This is information on a product in full production.
February 2014 DocID11039 Rev 9 1/21
21
LDS3985
Very low drop and low noise BiCMOS 300 mA
voltage regulator
Datasheet
-
production data
Features
•Input voltage from 2.5 V to 6 V
•Stable with low ESR ceramic capacitors
•Very low dropout voltage (150 mV typ. at 300
mA load, 0.4 mV typ. at 1 mA load)
•Very low quiescent curr ent (85 µA typ. at no
load, 200 µA typ. at 300 mA load; max.1.5 µA
in OFF mode)
•Guaranteed output current up to 300 mA
•Wide range of output voltages available on
request: fixed from 1.25 V to 5 V with 100 mV
step
•Fast turn-on time: typ. 240 µs
–[C
O
= 2.2 µF, C
BYP
= 33 nF and I
O
= 1 mA]
•Logic-controlled electronic shutdown
•Internal current and thermal limit
•Low output voltage noise: 30 µ V
RMS
over 10
Hz to 100 kHz
•SVR of 55 dB at 1 kHz, 50 dB at 10 kHz
•Temperature range: - 40 °C to 125 °C
•Automotive grade product available in DFN6
package, temperature range: - 40 °C to 85 °C
Description
The LDS3985 provides up to 300 mA, from 2.5 V
to 6 V input voltage. It is stable with ceramic and
high quality tantalum capacitor . The ultra low drop
voltage, low quies ce nt cur rent and low noise
make it suitable for low power applications and
battery-powered systems. Shutdown logic control
function is available, 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. Typical applications are
mobile phone s and si mi lar battery-powe re d
wireless systems, portable information
appliances.
SOT23-5L
Table 1. Device summary
Packages
Output voltage
SOT23-5L DFN6 DFN6
(automotive grade)
LDS3985M15R LDS3985PU15R LDS3985PU15RY 1.5 V
LDS3985M18R LDS3985PU18RY 1.8 V
LDS3985M25R LDS3985PU25RY 2.5 V
LDS3985M28R LDS3985PU28R LDS3985PU28RY 2.8 V
LDS3985M30R LDS3985PU30RY 3.0 V
LDS3985M33R LDS3985PU33R LDS3985PU33RY 3.3 V
LDS3985M50R 5.0 V
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Contents LDS3985
2/21 DocID11039 Rev 9
Contents
1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7 Packaging mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
DocID11039 Rev 9 3/21
LDS3985 Diagram
1 Diagram
Figure 1. Schematic diag ram
Pin configuration LDS3985
4/21 DocID11039 Rev 9
2 Pin configuration
Figure 2. Pin connections (top view for SOT23-5L, and for DFN6)
')1
627/
Table 2. Pin description
Pin n° for
SOT23-5L Pin n° for
DFN6 Symbol Name and functi on
11V
I
LDO input voltage.
2 5 GND Common ground.
36V
INH
Inhibit input vo lta ge: O N mode wh en V
INH
≥ 1 .2 V, OFF mode wh en V
INH
≤
0.4 V (do not leave it floating; it is not internally pulled down/up).
4 4 Bypass Bypass pin: an external capacitor to be connected (usually 10 nF) to
minimize noise voltage
53V
O
LDO output voltage
- 2 N.C. Not connected.
DocID11039 Rev 9 5/21
LDS3985 Maximum ratings
3 Maximum ratings
Note: Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.
Table 3. Absolute maximum ratings
Symbol Parameter Value Unit
V
I
DC input voltage -0.3 to 6
(1)
1. The input pin is able to withstand non repetitive spike of 6.5 V for 200 ms.
V
V
O
DC output volt ag e -0.3 to V
I
+ 0.3 V
V
INH
Inhibit input voltage -0.3 to V
I
+ 0.3 V
I
O
Output current Internally limited
P
D
Power dissipation Internally limited
T
STG
Storage temperature range -65 to 150 °C
T
OP
Operating junction temperature range -40 to 125 °C
Operating junction temperature range, automotive
grade version - 40 to 85 °C
Table 4. Thermal data
Symbol Parameter SOT23-5L DFN6 Unit
R
thJC
Thermal resistance junction-case 81 10 °C/W
R
thJA
Thermal resistance junction-ambient 255 55 °C/W
Ele ctrical characteristics LDS398 5
6/21 DocID11039 Rev 9
4 Electrical characteristics
T
J
= 25 °C, V
I
= V
O(NOM)
+ 0.5 V, C
I
= 1 µF, C
O
= 2.2 µF, C
BYP
= 33 nF, I
O
= 1 mA,
V
INH
= 1.4 V, unless otherwis e specif ied .
