STMICROELECTRONICS LD2982BM18R

LD2982BXX18
Very low drop and low noise voltage regulator with
inhibit function, low ESR capacitors compatible
Features
■
Very low dropout voltage (120 mV at 50 mA
and 7 mV at 1 mA load)
■
Very low quiescent current (375 mA typ. at
50 mA load and 75 mA at 1 mA)
■
Output current up to 50 mA
■
Logic controlled electronic shutdown
■
Output voltage of 1.8 V
■
Internal current and thermal limit
■
Available in ± 1 % tolerance
(at 25 °C, A version)
■
Supply voltage rejection: 45 dB (typ)
■
Only 1 µF for stability
■
Low output noise voltage 30 µVrms
■
Smallest package SOT23-5L
■
Temperature range: -40 °C to 125 °C
SOT23-5L
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Typical application are in cellular phone,
palmtop/laptop computer, personal digital
assistant (PDA), personal stereo, camcorder and
camera.
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Description
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The LD2982 is a 50 mA fixed output voltage
regulator. The ultra low drop voltage and the low
quiescent current make them particularly suitable
for low noise, low power applications, and in
battery powered systems. In sleep mode
quiescent current is less than 1 µA when INHIBIT
pin is pulled low. Shutdown logic control function
is available on pin 3 (TTL compatible). This
means that when the device is used as local
regulator, it is possible to put a part of the board in
standby, decreasing the total power consumption.
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An external capacitor CBYP = 10 nF connected
between bypass pin and GND reduce the noise to
30 µVrms.
Table 1.
July 2009
Device summary
Order code
Output voltage
LD2982BM18R
1.8 V
Doc ID 8188 Rev 7
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www.st.com
17
Contents
LD2982BXX18
Contents
1
Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5
Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6
Application notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
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6.1
External capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.2
Input capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.3
Output capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.4
Important . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.5
Inhibit input operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
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Package mechanical data . . . . . . .b
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
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Revision history . . . . . . )
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
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6.6
7
8
Reverse current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
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Doc ID 8188 Rev 7
LD2982BXX18
Diagram
1
Diagram
Figure 1.
Schematic diagram
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Pin configuration
LD2982BXX18
2
Pin configuration
Figure 2.
Pin connections (top view)
Table 2.
Pin description
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Pin n°
Symbol
1
IN
2
GND
3
INHIBIT
Control switch ON/OFF. Inhibit is not internally pulled-up; it cannot be left floating.
Disable the device when connected to GND or to a positive voltage less than 0.18V
4
Bypass
Bypass Pin: Capacitor to be connected to GND in order to improve the thermal noise
performances
5
OUT
Table 3.
Name and function
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Input port
Ground pin
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Output port
Thermal data
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Symbol
Parameter
SOT23-5L
Unit
RthJC
Thermal resistance junction-case
81
°C/W
RthJA
Thermal resistance junction-ambient
255
°C/W
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LD2982BXX18
Maximum ratings
3
Maximum ratings
Table 4.
Absolute maximum ratings
Symbol
VI
Parameter
VINH
Note:
Value
Unit
DC input voltage
16
V
INHIBIT input voltage
16
V
IO
Output current
Internally limited
PD
Power dissipation
Internally limited
TSTG
Storage temperature range
-65 to 150
°C
TOP
Operating junction temperature range
-40 to 125
°C
Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.
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Electrical characteristics
4
LD2982BXX18
Electrical characteristics
TJ = 25 °C, VI = VO + 1 V, IO = 1 mA, VSHDN = 2 V, CI = CO = 1 µF, unless otherwise
specified.
Table 5.
Electrical characteristics for LD2982BXX18
Symbol
VOP
Parameter
Test conditions
Min.
Operating input voltage
2.5
VI = 2.5V
VO
VO
VO
VO
Output voltage
Output voltage
Output voltage
Output voltage
1.477
1.530
VI = 2.8V
1.773
IO = 1 to 50mA
1.764
IO = 1 to 50mA, TJ= -40 to 125°C
1.737
VI = 3.5V
2.462
IO = 1 to 50mA
2.45
IO = 1 to 50mA, TJ= -40 to 125°C
2.412
VI = 3.8V
2.758
IO = 1 to 50mA
2.744
VO
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VO
VO
VO
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Output voltage
Output voltage
Output voltage
2.807
1.836
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2.537
2.55
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2.8
2.842
2.856
2.85
3.0
2.94
2.895
2.893
V
3.045
3.06
V
3.105
3.1
3.146
IO = 1 to 50mA
3.038
3.162
IO = 1 to 50mA, TJ= -40 to 125°C
2.991
3.208
VI = 4.2V
3.152
IO = 1 to 50mA
3.136
3.264
IO = 1 to 50mA, TJ= -40 to 125°C
3.088
3.312
VI = 4.3V
3.250
3.2
3.3
V
3.349
IO = 1 to 50mA
3.234
3.366
3.184
3.415
VI = 4.5V
3.447
IO = 1 to 50mA
3.430
3.5
V
3.248
IO = 1 to 50mA, TJ= -40 to 125°C
V
3.552
3.370
IO = 1 to 50mA, TJ= -40 to 125°C
3.377
VI = 4.6V
3.546
IO = 1 to 50mA
3.528
3.672
IO = 1 to 50mA, TJ= -40 to 125°C
3.474
3.726
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V
2.898
2.907
3.053
V
2.587
2.950
IO = 1 to 50mA, TJ= -40 to 125°C
V
1.863
2.5
2.793
2.955
V
1.827
2.750
VI = 4.1V
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Output voltage
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IO = 1 to 50mA
Output voltage
1.523
1.553
VI = 4.0V
VO
V
1.470
IO = 1 to 50mA
Output voltage
16
1.447
IO = 1 to 50mA, TJ= -40 to 125°C
VO
Unit
IO = 1 to 50mA
VI = 3.85V
Output voltage
1.5
Max.
