LP2985AIM5-3.1/NOPB
更新时间:2024-09-18 18:37:11
品牌:NSC
描述:IC VREG 3.1 V FIXED POSITIVE LDO REGULATOR, 0.575 V DROPOUT, PDSO5, SOT-23, 5 PIN, Fixed Positive Single Output LDO Regulator
LP2985AIM5-3.1/NOPB 概述
IC VREG 3.1 V FIXED POSITIVE LDO REGULATOR, 0.575 V DROPOUT, PDSO5, SOT-23, 5 PIN, Fixed Positive Single Output LDO Regulator 线性稳压器IC
LP2985AIM5-3.1/NOPB 规格参数
是否Rohs认证: | 符合 | 生命周期: | Transferred |
包装说明: | LSSOP, TSOP5/6,.11,37 | Reach Compliance Code: | compliant |
ECCN代码: | EAR99 | HTS代码: | 8542.39.00.01 |
风险等级: | 6.87 | 可调性: | FIXED |
最大回动电压 1: | 0.575 V | 标称回动电压 1: | 0.28 V |
最大绝对输入电压: | 16 V | 最大输入电压: | 16 V |
最小输入电压: | 4.1 V | JESD-30 代码: | R-PDSO-G5 |
JESD-609代码: | e3 | 长度: | 2.92 mm |
最大电网调整率: | 0.0118% | 湿度敏感等级: | 1 |
功能数量: | 1 | 输出次数: | 1 |
端子数量: | 5 | 工作温度TJ-Max: | 125 °C |
工作温度TJ-Min: | -40 °C | 最大输出电流 1: | 0.15 A |
最大输出电压 1: | 3.2085 V | 最小输出电压 1: | 2.9915 V |
标称输出电压 1: | 3.1 V | 封装主体材料: | PLASTIC/EPOXY |
封装代码: | LSSOP | 封装等效代码: | TSOP5/6,.11,37 |
封装形状: | RECTANGULAR | 封装形式: | SMALL OUTLINE, LOW PROFILE, SHRINK PITCH |
包装方法: | TAPE AND REEL | 峰值回流温度(摄氏度): | 260 |
认证状态: | Not Qualified | 调节器类型: | FIXED POSITIVE SINGLE OUTPUT LDO REGULATOR |
座面最大高度: | 1.22 mm | 子类别: | Other Regulators |
表面贴装: | YES | 技术: | BIPOLAR |
端子面层: | Matte Tin (Sn) | 端子形式: | GULL WING |
端子节距: | 0.953 mm | 端子位置: | DUAL |
处于峰值回流温度下的最长时间: | 40 | 最大电压容差: | 3.5% |
宽度: | 1.6 mm | Base Number Matches: | 1 |
LP2985AIM5-3.1/NOPB 数据手册
通过下载LP2985AIM5-3.1/NOPB数据手册来全面了解它。这个PDF文档包含了所有必要的细节,如产品概述、功能特性、引脚定义、引脚排列图等信息。
PDF下载November 25, 2009
LP2985
Micropower 150 mA Low-Noise Ultra Low-Dropout
Regulator in SOT-23 and micro SMD Packages
Designed for Use with Very Low ESR Output Capacitors
General Description
Features
The LP2985 is a 150 mA, fixed-output voltage regulator de-
signed to provide ultra low-dropout and low noise in battery
powered applications.
Ultra low dropout voltage
■
■
■
■
■
■
■
■
Guaranteed 150 mA output current
Smallest possible size (SOT-23, micro SMD package)
Using an optimized VIP® (Vertically Integrated PNP) process,
the LP2985 delivers unequalled performance in all specifica-
tions critical to battery-powered designs:
Requires minimum external components
Stable with low-ESR output capacitor
<1 µA quiescent current when shut down
Dropout Voltage: Typically 300 mV @ 150 mA load, and
7 mV @ 1 mA load.
Low ground pin current at all loads
Output voltage accuracy 1% (A Grade)
Ground Pin Current: Typically 850 µA @ 150 mA load, and
75 µA @ 1 mA load.
High peak current capability
■
■
Enhanced Stability: The LP2985 is stable with output ca-
pacitor ESR as low as 5 mΩ, which allows the use of ceramic
capacitors on the output.
