- 您現(xiàn)在的位置：買(mǎi)賣(mài)IC網(wǎng) > PDF目錄374727 > SC4205 (Semtech Corporation) Very Low Dropout 1 Amp Regulator With Enable PDF資料下載
參數(shù)資料
| 型號(hào)： | SC4205 |
| 廠(chǎng)商： | Semtech Corporation |
| 英文描述： | Very Low Dropout 1 Amp Regulator With Enable |
| 中文描述： | 非常低壓差穩(wěn)壓1安培啟用 |
| 文件頁(yè)數(shù)： | 6/8頁(yè) |
| 文件大?。?/td> | 227K |
| 代理商： | SC4205 |
6
2004 Semtech Corp.
www.semtech.com
SC4205
POWER MANAGEMENT
Applications Information
Introduction
The SC4205 is intended for applications such as
graphics cards where high current capability and very low
dropout voltage are required. It provides a very simple,
low cost solution that uses very little pcb real estate.
Additional features include an enable pin to allow for a
very low power consumption standby mode, and a fully
adjustable output.
Component Selection
Input capacitor:
a 4.7μF ceramic capacitor is
recommended. 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. Additional capacitance
may be added if required by the application.
Output capacitor:
a minimum bulk capacitance of 2.2μF,
along with a 0.1μF ceramic decoupling capacitor is
recommended. Increasing the bulk capacitance will
improve the overall transient response. The use of
multiple lower value ceramic capacitors in parallel to
achieve the desired bulk capacitance will not cause
stability issues. Although designed for use with ceramic
output capacitors, the SC4205 is extremely tolerant of
output capacitor ESR values and thus will also work
comfortably with tantalum output capacitors. For refer-
ence, the phase-margin contour of Figure 1 can be used
to choose an appropriate output capacitor for a given
stability requirement.
Noise immunity:
in very electrically noisy environments,
it is recommended that 0.1μF ceramic capacitors be
placed from IN to GND and OUT to GND as close to the
device pins as possible.
External voltage selection resistors:
the use of 1%
resistors, and designing for a current flow
≥
10μA is
recommended to ensure a well regulated output (thus
R2
≤
120k
).
Thermal Considerations
The power dissipation in the SC4205 is approximately
equal to the product of the output current and the input
to output voltage differential:
(
)
O
D
I
VOUT
VIN
P
≈
The absolute worst-case dissipation is given by:
(
VIN
)
)
(
)
(
)
(
)
(
)
(
)
(
MAX
Q
MAX
MAX
O
MIN
MAX
MAX
D
I
VIN
I
VOUT
P
+
=
For a typical scenario, V
IN
= 3.3V ± 5%, V
OUT
= 2.8V and
I
O
= 1A, therefore:
V
IN(MAX)
= 3.465V, V
OUT(MIN)
= 2.744V and I
Q(MAX)
= 1.75mA,
Thus P
D(MAX)
= 727mW.
Using this figure, and assuming T
= 70°C, we can
calculate the maximum thermal impedance allowable to
maintain T
J
≤
150°C:
(
)
(
=
)
W
C
P
T
T
R
MAX
D
MAX
A
MAX
J
MAX
A
J
TH
/
110
727
.
70
150
)
(
)
(
)
(
)
)(
(
°
=
=
This should be achievable for the SOIC-8EDP package
using pcb copper area to aid in conducting the heat away,
such as one square inch of copper connected to the pins
of the device. Internal ground/power planes and air flow
will also assist in removing heat. For higher ambient tem-
peratures it may be necessary to use additional copper
area.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SC4205EVB | Very Low Dropout 1 Amp Regulator With Enable |
| SC4205IS-2.5TR | Very Low Dropout 1 Amp Regulator With Enable |
| SC4205IS-X.XTR | Very Low Dropout 1 Amp Regulator With Enable |
| SC4205IS-X.XTRT | Very Low Dropout 1 Amp Regulator With Enable |
| SC420A | High Speed, Combi-SenseTM, Synchronous Power MOSFET Driver for Mobile Applications |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SC4205EVB | 制造商:SEMTECH 制造商全稱(chēng):Semtech Corporation 功能描述:Very Low Dropout 1 Amp Regulator With Enable |
| SC4205IS-1.8TRT | 制造商:Semtech Corporation 功能描述:LDO Regulator Pos 1.8V 1A 8-Pin SOIC T/R 制造商:SEMTECH 功能描述:0 |
| SC4205IS-2.5.TRT | 制造商:SEMTECH 功能描述:I.C. |
| SC4205IS-2.5TR | 制造商:SEMTECH 制造商全稱(chēng):Semtech Corporation 功能描述:Very Low Dropout 1 Amp Regulator With Enable |
| SC4205IS-2.5TRT | 制造商:Semtech Corporation 功能描述:Linear Voltage Regulator IC 制造商:Semtech Corporation 功能描述:SC Series 5.5 V 1 A Surface Mount Very Low Dropout Voltage Regulator - SOIC-8EDP 制造商:Semtech Corporation 功能描述:IC, LDO VOLT REG, 2.5V, 1A, SOIC-8; Primary Input Voltage:5.5V; Output Voltage Fixed:2.5V; Dropout Voltage Vdo:180mV; No. of Pins:8; Output Current:1A; Operating Temperature Min:-40C; Operating Temperature Max:85C; No. of Outputs:1;RoHS Compliant: Yes 制造商:SEMTECH 功能描述:TVS diode array |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。