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LD2985Bxx
Very low drop and low noise voltage regulator low ESR capacitors compatible, with inhibit function
Features
■Very low dropout voltage (280 mV at 150 mA and 7 mV at 1 mA load)
■Very low quiescent current (2 mA typ. at 150 mA load and 80 µA at no load)
■Output current up to 150 mA
■Logic controlled electronic shutdown
■Output voltage of 1.8, 2.5, 2.8, 3, 3.1, 3.3, 5 V
■Internal current and thermal limit
■Low output noise voltage 30 mVrms
■Smallest package SOT23-5L
■Temperature range: - 40°C to 125 °C
Description
The LD2985Bxx is a 150 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. An external capacitor, CBYP = 10 nF, connected
SOT23-5L
between bypass pin and GND reduce the noise to 30 µVrms. Typical application are in cellular phone, palmtop laptop computer, personal digital assistant (PDA), personal stereo, camcorder and camera.
Table 1. |
Device summary |
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Part numbers |
Order codes |
Output voltages |
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LD2985BXX18 |
LD2985BM18R |
1.8 V |
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LD2985BXX25 |
LD2985BM25R |
2.5 V |
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LD2985BXX28 |
LD2985BM28R |
2.8 V |
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LD2985BXX30 |
LD2985BM30R |
3.0 V |
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LD2985BXX31 |
LD2985BM31R |
3.1 V |
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LD2985BXX33 |
LD2985BM33R |
3.3 V |
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LD2985BXX50 |
LD2985BM50R |
5.0 V |
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February 2012 |
Doc ID 8189 Rev 12 |
1/18 |
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www.st.com |
Contents |
LD2985Bxx |
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Contents
1 |
Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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Application notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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6.1 |
External capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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6.2 |
Input capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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6.3 |
Output capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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6.4 |
Important . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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6.5 |
Inhibit input operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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6.6 |
Reverse current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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Doc ID 8189 Rev 12 |
LD2985Bxx |
Diagram |
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1 Diagram
Figure 1. Schematic diagram
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Pin configuration |
LD2985Bxx |
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2 Pin configuration
Figure 2. Pin connections (top view)
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1 |
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2 |
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3 |
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SC12360 |
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Table 2. |
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Pin description |
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Pin n° |
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Symbol |
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Name and function |
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1 |
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IN |
Input port |
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2 |
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GND |
Ground pin |
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Control switch ON/OFF. Inhibit is not internally pulled-up; it cannot be left |
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3 |
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INHIBIT |
floating. Disable the device when connected to GND or to a positive |
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voltage less than 0.18V |
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4 |
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Bypass |
Bypass pin: capacitor to be connected to GND in order to improve the |
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thermal noise performances |
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5 |
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OUT |
Output port |
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Table 3. |
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Thermal data |
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Symbol |
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Parameter |
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Value |
Unit |
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RthJC |
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Thermal resistance junction-case |
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81 |
°C/W |
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RthJA |
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Thermal resistance junction-ambient |
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255 |
°C/W |
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Doc ID 8189 Rev 12 |
LD2985Bxx |
Maximum ratings |
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3 Maximum ratings
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Table 4. |
Absolute maximum ratings |
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Symbol |
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Parameter |
Value |
Unit |
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VI |
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DC input voltage |
16 |
V |
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VINH |
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INHIBIT input voltage |
16 |
V |
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IO |
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Output current |
Internally limited |
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PD |
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Power dissipation |
Internally limited |
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TSTG |
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Storage temperature range |
-65 to 150 |
°C |
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TOP |
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Operating junction temperature range |
-40 to 125 |
°C |
Note: |
Absolute maximum ratings are those values beyond which damage to the device may occur. |
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Functional operation under these condition is not implied. |
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Doc ID 8189 Rev 12 |
5/18 |
Electrical characteristics |
LD2985Bxx |
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4 Electrical characteristics
TJ = 25 °C, VI = VO + 1 V, IO = 50 mA, VINH= 2 V, CI = CO = 1 µF, unless otherwise specified.
Table 5. |
Electrical characteristics |
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Symbol |
Parameter |
Test conditions |
Min. |
Typ. |
Max. |
Unit |
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VOP |
Operating input voltage |
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2.5 |
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16 |
V |
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VI = 2.5V |
1.463 |
1.5 |
1.537 |
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VO |
Output voltage |
IO = 1 to 150mA |
1.455 |
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1.545 |
V |
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IO = 1 to 150mA, TJ= -40 to 125°C |
1.440 |
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1.560 |
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VI = 2.8V |
1.755 |
1.8 |
1.845 |
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VO |
Output voltage |
IO = 1 to 150mA |
1.746 |
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1.854 |
V |
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IO = 1 to 150mA, TJ= -40 to 125°C |
1.728 |
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1.872 |
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VI = 3.5V |
2.437 |
2.5 |
2.562 |
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VO |
Output voltage |
IO = 1 to 150mA |
2.425 |
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2.575 |
V |
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IO = 1 to 150mA, TJ= -40 to 125°C |
2.4 |
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2.6 |
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VI = 3.5V |
2.633 |
2.7 |
2.767 |
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VO |
Output voltage |
IO = 1 to 150mA |
2.619 |
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2.781 |
V |
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IO = 1 to 150mA, TJ= -40 to 125°C |
2.592 |
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2.808 |
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VI = 3.8V |
2.73 |
2.8 |
2.87 |
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VO |
Output voltage |
IO = 1 to 150mA |
2.716 |
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2.884 |
V |
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IO = 1 to 150mA, TJ= -40 to 125°C |
2.688 |
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2.912 |
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VI = 3.85V |
2.779 |
2.85 |
2.921 |
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VO |
Output voltage |
IO = 1 to 150mA |
2.764 |
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2.935 |
V |
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IO = 1 to 150mA, TJ= -40 to 125°C |
2.736 |
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2.964 |
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VI = 4.0V |
2.925 |
3.0 |
3.075 |
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VO |
Output voltage |
IO = 1 to 150mA |
2.91 |
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3.09 |
V |
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IO = 1 to 150mA, TJ= -40 to 125°C |
2.88 |
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3.12 |
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VI = 4.1V |
3.023 |
3.1 |
3.177 |
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VO |
Output voltage |
IO = 1 to 150mA |
3.007 |
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3.193 |
V |
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IO = 1 to 150mA, TJ= -40 to 125°C |
2.976 |
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3.224 |
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VI = 4.2V |
3.120 |
3.2 |
3.28 |
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VO |
Output voltage |
IO = 1 to 150mA |
3.104 |
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3.296 |
V |
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IO = 1 to 150mA, TJ= -40 to 125°C |
3.072 |
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3.328 |
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VI = 4.3V |
3.218 |
3.3 |
3.382 |
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VO |
Output voltage |
IO = 1 to 150mA |
3.201 |
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3.399 |
V |
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IO = 1 to 150mA, TJ= -40 to 125°C |
3.168 |
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3.432 |
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VI = 4.5V |
3.413 |
3.5 |
3.587 |
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VO |
Output voltage |
IO = 1 to 150mA |
3.395 |
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3.605 |
V |
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IO = 1 to 150mA, TJ= -40 to 125°C |
3.360 |
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3.640 |
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Doc ID 8189 Rev 12 |
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