Wide supply voltage range (16V max)
Low ZOUT: 0.3Ω typical (10 Hz to 1 MHz)
Overtemperature/overcurrent protection
−40°C to +125°C junction temperature range
Custom voltages available
■
■
■
■
Sleep Mode: Less than 1 µA quiescent current when ON/OFF
pin is pulled low.
Smallest Possible Size: SOT-23 and micro SMD packages
use absolute minimum board space.
Applications
Precision Output: 1% tolerance output voltages available (A
grade).
Cellular Phone
■
■
■
Low Noise: By adding a 10 nF bypass capacitor, output noise
can be reduced to 30 µV (typical).
Palmtop/Laptop Computer
Personal Digital Assistant (PDA)
Multiple voltage options, from 2.5V to 5.0V, are available as
standard products. Consult factory for custom voltages.
Camcorder, Personal Stereo, Camera
■
Block Diagram
10014001
VIP® is a registered trademark of National Semiconductor Corporation.
© 2009 National Semiconductor Corporation
100140
www.national.com
Basic Application Circuit
10014002
ꢀꢀ*ON/OFF input must be actively terminated. Tie to VIN if this function is not to be used.
ꢀ**Minimum capacitance is shown to ensure stability (may be increased without limit). Ceramic capacitor required for output (see Application Hints).
***Reduces output noise (may be omitted if application is not noise critical). Use ceramic or film type with very low leakage current (see Application Hints).
Connection Diagrams
SOT-23, 5-Lead Small Outline Package (M5)
micro SMD, 5 Bump Package
10014003
Top View
See NS Package Number MF05A
10014046
Note: The actual physical placement of the package marking will vary from part
to part. Package marking contains date code and lot traceability information, and
will vary considerably. Package marking does not correlate to device type.
Top View
See NS Package Numbers TPA05 and TLA05
Pin Descriptions
Name
Pin Number
micro SMD
Function
SOT-23
VIN
1
2
3
4
5
C3
A1
A3
B2
C1
Input Voltage
GND
Common Ground (device substrate)
Logic high enable input
ON/OFF
BYPASS
VOUT
Bypass capacitor for low noise operation
Regulated output voltage
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2
Ordering Information
TABLE 1. Package Marking and Ordering Information
Output Voltage
Grade
Order Information
Package Marking
Supplied as:
(V)
For output voltages ≤ 2.0V, refer to LP2985LV datasheet.
SOT-23, 5-Lead Small Outline Package (M5)
LP2985AIM-2.5
LAUA
LAUA
LAUB
LAUB
LCEA
LCEA
LALA
LALA
LALB
LALB
L0KA
L0KA
L0KB
L0KB
LAXA
LAXA
LAXB
LAXB
L0OA
L0OA
L0OB
L0OB
L0PA
L0PA
L0PB
L0PB
L0QB
L0RA
L0RA
L0RB
L0RB
LAIA
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
1000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
A
LP2985AIM5X-2.5
2.5
LP2985IM5-2.5
STD
LP2985IM5X-2.5
LP2985AIM5-2.6
2.6
2.7
A
A
LP2985AIM5X-2.6
LP2985AIM5-2.7
LP2985AIM5X-2.7
LP2985IM5-2.7
LP2985IM5X-2.7
LP2985AIM5-2.8
LP2985AIM5X-2.8
LP2985IM5-2.8
LP2985IM5X-2.8
LP2985AIM5-2.9
LP2985AIM5X-2.9
LP2985IM5-2.9
LP2985IM5X-2.9
LP2985AIM5-3.0
LP2985AIM5X-3.0
LP2985IM5-3.0
LP2985IM5X-3.0
LP2985AIM5-3.1
LP2985AIM5X-3.1
LP2985IM5-3.1
