Datasheet

UNISONIC TECHNOLOGIES CO., LTD
LD2127/A
Preliminary
LINEAR INTEGRATED CIRCUIT
LOW DROP FIXED AND
ADJUSTABLE POSITIVE
VOLTAGE REGULATORS

DESCRIPTION
1
The UTC LD2127/A is a low dropout, 3-terminal positive
voltage regulator designed to provide output current up to
800mA/1A, There are adjustable versions (VREF=1.0V) and
various fixed versions.

SOT-223
FEATURES
* Low dropout voltage
* Suitable for SCSI-2 active termination if VOUT set to 2.85V
* Output current up to 0.8A for 2127 and 1.0A for 2127A
* Built-in current limit and over temperature protection
* Ultra low Adjustment Current (7μA typ.)
* Ultra low minimum Load (0.3mA typ.)
* Stable with low ESR ceramic output capacitor (MLCC)

ORDERING INFORMATION
Lead Free
Ordering Number
Halogen Free
LD2127L-xx-AA3--R
Note: Pin Assignment: I: VIN
LD2127G-xx-AA3--R
O: VOUT
Package
SOT-223

Pin Assignment
A: AOI
B: OAI
C: AIO
D: IAO
Packing
Tape Reel
A: ADJ
LD2127 1 L-xx-AA3- 2 - R
(1)Packing Type
(1) R: Tape Reel
(2)Pin Assignment
(2) refer to Pin Assignment
(3)Package Type
(3) AA3: SOT-223
(4)Output Voltage Code
(4) xx: refer to Marking Information
(5)Lead Free
(5) L: Lead Free, G: Halogen Free
(6)Current Code
(6) Blank: 800mA, A: 1A
www.unisonic.com.tw
Copyright © 2013 Unisonic Technologies Co., Ltd
1 of 6
QW-R102-054.a
LD2127/A

Preliminary
LINEAR INTEGRATED CIRCUIT
MARKING INFORMATION
PACKAGE
VOLTAGE CODE
MARKING
Current Code
SOT-223
AD :ADJ
Voltage Code
1

L: Lead Free
G: Halogen Free
Pin Code
LD2127
XX
2
Date Code
3
BLOCK DIAGRAM
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
2 of 6
QW-R102-054.a
LD2127/A

Preliminary
LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIMUM RATING (TA=25°C)
PARAMETER
SYMBOL
RATINGS
UNIT
DC Input Voltage
VIN
18
V
Power Dissipation
PD
Internally limited
W
Junction Temperature
TJ
+150
°C
Storage temperature
TSTG
-65 ~ +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.

RECOMMENDED OPERATING RATINGS
PARAMETER
Input Voltage
Operating Junction Temperature

RATINGS
15
0 ~ +125
UNIT
V
°C
SYMBOL
θJA
θJC
RATINGS
165
15
UNIT
°C/W
°C/W
THERMAL DATA
PARAMETER
Junction to Ambient
Junction to Case

SYMBOL
VIN
TJ
ELECTRICAL CHARACTERISTICS
(TA=25°C, refer to the test circuits, TJ=0 ~ 125°C, CO=10μF unless otherwise specified)
For LD2127/A-ADJ
PARAMETER
Reference Voltage
SYMBOL
TEST CONDITIONS
VREF VIN-VOUT=2V, IOUT=10mA, TJ=25°C
VIN-VOUT=1.4~10V
Reference Voltage
VREF
LD2127A : IOUT=10~1000mA
Line Regulation
∆VOUT VIN-VOUT=1.5 ~ 13.75V, IOUT=10mA
VIN-VOUT=3V
Load Regulation
∆VOUT LD2127 : IOUT=10~800mA
LD2127A : IOUT=10~1000mA
Temperature stability
∆VOUT
Long Term Stability
∆VOUT 1000 hrs, TJ=125°C
Operating Input Voltage
VIN
Adjustment Pin Current
IADJ
VIN15V
VIN-VOUT=1.4~10V,
Adjustment Pin Current Change
∆IADJ
LD2127A : IOUT=10 ~ 1000mA
Minimum Load Current
IO(MIN) VIN=15V
LD2127
Current Limit
ILIMIT VIN-VOUT=5V, TJ=25°C
LD2127A
Output Noise (%VO)
eN
B=10Hz ~ 10KHz, TJ=25°C
IOUT=40mA, f=120Hz, TJ=25°C,
Supply Voltage Rejection
SVR
VIN-VOUT=3V, VRIPPLE=1VPP
IOUT=100mA
IOUT=500mA
Dropout Voltage
VD
IOUT=800mA
IOUT=1A
Thermal Regulation
TA=25°C, 30ms Pulse
Thermal Shutdown
OTP
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
MIN
0.98
TYP
1.0
MAX
1.02
UNIT
V
0.98
1.0
1.02
V
0.5
%
2.0
%
0.50
0.3
7
15
10
%
%
V
μA
0.3
2
μA
0.3
1
mA
800
1000
mA
0.003
%
75
dB
1.05
1.15
1.18
1.22
0.01
150
1.15
1.25
1.28
1.35
0.10
V
%/W
°C
3 of 6
QW-R102-054.a
LD2127/A

Preliminary
LINEAR INTEGRATED CIRCUIT
APPLICATION NOTE of LD2127/A ADJUSTABLE
The LD2127/A adjustable has a reference voltage of between the OUT and ADJ pins. IADJ is 7μA typ. (10μA
max.) and IADJ is 0.3μA typ. (2µA max.).
R1 is normally fixed to 1.2kΩ.
From figure 1 we obtain:
VOUT=VREF+R2(IADJ+IR1)=VREF + R2(IADJ+VREF/R1)=VREF(1+R2/R1) + R2 × IADJ.
Usually R2 value is in the range of few KΩ, so the R2 X IADJ product could be neglected; then the above
expression becomes: VOUT=VREF(1+R2/R1)
For better load regulation, realize a good Kelvin connection of R1 and R2 is important. Particularly R1 connection
must be realized very close to OUT and ADJ pin, while R2 ground connection must be placed as near as possible to
the negative Load pin. Ripple rejection can be improved by introducing a 10μF electrolytic capacitor placed in
parallel to the R2 resistor (See Fig. 2)
The UTC LD2127/A also supports MLCC. See Fig.3 for adjustable output.
UTC LD2127/A
VIN
IN
+
OUT
ADJ
10µF
VOUT
+
10µF
R1
1.2kΩ
VREF
R2
Fig.1 Adjustable Output Voltage Application Circuit
Fig.2 Adjustable Output Voltage Application with improved Ripple Rejection.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
4 of 6
QW-R102-054.a
LD2127/A

Preliminary
LINEAR INTEGRATED CIRCUIT
APPLICATION NOTE of LD2127/A ADJUSTABLE(Cont.)
UTC LD2127/A
VIN
IN
10µF
VOUT
OUT
ADJ
10µF
R1
1.2kΩ
VREF
R2
Fig.3 Adjustable Output Voltage Application Circuit for MLCC
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
5 of 6
QW-R102-054.a
LD2127/A
Preliminary
LINEAR INTEGRATED CIRCUIT
TYPICAL CHARACTERISTICS
Power (W)

UTC assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or
other parameters) listed in products specifications of any and all UTC products described or contained
herein. UTC products are not designed for use in life support appliances, devices or systems where
malfunction of these products can be reasonably expected to result in personal injury. Reproduction in
whole or in part is prohibited without the prior written consent of the copyright owner. The information
presented in this document does not form part of any quotation or contract, is believed to be accurate
and reliable and may be changed without notice.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
6 of 6
QW-R102-054.a