STMicroelectronics LD2981 Very low drop voltage regulators with inhibit Datasheet

LD2981
SERIES
ULTRA LOW DROP VOLTAGE REGULATORS WITH INHIBIT
LOW ESR OUTPUT CAPACITORS COMPATIBLE
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■
■
■
■
■
■
■
■
■
■
■
STABLE WITH LOW ESR CERAMIC
CAPACITORS
ULTRA LOW DROPOUT VOLTAGE (0.17V
TYP. AT 100mA LOAD, 7mV TYP. AT 1mA
LOAD)
VERY LOW QUIESCENT CURRENT (80µA
TYP. AT NO LOAD IN ON MODE; MAX 1µA
IN OFF MODE)
GUARANTEED OUTPUT CURRENT UP TO
100mA
LOGIC-CONTROLLED ELECTRONIC
SHUTDOWN
OUTPUT VOLTAGE OF 1.5; 1.8; 2.5; 2.85;
3.0; 3.2; 3.3; 3.6; 3.8; 4.0; 4.7; 4.85; 5.0V
INTERNAL CURRENT AND THERMAL LIMIT
± 0.75% TOLERANCE OUTPUT VOLTAGE
AVAILABLE (A VERSION)
OUTPUT LOW NOISE VOLTAGE 160µVRMS
TEMPERATURE RANGE: -40 TO 125°C
SMALLEST PACKAGE SOT23-5L AND
SOT-89
FAST DYNAMIC RESPONSE TO LINE AND
LOAD CHANGES
DESCRIPTION
The LD2981 series are 100mA fixed-output
voltage regulator. The low drop-voltage and the
SOT23-5L
SOT-89
ultra low quiescent current make them suitable for
low noise, low power applications and in battery
powered systems.
The quiescent current in sleep mode is less than
1µA when INHIBIT pin is pulled low. Shutdown
Logic Control function is available on pin n.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. The LD2981 is designed to
work with low ESR ceramic capacitor. Typical
applications are in cellular phone, palmtop/laptop
computer, personal digital assistant (PDA),
personal stereo, camcorder and camera.
SCHEMATIC DIAGRAM
September 2003
1/17
LD2981 SERIES
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
VI
VINH
Value
Unit
DC Input Voltage
-0.3 to 16
V
INHIBIT Input Voltage
-0.3 to 16
V
IO
Output Current
Internally limited
PD
Power Dissipation
Internally limited
TSTG
Storage Temperature Range
-55 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.
THERMAL DATA
Symbol
Parameter
Rthj-case Thermal Resistance Junction-case
Rthj-amb
Thermal Resistance Junction-ambient
SOT23-5L
SOT-89
Unit
81
15
°C/W
255
110
°C/W
CONNECTION DIAGRAM (top view)
SOT23-5L
SOT-89
PIN DESCRIPTION
Pin N°
SOT23-5L
Pin N°
SOT-89
Symbol
1
3
VIN
2
3
2
GND
INHIBIT
4
5
2/17
1
NC
VOUT
Name and Function
Input Port
Ground Pin
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
Not Connected
Output Port
LD2981 SERIES
ORDERING CODES
AB VERSION
SOT23-5L
LD2981ABM25TR
LD2981ABM28TR
LD2981ABM30TR
LD2981ABM32TR
LD2981ABM33TR
LD2981ABM36TR
LD2981ABM38TR
LD2981ABM40TR
LD2981ABM47TR
LD2981ABM48TR
LD2981ABM50TR
C VERSION
SOT-89
SOT23-5L
SOT-89
OUTPUT
VOLTAGES
LD2981ABU25TR
LD2981ABU28TR
LD2981ABU30TR
LD2981ABU32TR
LD2981ABU33TR
LD2981ABU36TR
LD2981ABU38TR
LD2981ABU40TR
LD2981ABU47TR
LD2981ABU48TR
LD2981ABU50TR
LD2981CM15TR
LD2981CM18TR
LD2981CM25TR
LD2981CM28TR
LD2981CM30TR
LD2981CM32TR
LD2981CM33TR
LD2981CM36TR
LD2981CM38TR
LD2981CM40TR
LD2981CM47TR
LD2981CM48TR
LD2981CM50TR
LD2981CU15TR
LD2981CU18TR
LD2981CU25TR
LD2981CU28TR
LD2981CU30TR
LD2981CU32TR
LD2981CU33TR
LD2981CU36TR
LD2981CU38TR
LD2981CU40TR
LD2981CU47TR
LD2981CU48TR
LD2981CU50TR
1.5 V
1.8 V
2.5 V
2.85 V
3.0 V
3.2 V
3.3 V
3.6 V
3.8 V
4.0 V
4.7 V
4.85 V
5.0 V
TYPICAL APPLICATION CIRCUIT
(*) Inhibit Pin is not internally pulled-up then it must not be left floating. Disable the device when connected to GND or to a positive voltage
less than 0.18V.