LP2985IM5X-3.1
LP2985IM5-3.2
LP2985AIM5-3.3
LP2985AIM5X-3.3
LP2985IM5-3.3
LP2985IM5X-3.3
LP2985AIM5-3.5
LP2985IM5-3.5
LP2985AIM5-3.6
LP2985AIM5X-3.6
LP2985IM5-3.6
LP2985IM5X-3.6
LP2985AIM5-3.8
LP2985AIM5X-3.8
LP2985IM5-3.8
LP2985IM5X-3.8
STD
A
2.8
2.9
3.0
STD
A
STD
A
STD
A
3.1
3.2
3.3
STD
STD
A
STD
A
3.5
3.6
STD
LAIB
L0SA
L0SA
L0SB
L0SB
L0YA
L0YA
L0YB
L0YB
A
STD
A
3.8
STD
3
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Output Voltage
(V)
Grade
A
Order Information
Package Marking
Supplied as:
LP2985AIM5-4.0
LP2985AIM5X-4.0
LP2985IM5-4.0
LP2985IM5X-4.0
LP2985AIM5-4.5
LP2985AIM5X-4.5
LP2985IM5X-4.5
LP2985IM5-4.5
LP2985AIM5-5.0
LP2985AIM5X-5.0
LP2985IM5-5.0
LP2985IM5X-5.0
LP2985AIM5-5.7
LP2985AIM5X-5.7
LP2985IM5-5.7
LP2985IM5X-5.7
LP2985AIM5-6.1
LP2985AIM5X-6.1
LP2985IM5-6.1
LP2985IM5X-6.1
L0TA
L0TA
L0TB
L0TB
LA7A
LA7A
LA7B
LA7B
L0UA
L0UA
L0UB
L0UB
LKTA
LKTA
LKTB
LKTB
LF6A
LF6A
LF6B
LF6B
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
1000 Units on Tape and Reel
3000 Units on Tape and Reel
4.0
4.5
5.0
5.7
6.1
STD
A
STD
A
STD
A
STD
A
STD
micro SMD, 5 Bump Package (TPA05 - 170 µm ball)
A
LP2985AITPX-2.5
3000 Units on Tape and Reel
250 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
2.5
STD
LP2985ITP-2.5
LP2985AITP-2.6
LP2985AITPX-2.6
LP2985ITP-2.6
LP2985ITPX-2.6
LP2985AITP-2.7
LP2985AITPX-2.7
LP2985ITP-2.7
LP2985ITPX-2.7
LP2985AITP-2.8
LP2985AITPX-2.8
LP2985ITP-2.8
LP2985ITPX-2.8
LP2985AITP-2.9
LP2985AITPX-2.9
LP2985ITP-2.9
LP2985ITPX-2.9
LP2985AITP-3.0
LP2985AITPX-3.0
LP2985ITP-3.0
LP2985ITPX-3.0
LP2985AITP-3.3
LP2985AITPX-3.3
LP2985ITP-3.3
LP2985ITPX-3.3
A
STD
A
2.6
2.7
2.8
2.9
3.0
3.3
STD
A
STD
A
STD
A
STD
A
STD
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Output Voltage
(V)
Grade
A
Order Information
Package Marking
Supplied as:
LP2985AITP-5.0
LP2985AITPX-5.0
LP2985ITP-5.0
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
5.0
STD
LP2985ITPX-5.0
micro SMD, 5 Bump Package (TLA05 - 300 µm ball)
LP2985AITL-3.3
250 Units on Tape and Reel
3000 Units on Tape and Reel
250 Units on Tape and Reel
3000 Units on Tape and Reel
A
LP2985AITLX-3.3
LP2985ITL-3.3
3.3
STD
LP2985ITLX-3.3
5
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Power Dissipation (Note 3)
Input Supply Voltage (Survival)
Input Supply Voltage (Operating)
Shutdown Input Voltage (Survival)
Output Voltage (Survival, (Note 4))
IOUT (Survival)
Internally Limited
−0.3V to +16V
2.5V to +16V
−0.3V to +16V
−0.3V to +9V
Short Circuit
Protected
−0.3V to +16V
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Storage Temperature Range
−65°C to +150°C
Operating Junction Temperature
Range
Lead Temp. (Soldering, 5 sec.)
−40°C to +125°C
260°C
Input-Output Voltage (Survival,
ꢁ(Note 5))
ESD Rating (Note 2)
2 kV
Electrical Characteristics (Note 10)
Limits in standard typeface are for TJ = 25°C. and limits in boldface type apply over the full operating temperature range. Unless
otherwise specified: VIN = VO(NOM) + 1V, IL = 1 mA, CIN = 1 µF, COUT = 4.7 µF, VON/OFF = 2V.
