) connects this supply directly to its output
using a tiny SOT-23 external p-channel FET. Connection
of pin 3 (VAUX) to the 3.3V supply is optional, and adds
active pull-down to the Drive pin.
Component Selection
Output capacitors - Semtech recommends a minimum
bulk capacitance of 4.7F at the output, along with a
0.1F ceramic decoupling capacitor. Increasing the bulk
capacitance will improve the overall transient response.
The device is very tolerant of capacitor value and ESR
variations, in fact, any combination of capacitors with
C 4.7F and ESR < 1W is sufficient for stability. This
target is easily met using surface mount ceramic or
tantalum capacitors.
Input capacitors (5V) - Semtech recommends the use of
a 4.7F ceramic or tantalum capacitor plus a 0.1F
ceramic capacitor at the input. This allows for the device
being some distance from any bulk capacitance on the
rail. Additionally, input droop due to load transients is
reduced, improving load transient response.
Input capacitors (3.3V) - Semtech recommends
decoupling this pin (if used) with a 0.1F ceramic
capacitor.
P-channel bypass FET - selection of the external FET is
determined by two main requirements:
1) the FET has to have a very low gate threshold
(typically ~1V) in order to be sufficiently turned on with
V
GS 3.3V.
2) the FET R
DS(ON) must be low enough such that:
(
)
MIN
(
)
ON
(
DS
)
MAX
(
O
VO
R
I
VAUX
≥
Typical Characteristics (Cont.)(1)
Load Transient Response
Trace 1: VO
Trace 2: I
O stepping from 0mA to 200mA
Load Transient Response
Trace 1: VO
Trace 2: I
O stepping from 200mA to 0mA
Applications Information
Notes:
(1) In Application Circuit on page 1.
(2) I
O = 200mA.
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相关代理商/技术参数 |
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|---|---|
| SC1531CSTR | 制造商:Semtech Corporation 功能描述:IC REG LDO LIN POS 0.2A 8SOIC T/R |
| SC1532 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:400mA SmartLDOTM with Internal Pass MOSFET |
| SC1532CS | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:400mA SmartLDOTM with Internal Pass MOSFET |
| SC1532CS.TR | 制造商:Semtech Corporation 功能描述:3.3 V FIXED POSITIVE LDO REGULATOR, 8 Pin Plastic SOP |
| SC1534 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:400mA SmartLDOTM |
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