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AP2003
Synchronous PWM Controller Features
- Single or Dual Supply Application - 0.8V + 1.0% Voltage Reference. - Fast transient response. - Synchronous operation for high efficiency (95%) - Soft Start functions - Small size with minimum external components - Industrial temperature range - Under Voltage Lockout function - SOP-8L package
(Preliminary) General Description
The AP2003 is a low-cost, full featured, and synchronous voltage-mode controller designed for use in single ended power supply applications where efficiency is of the primary concern. This synchronous operation allows the elimination of heat sinks in many applications. The AP2003 is ideal for implementing DC/DC converters needed to power advanced microprocessors in low cost systems, or in distributed power applications where efficiency is important. Internal level-shift, high-side drive circuitry, and preset shoot-thru control, allows the use of inexpensive N-channel power switches. AP2003 features include temperature compensated voltage reference, an internal 200KHz virtual frequency oscillator, under-voltage lockout protection, soft-start, and shutdown function.
Applications
- Microprocessor core supply - Low cost synchronous applications - Voltage Regulator Modules (VRM) - DDR termination supplies - Networking power supplies - Sequenced power supplies
Pin Assignment
(Top View) SS/SHDN VCC DRVH GND
1 8 COMP 2 AP2003 7 SENSE 3 6 BSTH 4 5 DRVL
Pin Descriptions
Name VCC DRVH DRVL Description Chip supply voltage High side driver output Low side driver output Bootstrap, high side driver Voltage sense input Compensation pin Soft start, a capacitor to ground sets the slow start time Ground
SOP-8L
Ordering Information
AP2003 X X X
BSTH SENSE COMP SS/ SHDN GND
Package Lead Free Packing S: SOP-8L Blank : Normal Blank : Tube L : Lead Free Package A : Taping
This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sale of the product.
Rev. 0.1 Feb.10, 2004 1/6
AP2003
Synchronous PWM Controller Block Diagram
VCC
(Preliminary)
Vbg
Under Voltage 0.8V + -
Oscillator
One-Shot
COMP Error Amp + Vcc 10uA SS/SHDN Foult 2uA GND 0.6V + DRVL DRVL 0.5V S + R Ob SENSE PWM DRVH BSTH DRVH Cross Current Control
Absolute Maximum Ratings
Symbol VIN JC JA TOP TST TLEAD Parameter VCC to GND Thermal Resistance Junction to Case Thermal Resistance Junction to Ambient Operating Temperature Range Storage Temperature Range Lead Temperature (Soldering) 10 Sec. Max. -1 to 14 60 160 -40 to +85 -65 to +150 300 Unit
o o
V C/W C/W
o o o
C C C
Anachip Corp. www.anachip.com.tw 2/6
Rev. 0.1 Feb.10, 2004
AP2003
Synchronous PWM Controller Electrical Characteristics
Symbol Power Supply VCC ICC VLINE Error Amplifier AOL IB Oscillator FOSC DCMAX Mofset Drivers IDRVH IDRVL Protection TDEAD Reference VREF Soft Start ISSC Charge Current VSS = 1.5V VSS = 1.5V 8.0 1.3 10 2 4.2 IO(REF) = 0.1mA TA = 25C 4.1 200 12 2.7 uA uA V V mV ISSD Discharge Current Under voltage lockout (UVLO) Upper threshold voltage VUT (VCC) Lower threshold voltage VLWT (VCC) VHT Hysteresis (VCC) Reference Voltage Accuracy 0oC to 70oC 0.792 -1 0.8 0.808 +1 V % Dead Time 45 100 nS DRVH Source/Sink DRVL Source/Sink VBSTH - VDRVH =4.5V VDRVH - VPHASE = 2V VBSTH - VDRVL = 4.5V VDRVL - VGND = 2V 1 1 A A Oscillator Frequency Oscillator Max Duty Cycle 180 90 200 95 220 KHz % Gain (AOL) Input Bias 50 5 8 dB uA Supply Voltage Supply Current Line Regulation VO = 2.5V VCC 4.2 6 0.5 16 10 V mA % Parameter
(Preliminary)
Unless specified: VCC = 12V; GND = 0V; FB = VO; VBSTH-GND = 12V; TJ = 25oC
Conditions
Min.
Typ.
Max.
Unit
Note 1. Specification refers to Typical Application Circuit. Note 2. This device is ESD sensitive. Use of standard ESD handling precautions is required.
