LD2985
Very low drop and low noise voltage regulator with inhibit function
Datasheet
-
production data
Description
The LD2985 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, C
BYP
= 10 nF, connected
between bypass pin and GND reduces 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
Order codes
LD2985BM18R
LD2985BM25R
LD2985BM28R
LD2985BM30R
LD2985BM31R
LD2985BM33R
LD2985BM50R
Output voltages
1.8 V
2.5 V
2.8 V
3.0 V
3.1 V
3.3 V
5.0 V
SOT23-5L
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
Small package SOT23-5L
Temperature range: - 40°C to 125 °C
February 2019
This is information on a product in full production.
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Contents
LD2985
Contents
1
2
3
4
5
6
Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Application notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.1
6.2
6.3
6.4
6.5
6.6
External capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Input capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Output capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Important . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Inhibit input operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Reverse current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7
8
9
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Packaging mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
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LD2985
Diagram
1
Diagram
Figure 1. Schematic diagram
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Pin configuration
LD2985
2
Pin configuration
Figure 2. Pin connections (top view)
5
4
1
2
3
SC12360
Table 2. Pin description
Pin n°
1
2
3
Symbol
IN
GND
INHIBIT
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 0.18 V
Bypass pin: capacitor to be connected to GND in order to improve the
thermal noise performances
Output port
Name and function
4
5
Bypass
OUT
Table 3. Thermal data
Symbol
R
thJC
R
thJA
Parameter
Thermal resistance junction-case
Thermal resistance junction-ambient
Value
81
255
Unit
°C/W
°C/W
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LD2985
Maximum ratings
3
Maximum ratings
Table 4. Absolute maximum ratings
Symbol
V
I
V
INH
I
O
P
D
T
STG
T
OP
DC input voltage
INHIBIT input voltage
Output current
Power dissipation
Storage temperature range
Operating junction temperature range
Parameter
Value
-0.3 to 16
-0.3 to 16
Internally limited
Internally limited
-65 to 150
-40 to 125
°C
°C
Unit
V
V
Note:
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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