LP2985AI-X.X
LP2985I-X.X
(Note 6)
(Note 6)
Symbol
ΔVO
Parameter
Conditions
IL = 1 mA
Typ
Units
Min
−1.0
−1.5
Max
1.0
Min
−1.5
−2.5
Max
1.5
Output Voltage
Tolerance
1.5
2.5
1 mA ≤ IL ≤ 50 mA
%VNOM
−2.5
2.5
−3.5
3.5
−2.5
2.5
−3.0
3.0
1 mA ≤ IL ≤ 150 mA
VO(NOM)+1V ≤ VIN ≤ 16V
−3.5
3.5
−4.0
4.0
Output Voltage
Line Regulation
0.007
0.014
0.014
%/V
0.032
0.032
VIN–VO
Dropout Voltage
(Note 7)
IL = 0
1
3
5
3
5
IL = 1 mA
IL = 10 mA
IL = 50 mA
IL = 150 mA
IL = 0
7
10
10
15
15
40
60
60
mV
90
90
120
280
65
150
225
350
575
95
150
225
350
575
95
IGND
Ground Pin Current
125
110
170
220
400
600
1000
1500
2500
0.8
2
125
110
170
220
400
600
1000
1500
2500
0.8
2
IL = 1 mA
IL = 10 mA
IL = 50 mA
IL = 150 mA
75
120
350
850
µA
VON/OFF < 0.3V
VON/OFF < 0.15V
0.01
0.05
1.4
VON/OFF
ION/OFF
ON/OFF Input Voltage High = O/P ON
1.6
1.6
V
(Note 8)
Low = O/P OFF
VON/OFF = 0
0.55
0.01
5
0.15
−2
0.15
−2
ON/OFF Input Current
µA
VON/OFF = 5V
15
15
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LP2985AI-X.X
LP2985I-X.X
(Note 6)
(Note 6)
Symbol
Parameter
Output Noise
Conditions
Typ
Units
Min
Max
Min
Max
en
BW = 300 Hz to 50 kHz,
COUT = 10 µF
Voltage (RMS)
30
45
µV
dB
CBYPASS = 10 nF
Ripple Rejection
f = 1 kHz, CBYPASS = 10 nF
COUT = 10 µF
IO(SC)
IO(PK)
Short Circuit Current
Peak Output Current
RL = 0 (Steady State)
400
350
mA
mA
(Note 9)
VOUT ≥ Vo(NOM) −5%
Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating
the device outside of its rated operating conditions.
Note 2: The ESD rating of pins 3 and 4 for the SOT-23 package, or pins 5 and 2 for the micro SMD package, is 1 kV.
Note 3: The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(MAX), the junction-to-ambient thermal resistance, θJ-
A, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperture is calculated using:
Where the value of θJ-A for the SOT-23 package is 220°C/W in a typical PC board mounting and the micro SMD package is 225°C/W. Exceeding the maximum
allowable dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown.
Note 4: For 12V option, output voltage survival: -0.3 to +16V. If used in a dual-supply system where the regulator load is returned to a negative supply, the LP2985
output must be diode-clamped to ground.
Note 5: The output PNP structure contains a diode between the VIN to VOUT terminals that is normally reverse-biased. Reversing the polarity from VIN to VOUT
will turn on this diode.
Note 6: Limits are 100% production tested at 25°C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality
Control (SQC) methods. The limits are used to calculate National's Average Outgoing Quality Level (AOQL).
Note 7: Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV below the value measured with a 1V differential.
Note 8: The ON/OFF input must be properly driven to prevent possible misoperation. For details, refer to Application Hints.
Note 9: The LP2985 has foldback current limiting which allows a high peak current when VOUT > 0.5V, and then reduces the maximum output current as VOUT is
forced to ground (see Typical Performance Characteristics curves).
Note 10: Exposing the micro SMD device to direct sunlight will cause misoperation. See Application Hints for additional information.
