UNISONIC TECHNOLOGIES CO., LTD
LD1985
VERY LOW DROP AND LOW
NOISE VOLTAGE REGULATOR
LOW ESR CAP. COMPATIBLE,
WITH INHIBIT FUNCTION
DESCRIPTION
LINEAR INTEGRATED CIRCUIT
The UTC
LD1985
is a 150mA 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 1μA
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
=10nF, connected between bypass pin
and GND reduce the noise to 30μVrms.
Typical application is in cellular phone, palmtop laptop computer,
personal digital assistant (PDA), personal stereo, camcorder and
camera.
FEATURES
* Very Low Dropout Voltage (280mV at 150mA and 7mV at 1mA Load)
* Very Low Quiescent Current
* Output Current up to 150mA
* Logic Controlled Electronic Shutdown
* Output Voltage of 1.5, 1.8, 2.5, 2.8, 2.85, 3, 3.1, 3.2, 3.3, 3.5, 3.6, 3.8,
4, 4.7, 5V
* Internal Current and Thermal Limit
* Low Output Noise Voltage 30μVrms
ORDERING INFORMATION
Ordering Number
Package
SOT-25
Packing
Tape Reel
Lead Free
Halogen Free
LD1985L-xx-AF5-R
LD1985G-xx-AF5-R
Note: xx: Output Voltage, refer to Marking Information.
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QW-R102-021.H
LD1985
MARKING INFORMATION
PACKAGE
VOLTAGE CODE
15:1.5V
18:1.8V
25:2.5V
28:2.8V
2J:2.85V
30:3.0V
31:3.1V
32:3.2V
33:3.3V
35:3.5V
36:3.6V
38:3.8V
40:4.0V
47:4.7V
50:5.0V
LINEAR INTEGRATED CIRCUIT
MARKING
SOT-25
PIN CONFIGURATION
PIN DESCRIPTION
PIN NAME
V
IN
GND
INHIBIT
Bypass
V
OUT
DESCRIPTION
Input port
Ground Pin
Control switches 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
Bypass pin: capacitor to be connected to GND in order to improve the thermal noise
performances.
Output port
PIN NO.
1
2
3
4
5
BLOCK DIAGRAM
V
IN
CURRENT
LIMIT
V
OUT
INHIBIT
START-UP
SHUTDOWN
REFERENCE
VOLTAGE
ERROR
AMPLIFIER
DRIVER
BYPASS
TERM. PROTEC.
GND
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QW-R102-021.H
LD1985
ABSOLUTE MAXIMUM RATINGS
(T
A
=25°C)
PARAMETER
LINEAR INTEGRATED CIRCUIT
SYMBOL
RATINGS
UNIT
DC Input Voltage
V
IN
7
V
INHIBIT Input Voltage
V
INH
7
V
Output Current
I
OUT
Internally limited
Power Dissipation
P
D
Internally limited
Operating Junction Temperature
T
OPR
-40 ~ +85
°C
Storage Temperature
T
STG
-40 ~ +150
°C
Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.
THERMAL DATA
PARAMETER
SYMBOL
θ
JC
RATINGS
81
UNIT
°C/W
Junction to Case
ELECTRICAL CHARACTRISTICS
MAX
7
1.530
1.545
1.836
1.854
2.550
2.575
2.856
2.884
2.907
2.936
3.060
3.090
3.162
3.193
3.264
3.296
3.366
3.399
3.570
3.605
3.672
3.708
3.876
3.914
4.080
4.120
4.794
4.841
5.100
5.150
UNIT
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
(T
J
=25°C, V
IN
=V
OUT
+1V, I
OUT
=1mA, V
SHDN
=2V, C
I
=1μF, C
O
=1μF, unless otherwise specified)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
Operating Input Voltage
V
I(OPR)
2.5
V
IN
=2.5V
1.470
1.5
I
OUT
=1 ~ 150mA
1.455
V
IN
=2.8V
1.764
1.8
I
OUT
=1 ~ 150mA
1.746
V
IN
=3.5V
2.450
2.5
I
OUT
=1 ~ 150mA
2.425
V
IN
=3.8V
2.744
2.8
I
OUT
=1 ~ 150mA
2.716
V
IN
=3.85V
2.793
2.85
I
OUT
=1 ~ 150mA
2.764
V
IN
=4.0V
2.940
3.0
I
OUT
=1 ~ 150mA
2.910
V
IN
=4.1V
3.038
3.1
I
OUT
=1 ~ 150mA
3.007
V
IN
=4.2V
3.136
3.2
Output Voltage
V
OUT
I
OUT
=1 ~ 150mA
3.104
V
IN
=4.3V
3.234
3.3
I
OUT
=1 ~ 150mA
3.201
V
IN
=4.5V
3.430
3.5
I
OUT
=1 ~ 150mA
3.395
V
IN
=4.6V
3.528
3.6
I
OUT
=1 ~ 150mA
3.492
V
IN
=4.8V
3.724
3.8
I
OUT
=1 ~ 150mA
3.686
V
IN
=5.0V
3.920
4
I
OUT
=1 ~ 150mA
3.880
V
IN
=5.7V
4.606
4.7
I
OUT
=1 ~ 150mA
4.559
V
IN
=6.0V
4.900
5
I
OUT
=1 ~ 150mA
4.850
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PCB Design
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