Diodes AP2004 User Manual
AP2004
PWM BUCK CONTROLLER
Features
• PWM Buck Control Circuitry
• Operating voltage can be up to 27V
• Under voltage Lockout (UVLO) Protection
• Short Circuit Protection (SCP)
• Soft-start circuit
• Variable Oscillator Frequency -- 300Khz Max
• 1.25V voltage reference Output
• 8-pin SOP package
• SOP-8L: Available in “Green” Molding Compound
(No Br, Sb)
• Lead Free Finish/ RoHS Compliant (Note 1)
Applications
• Backlight inverter
• LCD Monitor
• CDROM, XDSL Product
• DC/DC converters in computers, etc.
Ordering Information
AP 2004 S X - 13
General Description
The AP2004 integrates Pulse-Width-Modulation (PWM) control
circuit into a single chip, mainly designs for power-supply
regulator. All the functions include an on-chip 1.25V reference
output, an error amplifier, an adjustable oscillator, a soft-start,
UVLO, SCP circuitry, and a push-pull output circuit. Switching
frequency is adjustable by trimming CT. During low VCC situation,
the UVLO makes sure that the outputs are off until the internal
circuit operates normally.
Package PackingLead Free
S : SOP-8L
L : Lead Free
G : Green
Device
AP2004SL-13 S SOP-8L 2500/Tape & Reel -13
Lead-free
Package
Code
Packaging
(Note 2)
AP2004SG-13 S SOP-8L 2500/Tape & Reel -13
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html
2. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf
.
.
AP2004 Rev. 3 1 of 8 FEBRUARY 2009
www.diodes.com © Diodes Incorporated
13 : Tape & Reel
13” Tape and Reel
Quantity Part Number Suffix
Pin Assignments
( Top View )
AP2004
PWM BUCK CONTROLLER
OUT
VCC
COMP
FB
1
2
3
4
SOP-8L
8
GND
CT
7
6
SS
5
SCP
Pin Descriptions
Pin Name Description
CT Timing Capacitor
FB Voltage Feedback
SS Soft-Start.
COMP Feedback Loop Compensation
OUT PWM Output
GND Ground
VCC Supply Voltage
SCP Short Circuit Protection
AP2004 Rev. 3 2 of 8 FEBRUARY 2009
www.diodes.com © Diodes Incorporated
Block Diagram
AP2004
PWM BUCK CONTROLLER
FB
COMP
1.2 5V
Error Amplifier
VCC
Bandgap
Reference
1.5V
2.5V
Internal use
-
+
UVLO
Iss
SCP
0.7V
CT
SS
-
+
Oscillator
MAX. 300KHz
PWM Amplifier
+
+
-
GND
VCC
OUT
Absolute Maximum Ratings
Symbol Parameter Rating Unit
PD
Power dissipation at 25°C
600 mW
VCC Supply voltage 28 V
VI Amplifier input voltage 20 V
VO Collector output voltage VCC-1.0V V
I
Source current 200 mA
SOURCE
I
Sink current 200 mA
SINK
TOP Operating junction temperature range -20 to +125
T
Storage temperature range -65 to +150
ST
Recommended Operating Conditions
Symbol Parameter Min Max Unit
VCC Supply voltage 3.6 27 V
VI Amplifier input voltage 1.05 1.45 V
VO Collector output voltage Vcc-1.5 V
IFB Current into feedback terminal 45 µA
RF Feedback resistor 100 kΩ
CT Timing capacitor 100 6800 pF
F
Oscillator frequency 10 300 KHz
OSC
o
C
o
C
AP2004 Rev. 3 3 of 8 FEBRUARY 2009
www.diodes.com © Diodes Incorporated
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