7
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Typical Performance Characteristics Unless otherwise specified: CIN = 1µF, COUT = 4.7µF, VIN = VOUT
(NOM) +1, TA = 25°C, ON/OFF pin is tied to VIN.
VOUT vs Temperature
Short-Circuit Current
Ripple Rejection
Short-Circuit Current
10014009
10014008
Short Circuit Current vs Output Voltage
10014010
10014011
Ripple Rejection
10014013
10014014
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Ripple Rejection
Ripple Rejection
Ripple Rejection
Ripple Rejection
Ripple Rejection
Ripple Rejection
10014015
10014017
10014019
10014016
10014018
10014023
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Ripple Rejection
Output Impedance vs Frequency
10014020
10014022
Output Impedance vs Frequency
Output Noise Density
10014024
10014021
Output Noise Density
Ground Pin vs Load Current
10014025
10014026
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Dropout Voltage vs Temperature
Input Current vs Pin
10014027
10014029
GND Pin Current vs Temperature
Instantaneous Short Circuit Current
10014031
10014030
Load Transient Response
Load Transient Response
10014032
10014033
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Load Transient Response
Line Transient Response
Line Transient Response
Line Transient Response
Line Transient Response
Turn-On Time
10014035
10014034
10014036
10014037
10014038
10014039
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Turn-On Time
Turn-On Time
10014041
10014040
Turn-On Time
10014042
13
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Application Hints
EXTERNAL CAPACITORS
capacitors can exhibit large changes in capacitance with tem-
perature (see next section, Capacitor Characteristics).
Like any low-dropout regulator, the LP2985 requires external
capacitors for regulator stability. These capacitors must be
correctly selected for good performance.
The output capacitor must be located not more than 1 cm from
the output pin and returned to a clean analog ground.
Input Capacitor
Noise Bypass Capacitor
An input capacitor whose capacitance is ≥ 1 µF is required
between the LP2985 input and ground (the amount of capac-
itance may be increased without limit).
Connecting a 10 nF capacitor to the Bypass pin significantly
reduces noise on the regulator output. It should be noted that
the capacitor is connected directly to a high-impedance circuit
in the bandgap reference.
This capacitor must be located a distance of not more than 1
cm from the input pin and returned to a clean analog ground.
Any good quality ceramic, tantalum, or film capacitor may be
used at the input.
Because this circuit has only a few microamperes flowing in
it, any significant loading on this node will cause a change in
the regulated output voltage. For this reason, DC leakage
current through the noise bypass capacitor must never ex-
ceed 100 nA, and should be kept as low as possible for best
output voltage accuracy.
Important: Tantalum capacitors can suffer catastrophic fail-
ure due to surge current when connected to a low-impedance
source of power (like a battery or very large capacitor). If a
Tantalum capacitor is used at the input, it must be guaranteed
by the manufacturer to have a surge current rating sufficient
for the application.
The types of capacitors best suited for the noise bypass ca-
pacitor are ceramic and film. High-quality ceramic capacitors
with either NPO or COG dielectric typically have very low
leakage. 10 nF polypropolene and polycarbonate film capac-
itors are available in small surface-mount packages and typ-
ically have extremely low leakage current.
There are no requirements for ESR on the input capacitor, but
tolerance and temperature coefficient must be considered
when selecting the capacitor to ensure the capacitance will
be ≥ 1 µF over the entire operating temperature range.
CAPACITOR CHARACTERISTICS
Output Capacitor
The LP2985 was designed to work with ceramic capacitors
on the output to take advantage of the benefits they offer: for
capacitance values in the 2.2 µF to 4.7 µF range, ceramics
are the least expensive and also have the lowest ESR values
(which makes them best for eliminating high-frequency
noise). The ESR of a typical 2.2 µF ceramic capacitor is in the
range of 10 mΩ to 20 mΩ, which easily meets the ESR limits
required for stability by the LP2985.
The LP2985 is designed specifically to work with ceramic out-
put capacitors, utilizing circuitry which allows the regulator to
be stable across the entire range of output current with an
output capacitor whose ESR is as low as 5 mΩ. It may also
be possible to use Tantalum or film capacitors at the output,
but these are not as attractive for reasons of size and cost
(see next section Capacitor Characteristics).