3/17
LD2981 SERIES
ELECTRICAL CHARACTERISTICS FOR LD2981AB (Tj = 25°C, VI = VO(NOM) +1V, C I = 1µF(X7R),
CO = 2.2µF(X7R), IO = 1mA, VINH = 2V, unless otherwise specified)
Symbol
Parameter
VOP
Operating Input Voltage
VO
Output Voltage
Test Conditions
IO = 1 to 100 mA
Output Voltage
2.481
TJ= -40 to 125°C
IO = 1 mA
IO = 1 to 100 mA
Output Voltage
TJ= -40 to 125°C
IO = 1 mA
IO = 1 to 100 mA
Output Voltage
Output Voltage
Output Voltage
TJ= -40 to 125°C
Output Voltage
Output Voltage
Output Voltage
TJ= -40 to 125°C
3.267
TJ= -40 to 125°C
IO = 1 mA
TJ= -40 to 125°C
4/17
3.3
3.224
3.325
3.627
3.564
3.636
3.690
3.8
3.829
3.762
3.838
3.705
3.895
IO = 1 mA
3.97
3.96
4.04
3.9
4.1
IO = 1 mA
4.664
IO = 1 to 100 mA
4.653
TJ= -40 to 125°C
4.813
IO = 1 to 100 mA
4.801
TJ= -40 to 125°C
IO = 1 mA
TJ= -40 to 125°C
4.7
V
V
V
4.03
4.735
V
V
V
V
4.747
4.817
4.85
4.887
V
4.899
4.729
4.962
VO(NOM) + 1 < VIN < 16 V IO = 1 mA
TJ= -40 to 125°C
4
4.582
IO = 1 mA
V
3.383
3.6
IO = 1 to 100 mA
TJ= -40 to 125°C
Unit
3.333
3.510
3.771
TJ= -40 to 125°C
3.2
3.217
3.573
IO = 1 mA
IO = 1 to 100 mA
Line Regulation
3.030
3.075
3.275
IO = 1 to 100 mA
∆VO
3.023
2.970
IO = 1 mA
IO = 1 to 100 mA
VO
3
2.925
IO = 1 to 100 mA
IO = 1 to 100 mA
VO
2.878
2.921
3.28
IO = 1 to 100 mA
VO
2.822
2.779
3.12
IO = 1 to 100 mA
Output Voltage
2.872
3.232
IO = 1 to 100 mA
VO
2.85
3.168
IO = 1 to 100 mA
Output Voltage
2.525
2.562
3.176
IO = 1 to 100 mA
VO
V
IO = 1 mA
IO = 1 to 100 mA
VO
V
2.518
IO = 1 to 100 mA
IO = 1 to 100 mA
VO
16
2.5
2.475
2.977
IO = 1 to 100 mA
VO
Max.
2.437
2.828
IO = 1 to 100 mA
VO
Typ.
2.5
IO = 1 mA
IO = 1 to 100 mA
VO
Min.
4.971
5
5.038
4.950
5.050
4.875
5.125
0.003
0.014
0.032
V
%/V
LD2981 SERIES
Symbol
IQ
Parameter
Quiescent Current
ON MODE
Test Conditions
Min.