IO = 1 to 50mA, TJ= -40 to 125°C
IO = 1 to 50mA, TJ= -40 to 125°C
VO
Typ.
V
3.662
3.6
3.654
V
LD2982BXX18
Table 5.
Electrical characteristics
Electrical characteristics for LD2982BXX18 (continued)
Symbol
VO
Parameter
Test conditions
Output voltage
VO
Output voltage
VO
Output voltage
VO
Output voltage
Min.
Typ.
Max.
VI = 4.8V
3.743
3.8
3.857
IO = 1 to 50mA
3.724
IO = 1 to 50mA, TJ= -40 to 125°C
3.667
VI = 5.0V
3.94
IO = 1 to 50mA
3.92
4.08
IO = 1 to 50mA, TJ= -40 to 125°C
3.86
4.14
VI = 5.7V
4.629
IO = 1 to 50mA
4.606
4.794
IO = 1 to 50mA, TJ= -40 to 125°C
4.535
4.864
VI = 6.0V
4.925
IO = 1 to 50mA
IO = 1 to 100 mA, TJ= -40 to 125°C
Short circuit current
ISC
3.876
4.7
5
5.1
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IO = 1mA
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IO = 10mA
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120
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OFF MODE
80
IO = 1mA
100
200
IO = 10mA, TJ= -40 to 125°C
600
IO = 50mA, TJ= -40 to 125°C
VIH
Inhibit input logic high
TJ= -40 to 125°C
IINH
Inhibit input current
eN
Output noise voltage
300
900
1
45
dB
0.15
2
V
V
VINH = 0V, TJ= -40 to 125°C
5
15
VINH = 5V, TJ= -40 to 125°C
0
-1
B = 300 Hz to 50 kHz, CBYP = 0.01µF,
CO = 10µF
30
Doc ID 8188 Rev 7
µA
0
VINH<0.18V, TJ= -40 to 125°C
TJ= -40 to 125°C
150
1200
VINH<0.18V
CBYP = 0.01µF, CO = 10µF, f = 1kHz
100
400
IO = 50mA
Supply voltage rejection
150
200
IO = 10mA
Inhibit input logic low
mV
150
IO = 1mA, TJ= -40 to 125°C
VIL
SVR
60
225
IO = 0, TJ= -40 to 125°C
IQ
10
90
IO = 0
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3
15
IO = 50mA, TJ= -40 to 125°C
Quiescent current
ON MODE
%/VI
5
IO = 10mA, TJ= -40 to 125°C
IO = 50mA
0.014
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IO = 1mA, TJ= -40 to 125°C
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mA
0.032
IO = 0, TJ= -40 to 125°C
Dropout voltage
V
400
VI = VO + 1V to 16V, IO = 1 mA,
TJ= -40 to 125°C
V
5.075
5.175
0.003
V
4.77
4.9
IO = 0
VDROP
4.06
4.825
RL = 0
Line regulation
V
3.933
4
VI = VO + 1V to 16V, IO = 1 mA
ΔVO/ΔVI
Unit
µA
µV
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Typical characteristics
LD2982BXX18
5
Typical characteristics
Figure 3.
(TJ = 25 °C, VI = VO(NOM) +1 V, CI = 1 µF (X7R), CO = 2.2 µF (X7R), VINH = 2 V, unless
otherwise specified).
Output voltage vs. temperature
Figure 4.
Dropout voltage vs. temperature
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Figure 5.
Dropout voltage vs. output current Figure 6.
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Quiescent current vs. load current
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Figure 7.
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Quiescent current vs. temperature
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Figure 8.
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Supply voltage rejection vs. temp.
LD2982BXX18
Figure 9.
