ACUTECH AQ120EX

AQ120
LDO Regulator Controller
SOT23-5 Package
Preliminary Specification
Revision 1.2
General Description
The AQ120 is a low cost LDO controller.
The AQ120 flexibility allows the setting of
the output voltage and controls up to 2
Amps of output current with a minimum
number of external components.
April 1, 2006
Applications
• Graphic cards
• PC motherboards
• Switching power supply post-regulation
• Telecom equipment
• DVD video player
The open collector output is capable of
driving an external PNP transistor. A
temperature stable bandgap reference
(1.25 V) controls the output voltage and
is programmable through two external
resistors. The AQ120 if offered in the
very small SOT23-5 package.
Features
• 1.25V reference with 1.5% accuracy
• Low current consumption
• Offered in small SOT23-5 package
• Wide Vin range: 2.5V to 18V
• 20mA drive current sink
• RoHS compliant available
Block Diagram
Pin Configuration
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AQ120
AQ120
Acutechnology Semiconductor Inc.
Typical Application
Note: The values of R1and R2 set the output voltage. The typical Vref is 1.25V
Pin Descriptions
Pin
Pin Name
Function
1
DRIVE
2
GND
3
GND BIAS
4
VCC
Positive supply
5
VREF
Voltage programming pin; has a threshold of 1.25V.
Output of error amplifier. 20 mA sink capability to drive PNP pass element
Ground
Must connect to GND for proper operation as an LDO Controller
Ordering Information
Device
Operating Tj
%Tol
Pkg Type
VOUT
Wrap
Order Number
AQ120
-40C˚ ≤ 85C˚
1.5
SOT-23-5
1.25V
T&R
AQ120EX-M5-AJ-TR
AQ120
-40C˚ ≤ 85C˚
1.5
SOT-23-5
1.25V
T&R
AQ120EX-M5-AJ-TRL
Note: The
TRL parts are Lead Free and RoHS compliant.
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2
Rev. 1.2
April 1, 2006
AQ120
Acutechnology Semiconductor Inc.
Absolute Maximum Ratings
Parameter
Value
Units
VCC Voltage
18
V
DRIVE Voltage
18
V
REF Voltage
18
V
VCC, DRIVE, REF Current
50
mA
Operating Junction Temperature
150
ºC
Lead Temperature (soldering 10 seconds)
300
ºC
-80 to +150
ºC
Storage Temperature Range
Electrical Specifications
Electrical characteristics are guaranteed over the full temperature range –40ºC <Tj< 85ºC. Ambient
temperature must be de-rated based upon power dissipation and package thermal characteristics.
Unless otherwise stated, test conditions are VCC = 5V, VDRIVE = 4.3V, VGND BIAS = GND.
Symbol
Parameter
Conditions
Vcc
Supply Voltage Range
Icc
Vcc Quiescent Supply
Current
VREF= VCC= VDRIVE= 5V
Reference Voltage
Ta=25ºC
VREF
Min
Typ
Max
Units
2.5
5
18
V
150
300
µA
1.250
1.268
V
1.231
Reference Temperature
Deviation
Output variation with Supply
Voltage
Vref variation with Drive
Current
-40ºC <Tj<85ºC
0.5
1
%
VCC=2.5V to 18V
IDRIVE = 500 µA
0.3
1.0
mV/V
IDRIVE = 0.1mA to 10 mA
0.15
0.20
%/mA
Reference input current
VREF = 0V
Output Saturation Voltage
IDRIVE = 10 mA, VREF = 0V
I DRIVE
Drive Current
V DRIVE = 5V,
VREF = VGND BIAS = GND
I LEAK
Output Leakage Current
VDRIVE = VREF = VCC = 18V
TC REF
LnREG
LdREG
I REF
VDRVlow
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-50
3
-20
1.8
20
nA
2.2
25
200
Rev. 1.2
V
mA
400
nA
April 1, 2006
AQ120
Acutechnology Semiconductor Inc.
APPLICATION
(Figure 1)
GENERAL DESCRIPTION
The AQ120 is a linear LDO voltage regulator controller. It drives a discrete PNP transistor while
comparing the output to a 1.25V reference. The output voltage is programmable through an external
resistor divider. VOUT can be set to any value above 1.25 Volts. The collector of the external PNP
transistor provides the output current to the load. Vin range is 2.5V to 18V. The Maximum Load current
is Beta of the PNP times IDRIVE. IDRIVE range is 0.1 mA to 20 mA (max).
SETTING THE OUTPUT VOLTAGE
The AQ120 VREF pin is the input to an amplifier comparing to a precision 1.25V reference.
With VREF tied back to the output, it will drive the base of the external PNP to maintain output voltage
with changing load current and VCC. The regulated output voltage can be set by selecting the proper
ratio of R1 and R2.
The Output Voltage is set by:
Vout = VREF ∗
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(
R1 + R 2
= 1.25V ∗ 1 + R1
R2
R2
4
)
Rev. 1.2
April 1, 2006
AQ120
Acutechnology Semiconductor Inc.
SELECTION OF PNP PASS DEVICE
In the application of (figure 1) above, an FMMT549 SOT223 package was used.
However, selection of the PNP pass device is based on Vin max, Iout max, and Power dissipation for
your particular application.
VIN max
BVCEO and BVCBO minimum rating of the PNP transistor must exceed the maximum Vin of the
application. The AQ120 will stand off 18V max. Therefore the maximum voltage the PNP will
experience is 18V.
Iout max
Beta of the PNP transistor will dictate the maximum output current as per the equation:
Iout max = Idrive max(20mA) ∗ BetaExt.PNP
Higher beta of the PNP will improve the Vout variation due to change in load (load reg.) Minimizing the
Idrive required will also minimize the Load reg. as Vout will decrease by .15% per mA of Idrive.
Therefore, delta 10mA of Idrive will cause a delta 1.5% of Vout.
Power dissipation
Selection of the external PNP package is based on size requirements and power dissipation. Consult
the transistor data sheet for power considerations.
Contact Information
Acutechnology Semiconductor Inc.
3487 McKee Rd. Suite 52
San Jose CA , USA 95127
TEL:
FAX:
website:
(408) 259-2300
(408) 259-9160
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Disclaimer
The information furnished by Acutechnology in this data sheet is believed to be accurate and reliable. However,
Acutechnology assumes no responsibility for its use. Acutechnology reserves the right to change circuitry and specifications
at any time without notification to the customer.
Life Support Policy
Acutechnology Products are not designed or authorized for use as components in life support devices or systems where
malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are
devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to
perform can be reasonably expected to result in a significant injury to the user.
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Rev. 1.2
April 1, 2006
AQ120
Acutechnology Semiconductor Inc.
Package Dimensions
SOT23-3, SOT23-4, SOT23-5, SOT23-6
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6
Rev. 1.2
April 1, 2006