IO = 0
80
100
IO = 25 mA
Dropout Voltage (NOTE 1)
0.8
2
TJ= -40 to 125°C
IO = 0
1
TJ= -40 to 125°C
70
100
150
180
Short Circuit Current
RL = 0
SVR
Supply Voltage Rejection
CO = 10µF
VINH
Inhibit Input Logic Low
LOW = Output OFF
TJ= -40 to 125°C
VINL
Inhibit Input Logic High
HIGH = Output ON
TJ= -40 to 125°C
IINH
Inhibit Input Current
250
375
TJ= -40 to 125°C
IO = 100mA
f = 1KHz
150
mA
63
dB
0.18
1.6
VINH = 0V
TJ= -40 to 125°C
0
-1
TJ= -40 to 125°C
5
15
CO = 10 µF
V
V
VINH = 5V
BW = 300 Hz to 50 KHz
mV
15
IO = 100mA
Thermal Shutdown
10
TJ= -40 to 125°C
IO = 25mA
Output Noise Voltage
7
TJ= -40 to 125°C
IO = 1mA
3
5
IO = 25mA
eN
1300
VINH < 0.3 V
IO = 0
TSHDN
1000
2600
IO = 1mA
ISC
150
400
TJ= -40 to 125°C
VINH < 0.15 V
VDROP
µA
800
IO = 100 mA
IO = 100 mA
100
250
TJ= -40 to 125°C
IO = 25 mA
Unit
200
TJ= -40 to 125°C
IO = 1 mA
Max.
150
TJ= -40 to 125°C
IO = 0
IO = 1 mA
OFF MODE
Typ.
µA
160
µVRMS
170
°C
(NOTE 1): For Vo < 2.5V dropout voltage can be calculated according to the minimum input voltage in full temperature range.
5/17
LD2981 SERIES
ELECTRICAL CHARACTERISTICS FOR LD2981C (Tj = 25°C, VI = VO(NOM) +1V, C I = 1µF(X7R),
CO = 2.2µF(X7R), IO = 1mA, VINH = 2V, unless otherwise specified)
Symbol
Parameter
VOP
Operating Input Voltage
VO
Output Voltage
Test Conditions
IO = 1 to 100 mA
Output Voltage
1.478
TJ= -40 to 125°C
IO = 1 mA
IO = 1 to 100 mA
Output Voltage
TJ= -40 to 125°C
IO = 1 mA
IO = 1 to 100 mA
Output Voltage
Output Voltage
Output Voltage
TJ= -40 to 125°C
Output Voltage
Output Voltage
Output Voltage
TJ= -40 to 125°C
2.94
TJ= -40 to 125°C
IO = 1 mA
TJ= -40 to 125°C
3.264
3.312
3.3
3.341
3.234
3.366
3.184
3.415
3.528
3.672
3.474
3.726
IO = 1 mA
3.752
3.724
TJ= -40 to 125°C
3.95
IO = 1 to 100 mA
3.92
TJ= -40 to 125°C
IO = 1 mA
TJ= -40 to 125°C
IO = 1 mA
IO = 1 to 100 mA
V
V
V
3.847
V
V
V
V
3.876
3.933
4
4.05
V
4.08
4.14
4.7
4.758
4.606
4.794
4.864
4.85
4.91
4.753
4.947
4.68
5.019
4.937
TJ= -40 to 125°C
3.645
4.535
4.789
TJ= -40 to 125°C
3.8
3.86
4.641
IO = 1 mA
3.6
3.667
IO = 1 mA
IO = 1 to 100 mA
6/17
3.24
3.136
IO = 1 to 100 mA
V
3.105
3.2
3.555
TJ= -40 to 125°C
Unit
3.06
IO = 1 mA
IO = 1 to 100 mA
Output Voltage
3.037
IO = 1 to 100 mA
IO = 1 to 100 mA
VO
3
2.885
3.088
3.258
TJ= -40 to 125°C
2.85
2.895
3.16
IO = 1 mA
IO = 1 to 100 mA
Output Voltage
2.55
2.587
2.962
IO = 1 to 100 mA
VO
2.531
2.45
IO = 1 mA
IO = 1 to 100 mA
VO
2.5
2.412
IO = 1 to 100 mA
IO = 1 to 100 mA
VO
1.836
1.863
2.949
IO = 1 to 100 mA
VO
1.764
1.737
2.75
IO = 1 to 100 mA
Output Voltage
1.822
2.907
IO = 1 to 100 mA
VO
1.8
2.793
IO = 1 to 100 mA
Output Voltage
1.530
1.555
2.814
IO = 1 to 100 mA
VO
V
IO = 1 mA
IO = 1 to 100 mA
VO
V
1.522
IO = 1 to 100 mA
IO = 1 to 100 mA
VO
16
1.5
1.470
2.468
IO = 1 to 100 mA
VO
Max.