Table 5. LDS3985 electrical characteristics
Symbol Parameter Test conditions Min. Typ. Max. Unit
V
I
Operating input voltage 2.5 6 V
V
O
Output voltage < 2.5 V I
O
= 1 mA -50 50 mV
T
J
= - 40 to 125 °C -75 75
V
O
Output voltage ≥ 2.5 V I
O
= 1 mA -2 2 %
V
O(NOM)
T
J
= - 40 to 125 °C -3 3
ΔV
O
Line regulation
(1)
V
I
= V
O(NOM)
+ 0.5 to 6 V,
T
J
= - 40 to 125 °C -0.1 0.1 %/V
V
O
= 4.7 to 5 V -0.19 0.19
ΔV
O
Load regulation I
O
= 1 mA to 300 mA, V
O
≤ 2.5 V
T
J
= - 40 to 125 °C 0.005 0.01 %/mA
ΔV
O
Load regulation I
O
= 1 mA to 300 mA, V
O
≥ 2.5 V
T
J
= - 40 to 125 °C 0.0008 0.004 %/mA
ΔV
O
Output AC line regulation
(2)
V
I
= V
O(NOM)
+ 1 V, I
O
= 300 mA,
t
R
= t
F
= 30 µs 5mV
PP
I
Q
Quiescent current ON mode:
V
INH
= 1.4 V
I
O
= 0 85
µA
I
O
= 0, T
J
= - 40 to 125 °C 150
I
O
= 0 to 300 mA 200
I
O
= 0 to 300 mA, T
J
= - 40 to 125 °C 300
OFF mode: V
INH
= 0.4 V 0.003
T
J
= - 40 to 125 °C 1.5
V
DROP
Drop out voltage
(3)
I
O
= 1 mA 0.4
mV
I
O
= 1 mA, T
J
= - 40 to 125 °C 2
I
O
= 150 mA 60
I
O
= 150 mA, T
J
= - 40 to 125 °C 100
I
O
= 300 mA 150
I
O
= 300 mA, T
J
= - 40 to 125 °C 250
I
SC
Short-circuit current R
L
= 0 600 mA
SVR Supply voltage rejection
V
I
= V
O(NOM)
+ 0.25 V ±
V
RIPPLE
= 0.1 V, I
O
= 50 mA
For V
O(NOM)
< 2.5 V,
V
I
= 2.55 V
f = 1 kHz 55
dB
f = 10 kHz 50
DocID11039 Rev 9 7/21
LDS3985 Electri cal character istics
I
O(PK)
Peak output current V
O
≥ V
O(NOM)
- 5% 300 550 mA
V
INH
Inhibit input logic low V
I
= 2.5 V to 6 V, T
J
= - 40 to 125 °C 0.4 V
Inhibit input logic high 1.4
I
INH
Inhibit input current V
INH
= 0.4 V, V
I
= 6 V ±1 nA
eN Output noise voltage B
W
= 10 Hz to 100 kHz, C
O
= 2.2 µF 30 µV
RMS
t
ON
Turn-on time
(4)
C
BYP
= 33 nF 240 µs
T
SHDN
Thermal shutdown
(5)
160 °C
C
O
Output capacitor Capacitance 2.2 22 µF
ESR 5 5000 mΩ
1. For V
O(NOM)
< 2 V, V
I
= 2.5 V.
2. For V
O(NOM)
= 1.25 V, V
I
= 2.5 V.
3. Dropout voltage is the input-to-output voltage di fference at which the output volt age is 100 mV below its nominal value. This
specification does not apply to input voltages below 2.5 V.
4. Turn-on time is time measured between the enable input just exceeding V
INH
high value and the output voltage just
reaching 95% of its nominal value.