One disadvantage of ceramic capacitors is that their capaci-
tance can vary with temperature. Most large value ceramic
capacitors (≥ 2.2 µF) are manufactured with the Z5U or Y5V
temperature characteristic, which results in the capacitance
dropping by more than 50% as the temperature goes from 25°
C to 85°C.
The output capacitor must meet the requirement for minimum
amount of capacitance and also have an ESR (equivalent se-
ries resistance) value which is within the stable range. Curves
are provided which show the stable ESR range as a function
of load current (see ESR graph below).
This could cause problems if a 2.2 µF capacitor were used on
the output since it will drop down to approximately 1 µF at high
ambient temperatures (which could cause the LM2985 to os-
cillate). If Z5U or Y5V capacitors are used on the output, a
minimum capacitance value of 4.7 µF must be observed.
A better choice for temperature coefficient in ceramic capac-
itors is X7R, which holds the capacitance within ±15%. Un-
fortunately, the larger values of capacitance are not offered
by all manufacturers in the X7R dielectric.
Tantalum
Tantalum capacitors are less desirable than ceramics for use
as output capacitors because they are more expensive when
comparing equivalent capacitance and voltage ratings in the
1 µF to 4.7 µF range.
Another important consideration is that Tantalum capacitors
have higher ESR values than equivalent size ceramics. This
means that while it may be possible to find a Tantalum ca-
pacitor with an ESR value within the stable range, it would
have to be larger in capacitance (which means bigger and
more costly) than a ceramic capacitor with the same ESR
value.
10014007
Important: The output capacitor must maintain its ESR within
the stable region over the full operating temperature range of
the application to assure stability.
The LP2985 requires a minimum of 2.2 µF on the output (out-
put capacitor size can be increased without limit).
It is important to remember that capacitor tolerance and vari-
ation with temperature must be taken into consideration when
selecting an output capacitor so that the minimum required
amount of output capacitance is provided over the full oper-
ating temperature range. It should be noted that ceramic
It should also be noted that the ESR of a typical Tantalum will
increase about 2:1 as the temperature goes from 25°C down
to −40°C, so some guard band must be allowed.
www.national.com
14
On/Off Input Operation
VIN to VOUT (cathode on VIN, anode on VOUT), to limit the re-
verse voltage across the LP2985 to 0.3V (see Absolute Max-
imum Ratings).
The LP2985 is shut off by driving the ON/OFF input low, and
turned on by pulling it high. If this feature is not to be used,
the ON/OFF input should be tied to VIN to keep the regulator
output on at all times.
To assure proper operation, the signal source used to drive
the ON/OFF input must be able to swing above and below the
specified turn-on/turn-off voltage thresholds listed in the Elec-
trical Characteristics section under VON/OFF. To prevent mis-
operation, the turn-on (and turn-off) voltage signals applied to
the ON/OFF input must have
a slew rate which is
≥ 40 mV/µs.
Caution: the regulator output voltage can not be guaranteed
if a slow-moving AC (or DC) signal is applied that is in the
range between the specified turn-on and turn-off voltages list-
ed under the electrical specification VON/OFF (see Electrical
Characteristics).
10014055
REVERSE INPUT-OUTPUT VOLTAGE
FIGURE 2. Reverse Current Protection
The PNP power transistor used as the pass element in the
LP2985 has an inherent diode connected between the regu-
lator output and input. During normal operation (where the
input voltage is higher than the output) this diode is reverse-
biased.
MICRO SMD MOUNTING
The micro SMD package requires specific mounting tech-
niques which are detailed in National Semiconductor Appli-
cation Note # 1112. Referring to the section Surface Mount
Technology (SMT) Assembly Considerations, it should be
noted that the pad style which must be used with the 5-pin
package is the NSMD (non-solder mask defined) type.
For best results during assembly, alignment ordinals on the
PC board may be used to facilitate placement of the micro
SMD device.
MICRO SMD LIGHT SENSITIVITY
Exposing the micro SMD device to direct sunlight will cause
misoperation of the device. Light sources such as Halogen
lamps can also affect electrical performance if brought near
to the device.
