LX8940IP-TR [MICROSEMI]
5V Low Dropout Regulator; 5V低压降稳压器
| 型号： | LX8940IP-TR |
| 厂家： | 
Microsemi |
| 描述： | 5V Low Dropout Regulator |
| 文件： | 总6页 (文件大小：207K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LX8940
®
5V Low Dropout Regulator
TM
PRODUCTION DATA SHEET
KEY FEATURES
DESCRIPTION
2% Internally Trimmed Output
Output Current In Excess Of
1A
Input-Output Differential Less
Than 0.4V At 1A
Reverse Battery Protection
60V Load Dump Protection
-50V Reverse Transient
Protection
Short Circuit Protection
Internal Thermal Overload
Protection
The LX8940 is a 5V, low dropout, case supplies require a low input-output
low quiescent current regulator rated
for 1A of output current. It can
regulate with as low as 0.4V
headroom between the input and
output voltages, thus minimizing
power dissipation. In addition, it can
be used in applications where worst
differential to maintain regulation. This
feature makes it ideal for computer
monitors that have to comply with
energy-efficient / "Green PC" programs,
where the input voltage drops to only a
few tenths of a volt above the output
when power supply enters sleep-mode
operation.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
Available In 3-Lead Plastic TO-
220
PRODUCT HIGHLIGHT
Drops In Most lM2940 Sockets
LX8940
APPLICATIONS
5.3V
5V / 100mA
VIN
OUT
Small Headroom Battery
Applications
High Efficiency Linear
Regulators
0.1µF
10µF
GND
Post Regulators For Switching
Power Supplies
Green PC Monitor Applications
Dropout Voltage vs. Output
Current v.s Temperature
Load Transient Response
600
TA = 25°C CO = 47µF Electrolytic
CIN = 1µF
VIN = 5.3V
500
400
5.00V
4.98V
125°C
25°C
300
200
100
0
100mA
0mA
-40°C
100
500
1000
Time (20µS / Div.)
Output Current (mA)
PACKAGE ORDER INFO
Plastic TO-220
3-Pin
P
TA (°C)
RoHS Compliant / Pb-free
Transition DC: 0543
0 to 125
-40 to 125
LX8940CP
LX8940IP
Note: Available in Tape & Reel. Append the letters “TR” to the part
number. (i.e. LX8940IP-TR)
Copyright © 2000
Rev. 1.3a, 2005-11-18
Microsemi
Page 1
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8940
®
5V Low Dropout Regulator
TM
PRODUCTION DATA SHEET
ABSOLUTE MAXIMUM RATINGS
PACKAGE PIN OUT
Input Voltage (VIN)......................................................................................... -15V to 26V
Maximum Operating Junction Temperature .............................................................. 150°C
Storage Temperature Range.........................................................................-65°C to 150°C
Peak Package Solder Reflow Temp. (40 seconds max. exposure) ................. 260°C (+0,-5)
TAB is GND
3
Output
GND
2
1
Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to
Ground. Currents are positive into, negative out of specified terminal. Pin numbers refer to
DIL packages only
Input
P PACKAGE
(Top View)
RoHS / Pb-free 100% matte Tin Lead Finish
THERMAL DATA
Plastic TO-220 3-Pin
P
THERMAL RESISTANCE-JUNCTION TO TAB, θJT
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA
3.0°C/W
60°C/W
Junction Temperature Calculation: TJ = TA + (PD x θJA).
The θJA numbers are guidelines for the thermal performance of the device/pc-board system. All of the
above assume no ambient airflow.
RECOMMENDED OPERATING CONDITIONS
LX8940
Typ
Parameter
Symbol
Units
Min
Note 2
5
Max
26
1000
60
Input Voltage
VIN
V
mA
V
µF
µF
Load Current (with adequate heatsinking)
Maximum Line Transient (Load Dump), VO < 5.5V
Input Capacitor (VIN to GND)
0.1
10
Output Capacitor with ESR of 10Ω max., (VOUT to GND & VSB to GND)
Note 2: VIN(MIN) = 1.2∆V(MAX) See Dropout Voltage Maximum Limit.
Copyright © 2000
Rev. 1.3a, 2005-11-18
Microsemi
Page 2
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8940
®
5V Low Dropout Regulator
TM
PRODUCTION DATA SHEET
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, the following specifications apply over the operating ambient temperature -40°C to +125°C for the LX8940IP
and 0°C to +125°C for LX8940CP; VIN = 10V, IO = 1A, COUT = 22µF, and for DC characteristics only. Low duty cycle pulse testing
techniques are used which maintains junction and case temperatures equal to the ambient temperature.)
LX8940
Typ
Parameter
Symbol
Test Conditions
Units
Min
Max
SECTION HEADER
Output Voltage
Line Regulation
Load Regulation
Output Impedance (Note 3)
`
VO
∆VOI
∆VOL
rO
IO = 0A, TA = 25°C
7V < VIN < 26, IO =5mA
50mA < IO < 1A
100mADC and 20mARMS, fO = 120Hz
IO < 5mA, 7 < VIN < 26V
IO = 500mA
4.85
5
1
10
200
3
30
115
150
5.15
50
50
V
mV
mV
mΩ
mA
mA
15
50
180
Quiescent Current
IQ
IO = 1000mA
10Hz – 100kHz, IO = 5mA
mA
Output Noise Voltage (Note 3)
Long Term Stability (Note 3)
Ripple Rejection (Note 3)
VORMS
µVRMS
mV /
1000hr
dB
mV
mV
20
RR
fO = 120Hz, 1VRMS, IO = 100mA
IO = 100mA
IO = 500mA
IO = 1A
VIN = 26V
66
150
275
400
1.2
300
500
800
Dropout Voltage
∆V
mV
A
Current Limit
ICL
1
Maximum Operational Input
Voltage
Maximum Line Transient
VIN(MAX)
VIN(TR)
26
31
60
V
V
RO = 100Ω, T < 100mS
Note 3: These parameters, although guaranteed, are not tested in production.