5. Typical thermal protection hysteresis is 20 °C.
Table 5. LDS3985 electrical characteristics (continued)
Symbol Parameter Test conditions Min. Typ. Max. Unit
Table 6. LDS3985 (automotive grade) electrical characteristics
Symbol Parameter Test conditions Min. Typ. Max. Unit
V
I
Operating input voltage 2.5 6 V
V
O
Output voltage < 2.5 V I
O
= 1 mA -50 50 mV
T
J
= - 40 to 85 °C -75 75
V
O
Output voltage ≥ 2.5 V I
O
= 1 mA -2 2 %
V
O(NO
M)
T
J
= - 40 to 85 °C -3 3
ΔV
O
Line regulation
(1)
V
I
= V
O(NOM)
+ 0.5 to 6 V,
T
J
= - 40 to 85 °C -0.1 0.1 %/V
V
O
= 4.7 to 5 V -0.19 0.19
ΔV
O
Load regulation I
O
= 1 mA to 300 mA, V
O
≤ 2.5 V
T
J
= - 40 to 85 °C 0.005 0.01 %/mA
ΔV
O
Load regulation I
O
= 1 mA to 300 mA, V
O
≥ 2.5 V
T
J
= - 40 to 85 °C 0.0008 0.004 %/mA
ΔV
O
Output AC line regulation
(2)
V
I
= V
O(NOM)
+ 1 V, I
O
= 300 mA,
t
R
= t
F
= 30 µs 5mV
PP
Ele ctrical characteristics LDS3985
8/21 DocID11039 Rev 9
I
Q
Quiesce nt current ON
mode: V
INH
= 1.4 V
I
O
= 0 85
µA
I
O
= 0, T
J
= - 40 to 85 °C 150
I
O
= 0 to 300 mA 200
I
O
= 0 to 300 mA, T
J
= - 40 to 85 °C 300
OFF mode: V
INH
= 0.4 V 0.003
T
J
= - 40 to 85 °C 1.5
V
DROP
Dropout voltage
(3)
I
O
= 1 mA 0.4
mV
I
O
= 1 mA, T
J
= -40 to 85 °C 2
I
O
= 150 mA 60
I
O
= 150 mA, T
J
= - 40 to 85 °C 100
I
O
= 300 mA 150
I
O
= 300 mA, T
J
= - 40 to 85 °C 250
I
SC
Short-circ uit cu rrent R
L
= 0 600 mA
SVR Supply voltage rejection
V
I
= V
O(NOM)
+ 0.25 V ±
V
RIPPLE
= 0.1 V, I
O
= 50 mA
For V
O(NOM)
< 2.5 V,
V
I
= 2.55 V
f = 1 kHz 55
dB
f = 10 kHz 50
I
O(PK)
Peak output cu rrent V
O
≥ V
O(NOM)
- 5% 300 550 mA
V
INH
Inhibit input logic low V
I
= 2.5 V to 6 V, T
J
= - 40 to 85 °C 0.4 V
Inhibit input logic high 1.4
I
INH
Inhibit input current V
INH
= 0.4 V, V
I
= 6 V ±1 nA
eN Output noise voltage B
W
= 10 Hz to 100 kHz, C
O
= 2.2 µF 30 µV
RMS
t
ON
Tu rn-on time
(4)
C
BYP
= 33 nF 240 µs
T
SHDN
Thermal shutdown
(5)
160 °C
C
O
Output capacitor Capacitance 2.2 22 µF
ESR 5 5000 mΩ
1. For V
O(NOM)
< 2 V, V
I
= 2.5 V.
2. For V
O(NOM)
= 1.25 V, V
I
= 2.5 V.
3. Dropout voltage is the input-to-output voltage dif ference at which the output voltage is 100 mV below its nominal value. This
specification does not apply to input voltages below 2.5 V.
4. Turn-on time is time measured between the enable input just exceeding V
INH
high value and the output voltage just
reaching 95% of its nominal value.
5. Typical thermal protection hysteresis is 20 °C.
Table 6. LDS3985 (automotive grade) electrical characteristics (continued)
Symbol Parameter Test conditions Min. Typ. Max. Unit
DocID11039 Rev 9 9/21
LDS3985 Typical performance characteristics
5 Typical performance characteristics
T
J
= 25 °C, V
I
= V
O(NOM)
+ 0.5 V, C
I
= 1 µF, C
O
= 2.2 µF, C
BYP
= 33 nF, I
O
= 1 mA, V
INH
= 1.4
V, unless otherwise specified.
Figure 3. Output voltage vs. temperature
V
0
=1.35 V Figure 4. Output voltage vs. temperature
V
0
=2.8 V
Figure 5. Output voltage vs. temperature
V
0
=3.3 V Figure 6. Inhibit voltage vs. temperatur e
V
0
=1.35 V
*/)*/)
Typical performance characteristics LDS3985
10/21 DocID11039 Rev 9
Figure 7. Inhibit voltage vs. temperature
(V
O
=3.3 V) Figure 8. Line regulation vs. temperature
(V
I
= 2.5 V to 6 V)
*/)*/)
Figure 9. Line regulation vs. temperature
(V
I
= 3.2 V to 6 V) Figure 10. Line regulation vs. temperature
(V
I
= 3.8 V to 6 V)
Figure 11. Quiescent current vs. temperature
(V
I
= 2.5 V) Figure 12. Quiescent current vs. temperature
(V
I
= 6 V)
DocID11039 Rev 9 11/21
LDS3985 Typical performance characteristics
Figure 13. Quiesce n t curr ent vs. temp era tur e
(V
I
= 3.4 V) Figure 14. Supply voltage rejection vs.