10014054
FIGURE 1. Reverse Current Path
The wavelenghts which have the most detrimental effect are
reds and infra-reds, which means that the fluorescent lighting
used inside most buildings has very little effect on perfor-
mance. A micro SMD test board was brought to within 1 cm
of a fluorescent desk lamp and the effect on the regulated
output voltage was negligible, showing a deviation of less
than 0.1% from nominal.
However, if the output is pulled above the input, this diode will
turn ON and current will flow into the regulator output. In such
cases, a parasitic SCR can latch which will allow a high cur-
rent to flow into VIN (and out the ground pin), which can
damage the part.
In any application where the output may be pulled above the
input, an external Schottky diode must be connected from
15
www.national.com
Physical Dimensions inches (millimeters) unless otherwise noted
SOT-23, 5-Lead Small Outline Package (M5)
NS Package Number MF05A.
www.national.com
16
NOTES: UNLESS OTHERWISE SPECIFIED
1. EPOXY COATING
2. 63Sn/37Pb EUTECTIC BUMP
3. RECOMMEND NON-SOLDER MASK DEFINED LANDING PAD.
4. PIN 1 IS ESTABLISHED BY LOWER LEFT CORNER WITH RESPECT TO TEXT ORIENTATION. REMAINING PINS ARE NUMBERED COUNTER CLOCK-
WISE.
5. XXX IN DRAWING NUMBER REPRESENTS PACKAGE SIZE VARIATION WHERE X1 IS PACKAGE WIDTH, X2 IS PACKAGE LENGTH AND X3 IS PACK-
AGE HEIGHT.
6.NO JEDEC REGISTRATION AS OF AUG.1999.
micro SMD, 5 Bump, Package (TPA05 - 170 µm ball)
NS Package Number TPA05
The dimensions for X1, X2 and X3 are as given:
X1 = 0.930 +/− 0.030mm
X2 = 1.107 +/− 0.030mm
X3 = 0.500 +/− 0.075mm
17
www.national.com
NOTES: UNLESS OTHERWISE SPECIFIED
1. EPOXY COATING
2. 63Sn/37Pb EUTECTIC BUMP
3. RECOMMEND NON-SOLDER MASK DEFINED LANDING PAD.
4. PIN 1 IS ESTABLISHED BY LOWER LEFT CORNER WITH RESPECT TO TEXT ORIENTATION. REMAINING PINS ARE NUMBERED COUNTER CLOCK-
WISE.
5. XXX IN DRAWING NUMBER REPRESENTS PACKAGE SIZE VARIATION WHERE X1 IS PACKAGE WIDTH, X2 IS PACKAGE LENGTH AND X3 IS PACK-
AGE HEIGHT.
6.NO JEDEC REGISTRATION AS OF AUG.1999.
micro SMD, 5 Bump, Package (TLA05 - 300 µm ball)
NS Package Number TLA05
The dimensions for X1, X2 and X3 are as given:
X1 = 1.031 +/− 0.030mm
X2 = 1.412 +/− 0.030mm
X3 = 0.600 +/− 0.075mm
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18
Notes
19
www.national.com
Notes
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LP2985AIM5-3.1/NOPB 替代型号
型号 | 制造商 | 描述 | 替代类型 | 文档 |
LD2985BM50R | STMICROELECTRONICS | VERY LOW DROP AND LOW NOISE VOLTAGE REGULATOR LOW ESR CAP. COMPATIBLE, WITH INHIBIT FUNCTI | 功能相似 | |
LD2985BM18R | STMICROELECTRONICS | VERY LOW DROP AND LOW NOISE VOLTAGE REGULATOR LOW ESR CAP. COMPATIBLE, WITH INHIBIT FUNCTI | 功能相似 | |
LD2985BM30R | STMICROELECTRONICS | VERY LOW DROP AND LOW NOISE VOLTAGE REGULATOR LOW ESR CAP. COMPATIBLE, WITH INHIBIT FUNCTI | 功能相似 |
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LP2985AIM5-3.5/NOPB | TI | 3.5V FIXED POSITIVE LDO REGULATOR, 0.575V DROPOUT, PDSO5, SOT-23, 5 PIN | 获取价格 |
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