1.445
1.777
IO = 1 to 100 mA
VO
Typ.
2.5
IO = 1 mA
IO = 1 to 100 mA
VO
Min.
5
5.062
4.9
5.1
4.825
5.175
V
V
V
LD2981 SERIES
Symbol
∆VO
Parameter
Line Regulation
Test Conditions
Min.
VO(NOM) + 1 < VIN < 16 V IO = 1 mA
Typ.
0.003
Quiescent Current
ON MODE
IO = 0
80
IO = 1 mA
100
IO = 25 mA
250
IO = 100 mA
1000
OFF MODE
VINH < 0.3 V
Dropout Voltage (NOTE 1)
400
1300
2
TJ= -40 to 125°C
IO = 0
1
3
7
10
15
TJ= -40 to 125°C
IO = 1mA
IO = 25mA
70
IO = 100mA
180
250
375
TJ= -40 to 125°C
IO = 100mA
100
150
TJ= -40 to 125°C
IO = 25mA
Short Circuit Current
RL = 0
SVR
Supply Voltage Rejection
CO = 10µF
VINH
Inhibit Input Logic Low
LOW = Output OFF
TJ= -40 to 125°C
VINL
Inhibit Input Logic High
HIGH = Output ON
TJ= -40 to 125°C
IINH
Inhibit Input Current
VINH = 0V
TJ= -40 to 125°C
0
-1
VINH = 5V
TJ= -40 to 125°C
5
15
eN
TSHDN
Output Noise Voltage
Thermal Shutdown
150
f = 1KHz
BW = 300 Hz to 50 KHz
CO = 10 µF
mV
5
TJ= -40 to 125°C
IO = 0
IO = 1mA
ISC
150
0.8
VINH < 0.15 V
VDROP
µA
2600
TJ= -40 to 125°C
IO = 100 mA
100
800
TJ= -40 to 125°C
IO = 25 mA
%/V
200
TJ= -40 to 125°C
IO = 1 mA
0.014
150
TJ= -40 to 125°C
IO = 0
Unit
0.032
TJ= -40 to 125°C
IQ
Max.
mA
63
dB
0.18
1.6
V
V
µA
160
µVRMS
170
°C
(NOTE 1): For Vo < 2.5V dropout voltage can be calculated according to the minimum input voltage in full temperature range.
