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Advanced Analog Circuits
Data Sheet AZ494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS General Description
The AZ494 incorporates on a single chip all the functions required in the construction of a pulse-widthmodulation (PWM) control circuit. Designed primarily for power supply control, this device offers the flexibility to tailor the power supply control circuitry to a specific application. The AZ494 contains two error amplifiers, an on-chip adjustable oscillator, a dead-time control (DTC) comparator, a pulse-steering control flip-flop, a 5V regulator, and output control circuits. The error amplifiers exhibit a common-mode voltage range from -0.3V to VCC-2V. The dead-time control comparator has a fixed offset that provides approximately 5% dead time. The on-chip oscillator can be bypassed by terminating the RT pin to the reference output and providing a sawtooth input to the CT pin, or it can drive the common circuits in synchronous multiple-rail power supplies. The uncommitted output transistors can be configured in either common-emitter or emitter-follower output topology. The AZ494 provides for push-pull or singleended output operation, which can be selected through the output control function. The architecture of this device prohibits the possibility of either output being pulsed twice during push-pull operation. The AZ494 is characterized for operation from -40oC to 85oC.
Features
* * * * * * * Complete PWM power-control circuitry Uncommitted outputs for 200mA sink or source current Output control selects single-ended or push-pull operation Internal circuitry prohibits double pulse at either output Variable dead time provides control over total range Internal regulator provides a stable 5V reference supply with 5% tolerance Circuit architecture allows easy synchronization
Applications
* * SMPS Back Light Inverter
SOIC-16
DIP-16
Figure 1. Package Types of AZ494
March. 2003
1
Rev.1.0
Advanced Analog Circuits
Data Sheet AZ494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS Pin Configuration
M Package / P Package (SOIC-16 / DIP-16)
1IN + 1IN FEEDBACK DTC CT RT GND C1 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 2IN + 2IN REF OUTPUT CTRL VCC C2 E2 E1
Top View Figure 2. Pin Configuration of AZ494
Function Table
Input To Output Control VI = GND VI = Vref Output Function Single-ended or parallel output Normal push-pull operation
Functional Block Diagram
Output CTRL see Function Table RT CT 6 5 13 Oscillator Dead-Time Control Comparator DTC 4 0.12V Error Amplifier 1 1IN + 1IN 1 2 12 2IN + 2IN 16 15 0.7mA 3 Error Amplifier 2 Reference Regulator 14 7 V CC REF GND PWM Comparator D CK Q2 10 E2 Pulse-Steering Flip-Flop Q1 9 11 E1 C2 8 C1
FEEDBACK
Figure 3. Functional Block Diagram of AZ494
March. 2003
2
Rev.1.0
Advanced Analog Circuits
Data Sheet AZ494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS Ordering Information
Package SOIC-16 DIP-16 Temperature Range -40 C~85 C
o o
Part Number AZ494M AZ494P
Marking ID AZ494M AZ494P
Packing Type Tube Tube
Absolute Maximum Ratings (Note 1)
Parameter Supply Voltage (Note 2) Amplifier Input Voltage Collector Output Voltage Collector Output Current Package Thermal Impedance (Note 3) Lead Temperature 1.6mm from case for 10 seconds Storage Temperature Range ESD rating (Machine Model) TSTG Symbol VCC VI VO IO Value 40 -0.3 to VCC + 0.3 40 250 M Package P Package 260 -65 to 150 200 73 67
oC oC
Unit V V V mA
oC/W
JA
V
Note 1: Stresses greater than those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "Recommended Operation Ratings" is not implied. Exposure to "Absolute Maximum Ratings"for extended periods may affect device reliability. Note 2: All voltage values are with respect to the network ground terminal. Note 3: Maximum power dissipation is a function of TJ(max), JA and TA. The maximum allowable power dissipation at any allowable ambient temperature is PD = ( TJ(max) - TA ) / JA. Operating at the absolute maximum TJ of 150oC can affect reliability.
