数据搜索系统,热门电子元器件搜索
  Chinese  ▼
ALLDATASHEETCN.COM

X  

ADP667 数据表(PDF) 5 Page - Analog Devices

部件名 ADP667
功能描述  Low-Dropout Linear Voltage Regulator
Download  12 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
制造商  AD [Analog Devices]
网页  http://www.analog.com
标志 AD - Analog Devices

ADP667 数据表(HTML) 5 Page - Analog Devices

  ADP667_15 Datasheet HTML 1Page - Analog Devices ADP667_15 Datasheet HTML 2Page - Analog Devices ADP667_15 Datasheet HTML 3Page - Analog Devices ADP667_15 Datasheet HTML 4Page - Analog Devices ADP667_15 Datasheet HTML 5Page - Analog Devices ADP667_15 Datasheet HTML 6Page - Analog Devices ADP667_15 Datasheet HTML 7Page - Analog Devices ADP667_15 Datasheet HTML 8Page - Analog Devices ADP667_15 Datasheet HTML 9Page - Analog Devices Next Button
Zoom Inzoom in Zoom Outzoom out
 5 / 12 page
background image
ADP667
REV. 0
–5–
Dropout Detector
The ADP667 features an extremely low dropout voltage making
it suitable for low voltage systems where headroom is limited. A
dropout detector is also provided. The dropout detector output,
DD, changes as the dropout voltage approaches its limit. This is
useful for warning that regulation can no longer be maintained.
The dropout detector output is an open collector output from a
PNP transistor. Under normal operating conditions with the in-
put voltage more than 300 mV above the output, the PNP tran-
sistor is off and no current flows out the DD pin. As the voltage
differential reduces to less than 300 mV, the transistor switches
on and current is sourced. This condition indicates that regulation
can no longer be maintained. Please refer to Figure 10 in the
“Typical Performance Characteristics.” The current output can
be translated into a voltage output by connecting a resistor from
DD to GND. A resistor value of 100 k
Ω is suitable. A digital
status signal can be obtained using a comparator. The on-chip
comparator LBI may be used if it is not being used to monitor a
battery voltage. This is illustrated in Figure 5.
+
C1
10µF
IN
OUT
LBO
ADP667
+5V
OUTPUT
R2
10k
LBI
GND
SET
SHDN
DROPOUT
STATUS
OUTPUT
DD
VIN
R1
100k
+
Figure 5. Dropout Status Output
Output Capacitor Selection
An output capacitor is required on the ADP667 to maintain
stability and also to improve the load transient response. Ca-
pacitor values from 10
µF upwards are suitable. All specifica-
tions are tested and guaranteed with 10
µF. Capacitors larger
than 10
µF will further improve the dynamic transient response
characteristics of the regulator. Tantalum or aluminum electro-
lytics are suitable for most applications. For temperatures below
about –25
°C, solid tantalums should be used as many alumi-
num electrolytes freeze at this temperature.
Quiescent Current Considerations
The ADP667 uses a PNP output stage to achieve low dropout
voltages combined with high output current capability. Under
normal regulating conditions the quiescent current is extremely
low. However if the input voltage drops so that it is below the
desired output voltage, the quiescent current increases consider-
ably. This happens because regulation can no longer be main-
tained and large base current flows in the PNP output transistor
in an attempt to hold it fully on. For minimum quiescent cur-
rent, it is therefore important that the input voltage is main-
tained higher than the desired output level. If the device is being
powered using a battery that can discharge down below the rec-
ommended level, there are a couple of techniques that can be
applied to reduce the quiescent current, but at the expense of
dropout voltage. The first of these is illustrated in Figure 6. By
connecting DD to SHDN the regulator is partially disabled with
input voltages below the desired output voltage and therefore
the quiescent current is reduced considerably.
+
C1
10µF
IN
OUT
ADP667
+5V
OUTPUT
GND
SET
SHDN
DD
VIN
R1
47k
+
C2
0.1µF
Figure 6. IQ Reduction 1
Another technique for reducing the quiescent current near drop-
out is illustrated in Figure 7. The DD output is used to modify
the output voltage so that as VIN drops, the desired output volt-
age setpoint also drops. This technique only works when exter-
nal resistors are used to set the output voltage. With VIN greater
than VOUT, DD has no effect. As VIN reduces and dropout is
reached, the DD output starts sourcing current into the SET
input through R3. This increases the SET voltage so that the
regulator feedback loop does not drive the internal PNP transis-
tor as hard as it otherwise would. As the input voltage continues
to decrease, more current is sourced, thereby reducing the PNP
drive even further. The advantage of this scheme is that it main-
tains a low quiescent current down to very low values of VIN at
which point the batteries are well outside their useful operating
range. The output voltage tracks the input voltage minus the
dropout. The SHDN function is also unaffected and may be
used normally if desired.
+
C1
10µF
IN
OUT
ADP667
+5V
OUTPUT
GND
SET
SHDN
DD
R1
332k
R2
1M
R3
1M
+
VIN
Figure 7. IQ Reduction 2
A