Anachip Corp. www.anachip.com.tw 3/6
Rev. 0.1 Feb.10, 2004
AP2003
Synchronous PWM Controller Typical Application Circuit
(1)
+ C6 C7 C8 680/6.3V 680/6.3V 680/6.3V Vin 5V
(Preliminary)
1 2 C2 0.1u C5 10u 3 4
SS/SHDN VCC DRVH
COMP SENSE BSTH DRVL
8 7 6 5 R6 Option +12V R5 Option Q1 STP40NE Q2 STP40NE L1 4uH
R8 191* R7 127
GND
+ D1 Option C9 180/4V C10 180/4V C11 180/4V C12 180/4V C13 180/4V
AP2003
Vout=2.0V* -
Note: * Vout=0.8 x (1+R8/R7)
(2)
+ C6 C7 C8 680/6.3V 680/6.3V 680/6.3V Vin 5V
D2
1 2 C2 0.1u C5 10u 3 4
SS/SHDN VCC DRVH
COMP SENSE BSTH DRVL
8 7 6 R5 Option 5 R6 Option Q1 STP40NE Q2 STP40NE
C1 1u
R8 191* R7 127 L1 4uH +
GND
AP2003
5V input with Bootstrapped BSTH
D1 Option
C9 180/4V
C10 180/4V
C11 180/4V
C12 180/4V
C13 180/4V
Vout=2.0V* -
Note: * Vout=0.8 x (1+R8/R7)
Anachip Corp. www.anachip.com.tw 4/6
Rev. 0.1 Feb.10, 2004
AP2003
Synchronous PWM Controller Function Description
error amplifiers are clamped to a voltage proportional to the voltage on SS/ SHDN . This limits the on-time of the high-side MOSFETs, thus leading to a controlled ramp-up of the output voltages. Hiccup Mode During power up, the SS/ SHDN pin is internally pulled low until VCC reaches the under-voltage lockout level of 4.2V. Once VCC has reached 4.2V, the SS/ SHDN pin is released and begins to source 10uA of current to the external soft-start capacitor. As the soft-start voltage rises, the output of the internal error amplifier is clamped to this voltage. When the error signal reaches the level of the internal triangular oscillator, which swings from 1V to 2V at a fixed frequency of 200KHz, switching occurs. As the error signal crosses over the oscillator signal, the duty cycle of the PWM signal continues to increase until the output comes into regulation. The soft-start voltage will begin to decrease as the 2uA of current discharge the external capacitor. When the soft-start voltage reaches 0.8V, the SS/ SHDN pin will begin to source 10uA and begin to charge the external capacitor causing the soft-start voltage to rise again. Again, when the soft-start voltage reaches the level of the internal oscillator, switching will occur. In conclusion, above is shown a typical "12V Application Circuit" which has a BSTH voltage derived by bootstrapping input voltage to the PHASE node through diode D2. This circuit is very useful in cases where only single input power of 5V(or 12V) is available. In order to prevent substrate glitching, a small-signal diode should be placed in close proximity to the chip with cathode connected to PHASE and anode connected to GND.
(Preliminary)
Synchronous Buck Converter Primary VCORE power is provided by a synchronous, voltage-mode pulse width modulated (PWM) controller. This section has all the features required to build a high efficiency synchronous buck converter, shutdown function. The output voltage of the synchronous converter is set and controlled by the output of the error amplifier. The external resistive divider reference voltage is derived from an internal trimmed band-gap voltage reference. The inverting input of the error amplifier receives its voltage from the SENSE pin. The internal oscillator uses an on-chip capacitor and trimmed precision current sources to set the oscillation frequency to 200KHz. The triangular output of the oscillator sets the reference voltage at the inverting input of the comparator. When the oscillator output voltage drops below the error amplifier output voltage, the comparator output goes high. This pulls DRVL low, turning off the low-side FET, and DRVH is pulled high, turning on the high-side FET (once the cross-current control allows it). When the oscillator voltage rises back above the error amplifier output voltage, the comparator output goes low. This pulls DRVH low, turning off the high-side FET, and DRVL is pulled high, turning on the low-side FET (once the cross-current control allows it). As SENSE increases, the output voltage of the error amplifier decreases. This causes a reduction in the on-time of the high-side MOSFET connected to DRVH, hence lowering the output voltage. Under Voltage Lockout The under voltage lockout circuit of the AP2003 assures that the high-side MOSFET driver outputs remain in the off state whenever the supply voltage drops below set parameters. Lockout occurs if VCC falls below 4.1V. Normal operation resumes once VCC rises above 4.2V. Soft Start Initially, SS/ SHDN sources 10uA of current to charge an external capacitor. The outputs of the
Anachip Corp. www.anachip.com.tw 5/6
Rev. 0.1 Feb.10, 2004
AP2003
Synchronous PWM Controller Marking Information
(Top View)
8 5
(Preliminary)
Logo Part No.
AC AP2003 YY WW X X
1 4
ID code: internal Blank: normal L: Lead Free Package Xth week: 01~52 Year: "01" =2001 "02" =2002
~
SOP-8L
Package Information
Package Type: SOP-8L
E
H
L VIEW "A" D 7 (4X) A2 A 0.015x45
7 (4X)
A1
e
B y
C
VIEW "A"
Symbol A A1 A2 B C D E e H L y
Dimensions In Millimeters Min. Nom. Max. 1.40 1.60 1.75 0.10 0.25 1.30 1.45 1.50 0.33 0.41 0.51 0.19 0.20 0.25 4.80 5.05 5.30 3.70 3.90 4.10 1.27 5.79 5.99 6.20 0.38 0.71 1.27 0.10 8O 0O
Dimensions In Inches Min. Nom. Max. 0.055 0.063 0.069 0.040 0.100 0.051 0.057 0.059 0.013 0.016 0.020 0.0075 0.008 0.010 0.189 0.199 0.209 0.146 0.154 0.161 0.050 0.228 0.236 0.244 0.015 0.028 0.050 0.004 0O 8O
Anachip Corp. www.anachip.com.tw 6/6
Rev. 0.1 Feb.10, 2004

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