March. 2003
3
Rev.1.0
Advanced Analog Circuits
Data Sheet AZ494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS Recommended Operating Conditions
Parameter Supply Voltage Amplifier Input Voltage Collector Output Voltage Collector Output Current (Each Transistor) Current Into Feedback Terminal Oscillator Frequency Timing Capacitor Timing Resistor Operating Free-Air Temperature fosc CT RT TA 0.47 1.8 -40 Symbol VCC VI VO Min 7 -0.3 Max 36 VCC - 2 36 200 0.3 300 10000 500 85
Unit V V V mA mA KHz nF K
oC
March. 2003
4
Rev.1.0
Advanced Analog Circuits
Data Sheet AZ494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS Electrical Characteristics
All typical values, except for parameter changes with temperature, are at TA = 25oC. Vcc=15V, f=10KHz unless otherwise noted.
Parameter Reference Section Output Voltage (REF) Line Regulation Load Regulation Output Voltage Change with Temperature Short-Circuit Output Current (Note 5) ISC fosc All values of VCC, CT, RT and TA constant VCC=7V to 36V, TA = 25oC TA= MIN to MAX Vref IO=1mA VCC = 7V to 36V IO=1mA to 10mA TA = MIN to MAX REF = 0V 4.75 5 2 1 2 25 5.25 25 15 10 Symbol Conditions (Note 4) Min Typ Max
Unit V mV mV mV/V mA
Oscillator Section, CT = 0.01F, RT = 12K (See Figure 4) Frequency Standard Deviation of Frequency (Note 6) Frequency Change with Voltage Frequency Change with Temperature (Note 7) Error-Amplifier Section (See Figure 5) Input Offset Voltage Input Offset Current Input Bias Current Common-Mode Input Voltage Range Large-Signal Open-Loop Voltage Gain Large-Signal Unity-Gain Bandwidth Common-Mode Rejection Ratio Output Sink Current (FEEDBACK) Output Source Current (FEEDBACK) Output Section Collector Off-State Current Emitter Off-State Current Collector-Emitter Saturation Voltage Common Emitter Emitter Follower IC, OFF IE, OFF VCE = 36V, VCC=36V VCC = VC = 36V, VE = 0 VE = 0, IC =200mA VO (C1 or C2) = 15V, IE = -200mA 1.1 1.5 2 100 -100 1.3 2.5 A A V AVO GB CMRR ISINK ISOURCE VOS IOS IBIAS VO (FEEDBACK) = 2.5V VO (FEEDBACK) = 2.5V VO (FEEDBACK) = 2.5V VCC=7V to 36V VO = 3V, RL =2K, VO =0.5V to 3.5V VO =0.5V to 3.5V, RL =2K VO = 36V, TA = 25oC VID = -15mV to -5V, V(FEEDBACK) = 0.7V VID = 15mV to 5V, V(FEEDBACK) = 3.5V 65 0.3 -2 -0.3 to VCC-2 70 95 800 80 0.7 2 25 0.2 10 250 1 mV nA A V dB KHz dB mA mA 10 100 1 10 KHz Hz/KHz Hz/KHz Hz/KHz
March. 2003
5
Rev.1.0
Advanced Analog Circuits
Data Sheet AZ494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS Electrical Characteristics (Continued)
Parameter Output Control Input Current Dead-Time Control Section Input Bias Current Maximum Duty Cycle, Each Output Input Threshold Voltage PWM Comparator Section (See Figure 4) Input Threshold Voltage (FEEDBACK) Input Sink Current (FEEDBACK) Total Device Standby Supply Current ISTDBY RT=Vref, All other VCC = 15V inputs and outputs V = 36V CC open VI (DEAD-TIME-CTRL) =2V See Figure 4. tr tf tr tf Common-emitter Configuration See Figure 6 Emitter-follower Configuration See Figure 7 6 9 7.5 10 15 Zero duty cycle V(FEEDBACK) = 0.7V 0.3 4 0.7 4.5 VI = 0 to 5.25V VI (DEAD-TIME CTRL) = 0, CT =0.01F, RT =12K Zero Duty Cycle Maximum Duty Cycle 0 -2 45 3 3.3 -10 Symbol Conditions VI = Vref Min Typ Max 3.5
Unit mA A % V
V mA mA
Average Supply Current Switching Characteristics Rise Time Fall Time Rise Time Fall Time
mA
100 25 100 40
200 100 200 100
ns ns ns ns
Note 4: For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions. Note 5: Duration of the short circuit should not exceed one second. Note 6: Standard deviation is a measure of the statistical distribution about the mean as derived from the formula:
Note 7: Temperature coefficient of timing capacitor and timing resistor are not taken into account.