frequency
Figure 15. Dropout voltage vs. temperature Figure 16. Dropout voltage vs. output current
Figure 17. Inhibit transient
V
I
= 5 V, I
O
= 1 mA, V
INH
= 0 to 1.2 V, C
I
= C
O
= 1 µF (cer),
C
BYP
= 10 nF, T
R
= T
F
= 1 µs
Package mechanical data LDS3985
12/21 DocID11039 Rev 9
6 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.
Figure 18. SOT23-5L mechanical drawings
BN
DocID11039 Rev 9 13/21
LDS3985 Package mechanical data
Figure 19. SOT23-5L recommended footprint (dimensions in mm).
Table 7. SOT23-5L mechanical data
Dim. mm
Min. Typ. Max.
A0.90 1.45
A1 0 0.15
A2 0.90 1.30
b0.30 0.50
c2.09 0.20
D2.95
E1.60
e0.95
H2.80
L0.30 0.60
θ08
BN
Package mechanical data LDS3985
14/21 DocID11039 Rev 9
Figure 20. DFN6 (3 x 3 mm) drawings
B&
DocID11039 Rev 9 15/21
LDS3985 Package mechanical data
Table 8. DFN6 (3 x 3 mm) mechanical data
Dim. mm
Min. Typ. Max.
A0.80 1
A1 0 0.02 0.05
A3 0.20
b 0.23 0.45
D 2.90 3 3.10
D2 2.23 2.50
E 2.90 3 3.10
E2 1.50 1.75
0.95
L 0.30 0.40 0.50
Package mechanical data LDS3985
16/21 DocID11039 Rev 9
Figure 21. DFN6 footprint (dimensions in mm)
B&
DocID11039 Rev 9 17/21
LDS3985 Packaging mechanical data
7 Packaging mechanical data
Figure 22. Tape and reel SOT23-5L mechanical drawings
Table 9. Tape and reel SOT23-5L mechanical data
Dim. mm
Min. Typ. Max.
A180
C 12.8 13.0 13.2
D20.2
N60
T14.4
Ao 3.13 3.23 3.33
Bo 3.07 3.17 3.27
Ko 1.27 1.37 1.47
Po 3.9 4.0 4.1
P 3.9 4.0 4.1
Packagi ng mechan ic al data LDS3985
18/21 DocID11039 Rev 9
Figure 23. Tape for DFN6
B1
DocID11039 Rev 9 19/21
LDS3985 Packaging mechanical data
Figure 24. Reel for DFN6
Table 10. DFN6 tape and reel mechanical data
Dim. mm
Min. Typ. Max.
A0 3.20 3.30 3.40
B0 3.20 3.30 3.40
K0 1 1.10 1.20
B1
Revision history LDS3985
20/21 DocID11039 Rev 9
8 Revision history
Table 11. Document revision history
Date Revision Changes
02-Dec-20 04 1 First release.
10-Apr-2007 2 Added: new package TSOT23-5L.
16-May-2007 3 Added: new mechanical data DFN6D and order codes updated.
06-Sep-2007 4 Added: Table 1 in cover page.
11-Jun-2008 5 Modified: Table 10 on page 20.
11-Jul-2009 6 Modified: Table 10 on page 20.
29-Jul-2010 7 Modified: Table 1 on page 1 and Table 10 on page 20.
24-Oct-2013 8
Modified the Title and the Features in cover page.
Deleted Table1: Device summary.
Updated Table 10: Order codes and Section 6: Pack ag e mec han ic al data.
Added Table 6: LDS3985 (automotive grade) electrical characteristics and
Section 7: Packaging mechanical data.
Minor text changes.
28-Feb-2014 9
Part number LDS3985xx changed to LDS3985.
Updated the features, the description and Table 1 : Device summary in cover
page.
Updated Table 5: LDS39 85 ele ctrica l char acteristics, Table 6: LDS398 5
(automotive grade) electrical characteristics, Section 5: Typical performance
characteristics.
Minor text changes.
DocID11039 Rev 9 21/21
LDS3985
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