LP2985-36D [ETC]
Analog IC ; 模拟IC\n
ETC 
INTEGRATED CIRCUITS
LP2985-XX
Micropower 150 mA low noise,
low dropout linear regulator
Product data
2001 Oct 03
File under Integrated Circuits, Standard Analog
Philips
Semiconductors
Philips Semiconductors
Product data
Micropower 150 mA low noise,
low dropout linear regulator
LP2985-XX
GENERAL DESCRIPTION
The LP2985-XX is a 150 mA, fixed output voltage regulator designed
to provide very low dropout and low noise in battery powered and
portable applications. The output voltage is preset to 1.8, 2.8, 3.0,
3.3, 3.6, or 5.0 V.
Designed with an optimized PNP process, the LP2985-XX achieves
unequalled performance in all specifications critical to
battery-powered designs such as low supply-current, low dropout
voltage, low power consumption, small size, fast dynamic response
to line and load, precision output, etc. This regulator consists of an
internal voltage reference, an error amplifier, a driver with current
limiter and a thermal shut-down mechanism.
The LP2985-XX is housed in a SOT23-5 5-lead package.
FEATURES
APPLICATIONS
• Very low consumption current: 85 mA typ. (when not loaded),
• Cellular phones, cordless phones, and 2-way radios
• Electronic notebooks, PDAs and palmtop computers
• Cameras, VCRs and camcorders
• PCMCIA cards
0.1 mA max. (when off)
• Very low dropout voltage: 100 mV typ. (I
• High precision output voltage: ±2%
• Output current capacity: 150 mA
= 50 mA)
OUT
• Modems
• Low noise: 30 mVRMS @ 20 Hz to 80 kHz (C = 10 nF)
n
• Battery-powered or hand-held instruments
• Good line regulation: 0.01%/V typ.
• Good load regulation: 30 mV typ. (I
= 1 to 150 mA)
OUT
• Low temperature drift co-efficient to V
: ±100 ppm/°C
OUT
• Built-in current limit and thermal shut-down
• Wide operating temperature range: –30 to +85 °C
• Preset output voltages: 1.8, 2.8, 3.0, 3.3, 3.6, or 5.0 V
SIMPLIFIED DEVICE DIAGRAM
LP2985-XX
V
1
3
IN
5
V
OUT
BIAS
CURRENT
LIMIT
ON/OFF
DRIVER
REFERENCE
NOISE
GND
4
2
THERMAL
SHUTDOWN
SL01545
Figure 1. Simplified device diagram.
2
2001 Oct 03
853–2291 27197
Philips Semiconductors
Product data
Micropower 150 mA low noise,
low dropout linear regulator
LP2985-XX
ORDERING INFORMATION
PACKAGE
TEMPERATURE
RANGE
TYPE NUMBER
NAME
DESCRIPTION
SOT23-5,
SOT25, SO5
LP2985-XXD
plastic small outline package; 5 leads (see dimensional drawing)
–30 to +85 °C
NOTE:
Part number marking
The device has five voltage output options, indicated by the XX on
the Type Number.
Each device is marked with a four letter code. The first three letters
designate the product. The fourth letter, represented by ‘x’, is a date
tracking code.
XX
18
28
30
33
36
50
VOLTAGE (Typical)
Part number
LP2985-18D
LP2985-28D
LP2985-30D
LP2985-33D
LP2985-36D
LP2985-50D
Marking
A A B x
A A C x
A B G x
A B H x
A N B x
A B J x
1.8 V
2.8 V
3.0 V
3.3 V
3.6 V
5.0 V
PIN CONFIGURATION
PIN DESCRIPTION
PIN SYMBOL
DESCRIPTION
1
2
3
4
V
Voltage input.
IN
1
2
3
5
V
OUT
V
IN
GND
Device ground.
ON/OFF
NOISE
ON/OFF control pin. Connect to V if not used.
IN
GND
Noise decrease pin, for connecting external
capacitor.
4
NOISE
ON/OFF
5
V
OUT
Voltage output.
SL01544
Figure 2. Pin configuration.
MAXIMUM RATINGS
SYMBOL
PARAMETER
MIN.
–0.3
–30
–40
–
MAX.
+12.0
+85
UNIT
V
V
Supply voltage
IN
T
Operating temperature
Storage temperature
Power dissipation
°C
oper
T
stg
+150
150
°C
P
D
mW
3
2001 Oct 03
Philips Semiconductors
Product data
Micropower 150 mA low noise,
low dropout linear regulator
LP2985-XX
ELECTRICAL CHARACTERISTICS
T
amb
= 25 °C, V = V
+ 1 V, V = 2.0 V, unless otherwise specified.