SIMPLIFIED BLOCK DIAGRAM
Input
* Required if regulator is located far from power supply filter
Voltage
C1
0.1µF
Input
1
LX8940
Output
Output
2
Voltage
C2
10µF
Overvoltage
Thermal
Shutdown
+
_
GND
Regulator
Bias
3
1.23V
Reference
Figure 1 – Simplified Block Diagram
Copyright © 2000
Rev. 1.3a, 2005-11-18
Microsemi
Integrated Products Division
Page 3
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8940
®
5V Low Dropout Regulator
TM
PRODUCTION DATA SHEET
APPLICATION NOTE
The advantages of using a low-dropout regulator such as
the LX8940 is the need for less “headroom” for full
regulation, and the inherent reverse polarity protection
provided by the PNP output device. A typical NPN
regulator design requires an input to output differential of
approximately two volts minimum. This is due to the 2Vbe
+ Vcesat of the NPN Darlington used in the output, coupled
with the voltage drop across the current limit resistor. In
contrast, the “PNP Regulator” uses a single series pass
transistor with its single Vcesat, thus the lower input to
output voltage differential or dropout voltage. In some
applications the regulator output voltage is used not only as
a power supply but also as a voltage reference for control
systems. In such cases not just the temperature stability of
the output is important but also the initial accuracy.
LX8940 fills this need as the internal bandgap reference is
trimmed allowing a typical output voltage tolerance of
±1%.
capacitor. Capacitor ESR will vary by manufacturer.
Consequently, some evaluation may be required to
determine the minimum value of the output capacitors.
Generally worst case occurs at the maximum load and
minimum ambient temperature. The size of the output
capacitor can be increased to any value above the
minimum. One possible advantage of this would be to
maintain the output voltage during brief periods of
negative input transients The output capacitors chosen
should be rated for the full range of ambient temperature
over which the circuit will be exposed and expected to
operate. For example, many aluminum type electrolytic
capacitors change values at cold temperatures. The
effective capacitance is reduced and regulator stability is
affected. Tantalum capacitors are a good choice for these
types of environments.
OUTPUT PROTECTION
The output features fault protection against over voltage as
well as a thermal shutdown feature. If the input voltage
rises above 33V (load dump), the output shuts down
automatically. The internal circuitry is thus protected and
the IC is able to survive higher voltage transients than
might otherwise be expected. The thermal shutdown output
effectively guards against overheating of the die and
protects the device from being damaged.
EXTERNAL CAPACITORS
To stabilize the outputs and prevent oscillation (perhaps
by many volts) external capacitors are required. The
minimum recommended value for the output capacitors is
10μF, although the actual size and type will likely vary
according to the particular application, e.g., operating
temperature range and load. Another consideration is the
effective series resistance (ESR) of the
Copyright © 2000
Rev. 1.3a, 2005-11-18
Microsemi
Page 4
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8940
®
5V Low Dropout Regulator
TM
PRODUCTION DATA SHEET
PACKAGE DIMENSIONS
3-Pin Plastic TO-220
P
B
S
MILLIMETERS
INCHES
Dim
MIN
14.22
9.65
3.56
0.51
3.53
MAX
15.88
10.67
4.83
1.14
4.09
MIN
MAX
F
T
Q
A
B
C
D
F
0.560
0.380
0.140
0.020
0.139
0.625
0.420
0.190
0.045
0.161
U
A
G
H
J
K
L
2.54 BSC
0.100 BSC
6.35
1.14
0.250
0.045
0.580
0.050
C
0.30
12.70
1.14
0.012
0.500
0.045
1
2
3
14.73
R
H
1.27
N
Q
R
S
T
5.08 TYP
0.200 TYP
2.54
2.03
1.14
5.84
0.508
3.05
2.92
1.40
6.86
1.14
0.100
0.080
0.045
0.230
0.020
0.120
0.115
0.055
0.270
0.045
K
D
U
Note:
L
J
1. Dimensions do not include mold flash or protrusions;
these shall not exceed 0.155mm(.006”) on any side.
Lead dimension shall not include solder coverage.
G
N
Copyright © 2000
Rev. 1.3a, 2005-11-18
Microsemi
Page 5
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8940
®
5V Low Dropout Regulator
TM
PRODUCTION DATA SHEET
NOTES
PRODUCTION DATA – Information contained in this document is proprietary to
Microsemi and is current as of publication date. This document may not be modified in
any way without the express written consent of Microsemi. Product processing does not
necessarily include testing of all parameters. Microsemi reserves the right to change the
configuration and performance of the product and to discontinue product at any time.
Copyright © 2000
Rev. 1.3a, 2005-11-18
Microsemi
Integrated Products Division
Page 6
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
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