參數(shù)資料
型號(hào)： S817
廠商： Seiko Instruments Inc.
英文描述： SUPER-SMALL PACKAGE CMOS VOLTAGE REGULATOR
中文描述： 超小型封裝CMOS電壓穩(wěn)壓器
文件頁(yè)數(shù)： 15/50頁(yè)
文件大小： 830K
代理商： S817
Rev.3.0
_00
SUPER-SMALL PACKAGE CMOS VOLTAGE REGULATOR
S-817 Series
Seiko Instruments Inc.
15
Selection of Output Capacitor (C
L
)
To stabilize operation against variation in output load, a capacitor (C
L
) must be mounted between VOUT
and VSS in the S-817 series because the phase is compensated with the help of the internal phase
compensation circuit and the ESR of the output capacitor.
When selecting a ceramic or an OS capacitor, capacitance should be 0.1
μ
F or more, and when selecting a
tantalum or an aluminum electrolytic capacitor, capacitance should be 0.1
μ
F or more and ESR 30
or
less.
When an aluminum electrolytic capacitor is used attention should be especially paid to since the ESR of the
aluminum electrolytic capacitor increases at low temperature and possibility of oscillation becomes large.
Sufficient evaluation including temperature characteristics is indispensable. Overshoot and undershoot
characteristics differ depending upon the type of the output capacitor. Refer to C
L
dependencies in “
Reference Data
1. Transient Response Characteristics
”.
Application Circuits
1. Output Current Boosting Circuit
R
2
R
1
Tr1
GND
VOUT
VIN
VSS
V
IN
V
OUT
C
L
S-817
series
C
IN
Figure 14
As shown in
Figure 14
, the output current can be boosted by externally attaching a PNP transistor. The
base current of the PNP transistor is controlled so that output voltage (V
OUT
) goes the voltage specified
in the S-817 Series when base-emitter voltage (V
BE
) necessary to turn on the PNP transistor is obtained
between input voltage (V
IN
) and S-817 Series power source pin (VIN).
The following are tips and hints for selecting and ensuring optimum use of external parts
PNP transistor (Tr1):
1. Set h
FE
to approx. 100 to 400.
2. Confirm that no problem occurs due to power dissipation under normal operation conditions.
Resistor (R
1
):
Generally set R
1
to 1 k
÷
V
OUT (S)
(the voltage specified in the S-817 Series) or more.
Output capacitor (C
L
):
Output capacitor (C
L
) is effective in minimizing output fluctuation at powering on or due to power
or load fluctuation, but oscillation might occur. Always connect resistor R2 in series to output
capacitor C
L
.
Resistor (R
2
): Set R
2
to 2
×
V
OUT(S)
or more.
DO NOT attach a capacitor between the S-817 Series power source (V
IN
) and GND pins or
between base and emitter of the PNP transistor to avoid oscillation.
To improve transient response characteristics of the output current boosting circuit shown in
Figure 14
, check that no problem occurs due to output fluctuation at powering on or due to
power or load fluctuation under normal operating conditions.
Pay attention to the short current limit circuit incorporated into the S-817 Series because it does
not function as a shortcircuiting protection circuit for this boosting circuit.
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S-817 制造商:SII 制造商全稱(chēng):Seiko Instruments Inc 功能描述:SUPER-SMALL PACKAGE CMOS VOLTAGE REGULATOR
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S8171AV34 制造商: 功能描述: 制造商:undefined 功能描述:
S-817A11ANB-CUA-T2 功能描述:低壓差穩(wěn)壓器 - LDO 1.1V 1.2uA 2.0% RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類(lèi)型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20
S-817A11ANB-CUAT2G 功能描述:低壓差穩(wěn)壓器 - LDO 1.1V 1.2uA 2.0% RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類(lèi)型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20
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