IN
OUT(nom)
ON/OFF
SYMBOL
PARAMETER
No-load input current
CONDITIONS
MIN.
–
TYP.
85
0
MAX.
130
0.1
UNIT
µA
I
I
= 0 mA
CC
OUT
I
Standby input current
Output voltage
V
–
µA
CC(OFF)
ON/OFF
98
–
102
1.836
2.856
3.060
3.366
3.672
5.100
0.2
% V
nom
V
OUT
LP2885-18
LP2885-28
LP2885-30
LP2885-33
LP2885-36
LP2885-50
1.764
2.744
2.940
3.234
3.528
4.900
–
1.8
2.8
3.0
3.3
3.6
5.0
0.1
10
30
100
70
60
30
5
V
V
V
V
V
V
V
–V
OUT
Dropout voltage
Line regulation
Load regulation
V
V
= V
= V
+ 1 to 10 V
+ 1 to 10 V
V
IN
IN
OUT(typ)
OUT(typ)
∆V
∆V
∆V
–
20
mV
mV
ppm/°C
dB
dB
LNR
IN
I
= 1 to 150 mA
–
90
LDR
OUT
OUT
/∆T
V
OUT
temperature coefficient
–30 °C ≤ T ≤ +85 °C
–
–
j
RR1
RR2
Ripple rejection 1
f = 120 Hz; V
= 1 V
50
–
ripple
Ripple rejection 2
f = 1 kHz; C = 0.01 µF; V
= 1 V
–
–
n
ripple
V
Output noise voltage
f
= 20 Hz to 80 kHz; C = 0.01 µF
–
–
µV
RMS
n
BW
n
I
ON/OFF pin input current
ON/OFF low threshold voltage
ON/OFF high threshold voltage
V
= 5.0 V
–
15
µA
ON/OFF
ON/OFF
V
–0.3
1.6
–
0.4
V
OFF
ON
V
–
V
+ 0.3
V
IN
4
2001 Oct 03
Philips Semiconductors
Product data
Micropower 150 mA low noise,
low dropout linear regulator
LP2985-XX
output voltage. If the feedback voltage is too high, the pass
transistor gate is pulled up, allowing less current to pass to the
output, resulting in a decrease in output voltage.
TECHNICAL DISCUSSION
As illustrated in Figure 3, the LP2985-XX consists of a band-gap
voltage reference, an error amplifier, P-channel pass transistor,
current limit circuit and an internal feedback voltage divider. The
output voltage is fed back through an internal resistor voltage divider
An external bypass capacitor connected to the NOISE pin reduces
noise at the output.
connected to the V
pin.
OUT
Additional functional blocks include a current-limiter, thermal sensor
and shut-down logic. The current-limiter monitors and controls the
pass-transistor’s gate voltage, limiting the output current to its
specified maximum value. Thus it can withstand a short-circuited
output for an indefinite amount of time without damaging the part.
The reference is connected to the error amplifier’s inverting input.
The error amplifier compares the reference with the feedback
voltage and amplifies the difference. If the feedback voltage is lower
than the reference voltage, the pass transistor’s gate is pulled lower,
which allows more current to pass to the output and increase the
LP2985-XX
V
1
3
IN
5
V
OUT
BIAS
CURRENT
LIMIT
ON/OFF
DRIVER
REFERENCE
NOISE
GND
4
2
THERMAL
SHUTDOWN
SL01545
Figure 3. Block diagram.
5
2001 Oct 03
Philips Semiconductors
Product data
Micropower 150 mA low noise,
low dropout linear regulator
LP2985-XX
good frequency characteristics is needed. Set it as close to the
APPLICATION INFORMATION
The following points have to be kept in mind for good performance
while using these devices:
circuit as possible and make the wiring as short as possible. The
value of the output capacitance must be at least 1 µF and must have
B-type temperature characteristics. Also it must have the ESR
(Equivalent Series Resistance) value within the stable range shown
Input Capacitor
in the ESR versus I plot.
An input capacitor of greater than 1 µF is required between the
LP2985-XX input pin and the circuit ground (the amount of
capacitance may be increased without limit). This capacitor must be
O
ON/OFF (Chip Enable) Pin
The ON/OFF pin must be actively terminated, not floating. If the
located as close as possible to the V or GND pin (not more than
IN
function is not to be used, the pin should be tied to V
.