Typical characteristics
Supply voltage rejection vs. output Figure 10. Supply voltage rejection vs. output
current
current
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Figure 11. Supply voltage rejection vs.
frequency
Figure 12. Supply voltage rejection vs.
frequency
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Figure 13. Line transient
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Figure 14. Line transient
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VO = 2.5V, IO = 50mA, no CI, CO = 4.7µF, tr=tf=2ns
VO = 2.5V, IO = 50mA, no CI, CO = 4.7µF, tr=tf=1µs
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Typical characteristics
LD2982BXX18
Figure 15. Load transient
Figure 16. Load transient
VO = 2.5V, IO = 0 to 50mA, no CI, CO = 10µF, tr=tf=2ns
VO = 2.5V, IO = 0 to 50mA, no CI, CO = 4.7µF, tr=tf=2ns
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LD2982BXX18
Application notes
6
Application notes
6.1
External capacitors
Like any low-dropout regulator, the LD2982 requires external capacitors for regulator
stability. This capacitor must be selected to meet the requirements of minimum capacitance
and equivalent series resistance. We suggest to solder input and output capacitors as close
as possible to the relative pins.
6.2
Input capacitor
An input capacitor whose value is 1 µF is required with the LD2982 (amount of capacitance
can be increased without limit). This capacitor must be located a distance of not more than
0.5" from the input pin of the device and returned to a clean analog ground. Any good quality
ceramic, tantalum or film capacitors can be used for this capacitor.
6.3
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Output capacitor
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The LD2982 is designed specifically to work with ceramic output capacitors. It may also be
possible to use tantalum capacitors, but these are not as attractive for reasons of size and
cost. By the way, the output capacitor must meet both the requirement for minimum amount
of capacitance and ESR (equivalent series resistance) value. Due to the different loop gain,
the stability improves for higher output versions and so the suggested minimum output
capacitor value, if low ESR ceramic type is used, is 1 µF for output voltages equal or major
than 3.8 V, 2.2 µF for VO going from 1.8 to 3.3 V, and 3.3 µF for the other versions. However,
if an output capacitor lower than the suggested one is used, it's possible to make stable the
regulator adding a resistor in series to the capacitor.
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6.4
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Important
The output capacitor must maintain its ESR in the stable region over the full operating
temperature to assure stability. Also, capacitor tolerance and variation with temperature
must be considered to assure the minimum amount of capacitance is provided at all times.
This capacitor should be located not more than 0.5" from the output pin of the device and
returned to a clean analog ground.
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6.5
The inhibit pin can be used to turn OFF the regulator when pulled low, so drastically
reducing the current consumption down to less than 1 µA. When the inhibit feature is not
used, this pin must be tied to VI to keep the regulator output ON at all times. To assure
proper operation, the signal source used to drive the inhibit pin must be able to swing above
and below the specified thresholds listed in the electrical characteristics section under VIH
VIL. Any slew rate can be used to drive the inhibit.
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Application notes
6.6
LD2982BXX18
Reverse current
The power transistor used in the LD2982 has not an inherent diode connected between the
regulator input and output. If the output is forced above the input, no current will flow from
the output to the input across the series pass transistor. When a VREV voltage is applied on
the output, the reverse current measured flows to the GND across the two feedback
resistors. This current typical value is 160 µA. R1 and R2 resistors are implanted type;
typical values are, respectively, 42.6 kΩ and 51.150 kΩ.
Figure 17. Reverse current test circuit
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LD2982BXX18
7
Package mechanical data
Package mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
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Package mechanical data
LD2982BXX18
SOT23-5L mechanical data
mm.
mils.
Dim.
Min.
Typ.
Max.
Min.
Typ.
Max.
A
0.90
1.45
35.4
57.1
A1
0.00
0.10
0.0
3.9
A2
0.90
1.30
35.4
51.2
b
0.35
0.50
13.7
19.7
C
0.09
0.20
3.5
7.8
D
2.80
3.00
110.2
118.1
E
1.50
1.75
59.0
e
0.95
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68.8
37.4
H
2.60
3.00
L
0.10
0.60
102.3
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3.9
118.1
23.6
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LD2982BXX18
Package mechanical data
Tape & reel SOT23-xL mechanical data
mm.
inch.
Dim.
Min.
Typ.
Max.
A
Min.
Typ.
180
13.0
7.086
C
12.8
13.2
D
20.2
0.795
N
60
2.362
T
Max.
0.504
0.512
14.4
0.519
0.567
Ao
3.13
3.23
3.33
0.123
0.127
0.131
Bo
3.07
3.17
3.27
0.120
0.124
0.128
Ko
1.27
1.37
1.47
0.050
0.054
0.0.58
Po
3.9
4.0
4.1
0.153
0.157
0.161
P
3.9
4.0
4.1
0.153
0.157
0.161
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Revision history
LD2982BXX18
8
Revision history
Table 6.
Document revision history
Date
Revision
Changes
25-Jul-2006
4
Order codes updated.
14-Feb-2008
5
Added: Table 1 on page 1.
10-Jul-2008
6
Modified: Table 1 on page 1 and Table 5 on page 6.
29-Jul-2009
7
Modified: Table 1 on page 1.
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LD2982BXX18
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Doc ID 8188 Rev 7
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