7/17
LD2981 SERIES
TYPICAL PERFORMANCE CHARACTERISTICS (Tj = 25°C, VI = VO(NOM) +1V, CI = 1µF(X7R),
CO = 2.2µF(X7R), VINH = 2V, unless otherwise specified)
Figure 1 : Output Voltage vs Temperature
Figure 4 : Load Regulation vs Temperature
Figure 2 : Output Voltage vs Temperature
Figure 5 : Dropout Voltage vs Temperature
Figure 3 : Line Regulation vs Temperature
Figure 6 : Quiescent Current vs Temperature
8/17
LD2981 SERIES
Figure 7 : Quiescent Current vs Output
Current
Figure 10 : Dropout Voltage vs Output Current
Figure 8 : OFF MODE Quiescent Current vs
Temperature
Figure 11 : Inhibit Input Current vs Temperature
Figure 9 : Quiescent Current vs Input Voltage
Figure 12 : Inhibit Voltage vs Temperature
9/17
LD2981 SERIES
Figure 13 : Supply Voltage Rejection vs
Frequency
Figure 16 : Worst Case: Lowest Output Version
Figure 14 : Noise Voltage vs Frequency
Figure 17 : Load Transient Response
VO = 4.7V, IO = 1 to 100mA, CO = 4.7µF X7R
Figure 15 : Best Case: Highest Output Version
Figure 18 : Line Transient Response
VI = (VO(NOM) + 1V), VO = 4.7V, IO = 100mA, CO = 4.7µF X7R
10/17
LD2981 SERIES
APPLICATION NOTES
EXTERNAL CAPACITORS
Like any low-dropout regulator, the LD2981 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.
INPUT CAPACITOR
An input capacitor whose value is 1µF is required with the LD2981 (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.
OUTPUT CAPACITOR
The LD2981 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. The figures 1 and 2 show the allowable ESR range as a function of the output
capacitance. These curves represent the stability region over the full temperature and IO range. 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 1µF for output voltages equal or major than
3.8V, 2.2µF for output voltages from 2.85 to 3.3V, and 3.3µF 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 (see Figure1 & Figure2 to choose the right value according to the used version
and keeping in account that the ESR of ceramic capacitors has been measured @ 100KHz).
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.
INHIBIT INPUT OPERATION
The inhibit pin can be used to turn OFF the regulator when pulled low, so drastically reducing the current
consumption down to less than 1µA. 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.
REVERSE CURRENT
The power transistor used in the LD2981 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,
according to the test circuit in figure 19, flows to the GND across the two feedback resistors. This current
typical value is 160µA. R1 and R 2 resistors are implanted type; typical values are, respectively, 42.6 KΩ
and 51.150 KΩ.
11/17
LD2981 SERIES
Figure 19 : Reverse Current Test Circuit
12/17
LD2981 SERIES
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
68.8
e
0.95
37.4
H
2.60
3.00
102.3
118.1
L
0.10
0.60
3.9
23.6
.
7049676C
13/17
LD2981 SERIES
SOT-89 MECHANICAL DATA
mm.
mils
DIM.
MIN.
TYP
MAX.
MIN.
TYP.
MAX.
A
1.4
1.6
55.1
63.0
B
0.44
0.56
17.3
22.0
B1
0.36
0.48
14.2
18.9
C
0.35
0.44
13.8
17.3
C1
0.35
0.44
13.8
17.3
D
4.4
4.6
173.2
181.1
D1
1.62
1.83
63.8
72.0
E
2.29
2.6
90.2
102.4
e
1.42
1.57
55.9
61.8
e1
2.92
3.07
115.0
120.9
H
3.94
4.25
155.1
167.3
L
0.89
1.2
35.0
47.2
P025H
14/17
LD2981 SERIES
Tape & Reel SOT23-xL MECHANICAL DATA
mm.
inch
DIM.
MIN.
TYP
A
MAX.
MIN.
TYP.
180
13.0
7.086
C
12.8
D
20.2
0.795
N
60
2.362
T
13.2
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
15/17
LD2981 SERIES
Tape & Reel SOT89 MECHANICAL DATA
mm.
inch
DIM.
MIN.
TYP
A
MIN.
TYP.
180
13.0
13.2
MAX.
7.086
C
12.8
D
20.2
0.795
N
60
2.362
T
16/17
MAX.
0.504
0.512
14.4
0.519
0.567
Ao
4.70
4.80
4.90
0.185
0.189
0.193
Bo
4.30
4.40
4.50
0.169
0.173
0.177
Ko
1.70
1.80
1.90
0.067
0.071
0.075
Po
3.9
4.0
4.1
0.153
0.157
0.161
P
7.9
8.0
8.1
0.311
0.315
0.319
LD2981 SERIES
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