HOLTEK HT1087 User Manual
0.5A General Purpose LDO
Features
·
Output voltage ranges: Fixed range of 1.5V, 1.8V,
2.5V, 3.3V, 5.0V or adjustable type.
·
High accuracy: ±2%
·
Low voltage drop: 1.1V (typ.), V
Applications
·
Active SCSI terminations
·
Post regulator for switching power supplies
·
Low voltage microcontrollers
General Description
The HT1087 devices are a series of three-terminal high
current low voltage regulators. They can deliver an out
put current of 0.5A and can accept input voltages up to
12V. The devices are available in both adjustable and
=5.0V at 0.5A
OUT
HT1087 Series
·
Guaranteed output current: 0.5A
·
Low quiescent current: 8mA (typ.)
·
Integrated current limit & thermal protection circuits
·
SOT89, TO92 packages
·
Motherboard clock supplies
·
Battery chargers
fixed output voltage type with a range of 1.5V to 5.0V. In
ternal current limit and thermal protection circuits pro
vide protection against overload conditions that could
create excessive junction temperatures.
-
-
Selection Table
Part No. Output Voltage Package Marking
HT1087-ADJ Adjust
HT1087-15 1.5V
HT1087-18 1.8V
HT1087-25 2.5V
HT1087-33 3.3V
HT1087-50 5.0V
Note:
For lead free devices, a ²#² mark is suffixed at the end of the date code.
Block Diagram
V
I N
C u r r e n t
L i m i t i n g
A m p l i f i e r
T h e r m a l
P r o t e c t i o n
V
O U T
SOT89
TO92
HT1087-ADJ
HT1087-15
HT1087-18
HT1087-25
HT1087-33
HT1087-50
E r r o r
A m p .
Rev. 1.10 1 October 5, 2007
B a n d g a p
R e f e r e n c e
A D J
G N D
Pin Assignment
HT1087 Series
S O T 8 9
T o p V i e w
V I N
G N D /
A D J
G N D /
A D J
H T 1 0 8 7 - X X
V O U T
V O U T V I N
Absolute Maximum Ratings*
Input Supply Voltage ..................VSS-0.3V to VSS+13V
T O 9 2
H T 1 0 8 7 - X X
V O U T
G N D / A D J
V O U T
G N D / A D J
F r o n t V i e w
V I N
B o t t o m V i e w
V I N
Storage Temperature ...........................-50°Cto125°C
Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maximum Ratings² may
cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed
in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability.
²*² Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits.
The guaranteed specifications apply only for the test conditions listed.
Recommended Operating Conditions
Input Supply Voltage ..................VSS-0.3V to VSS+12V
Ambient Temperature ............................-40°Cto85°C
Thermal Information
Symbol Parameter Package Max. Unit
Thermal Resistance
q
JA
(Junction to Ambient)
(Assume no ambient airflow,
no heat sink)
P
D
Power Dissipation
Note: PDis measured at Ta= 25°C
SOT-89
TO-92 200
SOT-89 0.5 W
TO-92 0.5 W
200
°C/W
°C/W
Rev. 1.10 2 October 5, 2007
HT1087 Series
Electrical Characteristics
TJ=25°C, VIN=V
+1.5V, IO=10mA, unless otherwise specified (see note 1)
OUT
Symbol Parameter Test Conditions Min. Typ. Max. Unit
V
REF
Reference Voltage
2.75V £ V
IN
£ 12V
1.225 1.250 1.275 V
HT1087-15 1.470 1.500 1.530 V
HT1087-18 1.764 1.800 1.836 V
V
OUT
Output Voltage
HT1087-25 2.450 2.500 2.550 V
HT1087-33 3.234 3.300 3.366 V
HT1087-50 4.900 5.000 5.100 V
=0.5A
DV
DV
V
I
LIMIT
I
ADJ
I
SS
LOAD
LINE
DIF
Load Regulation (see note 2)
Line Regulation
Dropout Voltage (see note 3)
Current Limit (see note 4)
Adjust Pin Current
(Variable Version)
Quiescent Current
(Fixed Version)
RR Ripple Rejection
V
D
O U T
T
D
Temperature Coefficient
a
I
OUT
2.75V £ V
DV
OUT
DV
OUT
2.75V £ V
2.75V £ V
£ 12V ¾
IN
=2%, I
=0.5A ¾
OUT
=10%
£ 12V
IN
£ 12V
IN
120Hz input ripple
=22mF
C
OUT
-40°C<Ta<85°C ¾±0.4 ¾ mV/°C
1
¾
0.015 0.15 %/V
1.1 1.3 V
0.5 1.5
¾
55 120
¾
¾
60
20 mV
¾
813mA
¾
A
mA
dB
Note:
1. Specifications are production tested at room temperature, Ta. Specifications within the -40°Cto85°C
operating temperature range are assured by design, characterization and correlation withStatistical Quality
Controls (SQC).
2. Loadregulation is measured at a constant junction temperature, using pulse testing with a low ON time and
is guaranteed up to the maximum power dissipation. Power dissipation is determined by the input/output
differential voltage and the output current. Guaranteed maximum power dissipation will notbe available over
the full input/output range. The maximum allowable power dissipation at any ambient temperature is
=(T
P
D
J(MAX)
- Ta ) / qJA.
3. Dropoutvoltage is defined as the input voltage minus the output voltage that produces a 2% change inthe
output voltage from the value at V
IN=VOUT
+1.5V with a fixed load.
4. Current limit is measured by pulsing for a short time.
Rev. 1.10 3 October 5, 2007
Application Circuits
Basic Circuits
·
Variable voltage type
HT1087 Series
V
I N
C 1
1 0
m
C o m m o n C o m m o n
Note:
C1 isrequired if the needed if the device is located far from filter capacitors, the recommended value is 10mF.
V I N
H T 1 0 8 7 - A D J
F
V=V(1+
OUT REF ADJ
A D J
I
A D J
V O U T
V
R2
)+I R2
R1
R E F
S i n g l e p o i n t G N D
R 1
1 2 5
W
R 2
1 k
W
V
O U T
C 2
1 0
F
m
C2 is required for stability, the recommended value is 10mF.
R1 is required for regulation, the recommended value is 125W.
·
Fixed voltage type
V
I N
V I N
H T 1 0 8 7
V O U T
V
O U T
S e r i e s
C 1
F
1 0
m
G N D
C 2
F
1 0
m
C o m m o n C o m m o n
Note:
C1 isrequired if the needed if the device is located far from filter capacitors, the recommended value is 10mF.
S i n g l e p o i n t G N D
C2 is required for stability, the recommended value is 10mF.
Typical Application Circuits
·
1.25~10.5V regulator
2 . 7 5 V£V
C o m m o n C o m m o n
1 2 V
I N
£
C 1
1 0
m
V I N
H T 1 0 8 7 - A D J
F
V=V(1+
OUT REF ADJ
A D J
I
A D J
V O U T
V
R2
)+I R2
R1
R E F
S i n g l e p o i n t G N D
R 1
1 2 5
W
R 2
1 k
W
V
O U T
C 2
1 0
F
m
Rev. 1.10 4 October 5, 2007
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