类似零件编号 - ADP667_15

制造商部件名数据表功能描述
logo
Analog Devices
ADP667AN AD-ADP667AN Datasheet
135Kb / 8P
   5 V Fixed, Adjustable Low-Dropout Linear Voltage Regulator
REV. 0
ADP667AN AD-ADP667AN Datasheet
132Kb / 8P
   5 V Fixed, Adjustable Low-Dropout Linear Voltage Regulator
REV. 0
ADP667AN AD-ADP667AN Datasheet
116Kb / 8P
   5 V Fixed, Adjustable Low-Dropout Linear Voltage Regulator
REV. 0
ADP667ANZ AD-ADP667ANZ Datasheet
116Kb / 8P
   5 V Fixed, Adjustable Low-Dropout Linear Voltage Regulator
REV. 0
ADP667AR AD-ADP667AR Datasheet
135Kb / 8P
   5 V Fixed, Adjustable Low-Dropout Linear Voltage Regulator
REV. 0
More results

类似说明 - ADP667_15

制造商部件名数据表功能描述
logo
Infineon Technologies A...
TLE42764 INFINEON-TLE42764_11 Datasheet
1Mb / 20P
   Low Dropout Linear Voltage Regulator
Rev. 1.2, 2011-02-15
TLE42344G INFINEON-TLE42344G Datasheet
1Mb / 13P
   Low Dropout Linear Voltage Regulator
Rev. 1.0, 2010-02-08
TLE42744 INFINEON-TLE42744 Datasheet
438Kb / 18P
   Low Dropout Linear Voltage Regulator
Rev. 1.1, January 2010
IFX2931 INFINEON-IFX2931 Datasheet
1Mb / 15P
   Low Dropout Linear Voltage Regulator
Rev. 1.12, 2010-02-23
TLS850B0TBV33 INFINEON-TLS850B0TBV33 Datasheet
901Kb / 23P
   Low dropout linear voltage regulator
Rev. 1.00 2017-09-12
TLS850F1TAV50 INFINEON-TLS850F1TAV50 Datasheet
1Mb / 35P
   Low Dropout Linear Voltage Regulator
Rev. 1.0, 2016-02-04
TLS715B0 INFINEON-TLS715B0_15 Datasheet
1Mb / 20P
   Low Dropout Linear Voltage Regulator
Rev. 1.0, 2015-03-12
TLF2931 INFINEON-TLF2931 Datasheet
1Mb / 15P
   Low Dropout Linear Voltage Regulator
Rev. 1.0, 2010-10-06
TLS715B0EJV50 INFINEON-TLS715B0EJV50 Datasheet
1Mb / 22P
   Low Dropout Linear Voltage Regulator
Rev. 1.0, 2015-04-02
TLS850F2TAV50 INFINEON-TLS850F2TAV50 Datasheet
1Mb / 35P
   Low Dropout Linear Voltage Regulator
Rev. 1.0 2018-09-06
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12


数据表 下载

Go To PDF Page


链接网址




隐私政策
ALLDATASHEETCN.COM
ALLDATASHEET是否为您带来帮助?  [ DONATE ] 

关于 Alldatasheet   |   广告服务   |   联系我们   |   隐私政策   |   链接交换   |   制造商名单
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com