March. 2003
6
Rev.1.0
Advanced Analog Circuits
Data Sheet AZ494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS Parameter Measurement Information
VCC = 15V 12 4 Test Inputs 3 12K 6 5 0.01uF 1 2 16 15 13 50K VCC DTC FEEDBACK RT CT 1IN+ 1IN2IN+ 2INOUTPUT CTRL GND 7 REF 14 C1 E1 C2 E2 8 9 11 10 Output 2 150 2W 150 2W Output 1
Test Circuit
Voltage at C1 Voltage at C2 Voltage at CT
VCC 0V VCC 0V
Threshold Voltage DTC
0V Threshold Voltage
FEEDBACK 0.7V Duty Cycle 0% MAX
0%
Voltage Waveforms Figure 4. Operational Test Circuit and Waveforms
March. 2003
7
Rev.1.0
Advanced Analog Circuits
Data Sheet AZ494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS Parameter Measurement Information
Amplifier Under Test FEEDBACK
VI
Vref
Other Amplifier
Figure 5. Error Amplifier Characteristics
15V
68 2W Each Output Circuit Output CL = 15pF (See Note A) 90%
tf
tr 90%
10%
10%
Note A: CL includes probe and jig capacitance. Figure 6. Common-Emitter Configuration
15V Each Output Circuit
90%
90%
Output CL = 15pF (See Note A) 68 2W 10% tr 10% tf
Note A: CL includes probe and jig capacitance. Figure 7. Emitter-Follower Configuration
March. 2003
8
Rev.1.0
Advanced Analog Circuits
Data Sheet AZ494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS Typical Characteristics
100k
Vcc=15V o TA=25 C Oscillator Frequency-Hz
10k
0.001uF 0.01uF
1k
0.1uF
100
CT=1uF
10 1k
10k
100k
1M
Timing Resistance-
Figure 8. Oscillator Frequency vs. Timing Resistance
100 90 80
Vcc=15V
Vo=3V
TA=25 C
o
Voltage Gain-dB
70 60 50 40 30 20 10 0 1 10 100 1k 10k 100k 1M
Frequency-Hz
Figure 9. Error Amplifier Small-Signal Voltage Gain vs. Frequency
March. 2003
9
Rev.1.0
Advanced Analog Circuits
Data Sheet AZ494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS Mechanical Dimensions SOIC-16
1.65
1.00
1.30
0.70
7 7
0.406
B
A 20:1
0.550.05
0.25
2.0
Depth 0.06 0.10
1.27
10.00
2 3
R0.20 R0.20 0.25(0.20min)
6.04
0.200.05
C-C 50:1
3.94
0.203
8
9.5
B 20:1
S1.00x0.20
5 2 8
8
0.40x45
A
C
March. 2003
1.00
C
0.20
10
Rev.1.0
Advanced Analog Circuits
Data Sheet AZ494
PULSE-WIDTH-MODULATION CONTROL CIRCUITS Mechanical Dimensions (Continued) DIP-16
19.00.10 6 1.524 6
7.620.25 5
3.40.15
4
4
3x0.100.05
3.3
0.254 0.457 2.54
0.254 8.49.0
R0.75
March. 2003
6.30.10
0.7
11
Rev.1.0
Advanced Analog Circuits
http://www .aacmicro.com
USA: 1510 Montague Expressway, San Jose, CA 95131, USA China: 8th Floor, Zone B, 900 Yi Shan Road Shanghai 200233, China
Tel: 408-433 9888Fax: 408-432 9888 Tel: 86-21-6495 9539, Fax: 86-21-6485 9673
Taiwan: Room 2210, 22nd Fl, 333, Keelung Road, Secretary 1, Taipei, Taiwan Tel: 886-2-2564 3699, Fax: 886-2-2564 3770
IMPORTANT NOTICE Advanced Analog Circuits Corporation reserves the right to make changes to its products or specifications at any time, without notice, to improve design or performance and to supply the best possible product. Advanced Analog Circuits does not assume any responsibility for use of any circuitry described other than the circuitry embodied in Advanced Analog Circuits' products. The company makes no representation that circuitry described herein is free from patent infringement or other rights of Advanced Analog Circuits Corporation.

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