IN
1 cm away from the pin) and returned to a clean analog ground.
Any good quality ceramic, tantalum, or film capacitor will work.
Line Impedance of VIN and GND
The V and GND lines should be sufficiently wide to minimize
Output Capacitor
Phase compensation is used for securing stable operation even if
the load current varies. For this reason, an output capacitor with
IN
impedance. If the impedance of these lines is high, there is a
chance to pick up noise or malfunction.
OUTPUT VOLTAGE
1 µF
0.01 µF
5
4
V
NOISE
OUT
V
ON/OFF
3
GND
2
IN
1
SUPPLY VOLTAGE
1 µF
SL01546
Figure 4. Typical application circuit, device always ON.
TEST CIRCUITS
A
V
1 µF
TEST LOAD
0.01 µF
5
4
V
NOISE
OUT
V
ON/OFF
3
GND
2
IN
1
A
A
SUPPLY VOLTAGE
1 µF
SL01547
Figure 5. Test circuit.
6
2001 Oct 03
Philips Semiconductors
Product data
Micropower 150 mA low noise,
low dropout linear regulator
LP2985-XX
PACKING METHOD
The LP2985-XX is packed in reels, as shown in Figure 6.
GUARD
BAND
TAPE
TAPE DETAIL
REEL
ASSEMBLY
COVER TAPE
CARRIER TAPE
BARCODE
LABEL
BOX
SL01305
Figure 6. Tape and reel packing method
7
2001 Oct 03
Philips Semiconductors
Product data
Micropower 150 mA low noise,
low dropout linear regulator
LP2985-XX
SOT23-5: plastic small outline package; 5 leads; body width 1.5 mm
1.2
1.0
0.55
0.41
0.22
0.08
3.00
2.70
1.70
1.50
0.55
0.35
0.025
1.35
8
2001 Oct 03
Philips Semiconductors
Product data
Micropower 150 mA low noise,
low dropout linear regulator
LP2985-XX
NOTES
9
2001 Oct 03
Philips Semiconductors
Product data
Micropower 150 mA low noise,
low dropout linear regulator
LP2985-XX
Data sheet status
Product
status
Definitions
[1]
Data sheet status
[2]
Objective data
Development
This data sheet contains data from the objective specification for product development.
Philips Semiconductors reserves the right to change the specification in any manner without notice.
Preliminary data
Product data
Qualification
Production
This data sheet contains data from the preliminary specification. Supplementary data will be
published at a later date. Philips Semiconductors reserves the right to change the specification
without notice, in order to improve the design and supply the best possible product.
This data sheet contains data from the product specification. Philips Semiconductors reserves the
right to make changes at any time in order to improve the design, manufacturing and supply.
Changes will be communicated according to the Customer Product/Process Change Notification
(CPCN) procedure SNW-SQ-650A.
[1] Please consult the most recently issued data sheet before initiating or completing a design.
[2] The product status of the device(s) described in this data sheet may have changed since this data sheet was published. The latest information is available on the Internet at URL
http://www.semiconductors.philips.com.
Definitions
Short-form specification — The data in a short-form specification is extracted from a full data sheet with the same type number and title. For
detailed information see the relevant data sheet or data handbook.
Limiting values definition — Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 60134). Stress above one
or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or
at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended
periods may affect device reliability.
Application information — Applications that are described herein for any of these products are for illustrative purposes only. Philips
Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or
modification.
Disclaimers
Life support — These products are not designed for use in life support appliances, devices or systems where malfunction of these products can
reasonably be expected to result in personal injury. Philips Semiconductors customers using or selling these products for use in such applications
do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application.
Righttomakechanges—PhilipsSemiconductorsreservestherighttomakechanges, withoutnotice, intheproducts, includingcircuits,standard
cells, and/or software, described or contained herein in order to improve design and/or performance. Philips Semiconductors assumes no
responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these
products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless
otherwise specified.
Koninklijke Philips Electronics N.V. 2001
Contact information
All rights reserved. Printed in U.S.A.
For additional information please visit
http://www.semiconductors.philips.com.
Fax: +31 40 27 24825
Date of release: 10-01
9397 750 08962
For sales offices addresses send e-mail to:
sales.addresses@www.semiconductors.philips.com.
Document order number:
Philips
Semiconductors
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