View AZ3842_684585.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

Advanced Analog Circuits
Data Sheet AZ3842/3/4/5 Features
* Robust VREF Line/Load Regulation Low Line Regulation : 4mV Low Load Regulation : 4mV High Stability of Reference Voltage over a Full Temperature Range: 0.2mV/ oC Operating Frequency up to 500KHz High PWM Frequency Stability over a Full Temperature Range: 2.5% High PWM Frequency Stability under a Full Supply Voltage Range: 0.2% Accurate Over-temperature Protection with Hysteresis UVLO with Hysteresis
CURRENT MODE PWM CONTROLLER General Description
The AZ3842/3/4/5 are high performance fixed frequency current-mode PWM controller series. These integrated circuits are optimized for off-line and DC-DC converter applications with minimum external components. They feature under-voltage lockout (UVLO) circuit for low start-up current, trimmed oscillator for precise duty cycle control, current sense comparator providing maximum current limiting and a totem pole output stage for increasing output current. In addition, these ICs also feature accurate protection against over-temperature, over-current and maximal output power. The AZ3842 and AZ3844 have UVLO thresholds of 15.5V(on) and 10V(off); The corresponding thresholds for AZ3843 and AZ3845 are 8.4 V(on) and 7.8V(off). The AZ3842 and AZ3843 can operate approaching 100% duty cycle; AZ3844 and AZ3845 can operate from zero to 50% duty cycle. These ICs are available in 3 packages: SOIC-8, DIP-8 and SOIC-14.
* * * * * *
Applications
* * * * * * Off-line Converter DC-DC Converter Voltage Adapter CRT Monitor Power Supply Desktop Power Supply DVD/STB Power Supply
SOIC-8
DIP-8
SOIC-14
Figure 1. Package Types of AZ3842/3/4/5
March 2003
1
Rev: 1.0
Advanced Analog Circuits
Data Sheet AZ3842/3/4/5
M Package (SOIC-14)
COMP 1 2 3 4 5 6 7 14 13 12 11 10 9 8 VREF N/C VCC PWR VC OUTPUT GND PWR GND
CURRENT MODE PWM CONTROLLER Pin Configuration
P/M Package (DIP-8/SOIC-8)
COMP VFB ISENSE RT/CT 1 2 3 4 8 7 6 5 VREF VCC OUTPUT GND N/C VFB N/C ISENSE N/C RT/CT
Figure 2. Pin Configuration of AZ3842/3/4/5 (Top View)
Pin Description
Pin Number 8-pin 1 2 3 4 14-pin 1 3 5 7 Pin Name COMP VFB ISENSE RT/CT Function This pin is the Error Amplifier output and is made available for loop compensation. The inverting input of the Error Amplifier. It is normally connected to the switching power supply output through a resistor divider. A voltage proportional to inductor current is connected to this input. The PWM uses this information to terminate the output switch conduction. The Oscillator frequency and maximum Output duty cycle are programmed by connecting resistor RT to VREF and capacitor CT to ground. Operation to 500 kHz is possible. The combined control circuitry and power ground. This output directly drives the gate of a power MOSFET. Peak currents up to 1.0 A are sourced and sunk by this pin. The positive supply of the control IC. This is the reference output. It provides charging current for capacitor CT through resistor RT. This pin is a separate power ground return that is connected back to the power source. It is used to reduce the effects of switching transient noise on the control circuitry. The Output high state (VOH) is set by the voltage applied to this pin. With a separate power source connection, it can reduce the effects of switching transient noise on the control circuitry. This pin is the control circuitry ground return and is connected back to the power source ground. No connection. These pins are not internally connected.
5 6 7 8 10 12 14 8 11
GND OUTPUT VCC VREF PWR GND PWR VC
9 2,4,6,13
GND N/C
March 2003
2
Rev: 1.0
Advanced Analog Circuits
Data Sheet AZ3842/3/4/5
CURRENT MODE PWM CONTROLLER Functional Block Diagram
VCC GND
7(12) 34V 5(9) UVLO S/R 5V REF
7(11)
VCC (PWR VC) VREF
8(14) INTERNAL BIAS
2.50V
VREF GOOD LOGIC
RT/CT
4(7)
OSC
T (Note)
6(10)
OUTPUT GND (PWR GND) A(B) A for 8-pin B for 14-pin
OVER TEMP PROTECT ERROR AMP 2(3) 1(1) 3(5) R 1V 2R
5(8) S R CURRENT SENSE COMPARATOR PWN LATCH Note: Toggle flip-flop used for 3844/45 only
VFB COMP ISENSE
Figure 3. Functional Block Diagram of AZ3842/3/4/5
Ordering Information
Package SOIC-8 DIP-8 SOIC-14 Temperature Range Part Number AZ3842/3/4/5M AZ3842/3/4/5P AZ3842/3/4/5MM Marking ID 3842/3/4/5M AZ3842/3/4/5P AZ3842/3/4/5MM Packing Type Tape/Reel/Tube Tube Tape/Reel
-40oC~85oC
March 2003
3
Rev: 1.0
Advanced Analog Circuits
Data Sheet AZ3842/3/4/5
CURRENT MODE PWM CONTROLLER Absolute Maximum Ratings (Note 1, 2)
Parameter Supply Voltage Output Current Analog Inputs (8-pin: pin2,3, 14-pin: pin3,5) Error Amp Output Sink Current Power Dissipation at TA< 25 oC (DIP-8) Power Dissipation at TA<25 oC (SOIC-8) Power Dissipation at TA<25 oC (SOIC-14) Storage Temperature Range Lead Temperature (Soldering, 10sec) Symbol Vcc Io V(ANA) ISINK(E.A) PD (Note 3) PD (Note 3) PD (Note 3) TSTG TLEAD
Value 30 1 -0.3 to 6.3 10 1000 460 725 -65 ~+150 +300
Unit V A V mA mW mW mW
oC oC
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 Operating Conditions" is not implied. Exposure to "Absolute Maximum Ratings" for extended periods may affect device reliability. Note 2: All voltages are with respect to pin 5 and all currents are positive into specified terminal. Note 3: Board thickness 1.6mm, board dimension 90mm x 90mm.
Recommended Operating Conditions
Parameter
Oscillation Frequency Symbol f TA
Min -40
Max 500 85
Unit KHz
o
Ambient Temperature
C
March 2003
4
Rev: 1.0
Advanced Analog Circuits
Data Sheet AZ3842/3/4/5
CURRENT MODE PWM CONTROLLER Electrical Characteristics
(VCC=15V, RT=10k CT=3.3nF, TA= -40oC to +85oC, unless otherwise specified.)
Parameter REFERENCE SECTION Reference Output Voltage Line Regulation Load Regulation Short Circuit Output Current Temperature Stability Output Noise Voltage Long Term Stability OSCILLATOR SECTION Oscillation Frequency Frequency Change with Voltage Oscillator Amplitude Temperature Stability ERROR AMPLIFIER SECTION Input Bias Current Input Voltage Open Loop Voltage Gain Power Supply Rejection Ratio Output Sink Current Output Source Current High Output Voltage Low Output Voltage CURRENT SENSE SECTION Gain Maximum Input Signal Power Supply Rejection Ratio Input Bias Current Delay to Output OUTPUT SECTION Low Output Voltage High Output Voltage Rise Time VOL VOH tR ISINK = 20mA ISINK = 200mA ISOURCE = 20mA ISOURCE = 200mA TJ=25oC, CL=1nF (Note 6) 13 12 GV VI(MAX) PSRR IBIAS Vpin3 = 0 to 2V (Note 6) (Note 4, 5) Vpin1=5V(Note 4) 12V VCC 25V (Note 4, 6) 2.85 0.9 IBIAS VI AVOL PSRR ISINK ISOURCE VOH VOL (Note 6) Vpin 1=2.5V 2V VO 4V 12V VCC 25V Vpin2=2.7V, Vpin1=1.1V Vpin2=2.3V, Vpin1=5V Vpin2=2.3V, RL=15k to GND Vpin2=2.7V, RL=15k to Pin 8 2.42 65 60 2 -0.5 5 f f/f VOSC TJ=25oC 12V VCC 25V Pin 4, peak to peak (Note 6) (Note 6) 47 (Note 6) TA=85oC, 1000 hours VREF VREF VREF ISC TJ=25oC, IREF=1mA 12V VCC 25V 1mA IREF 20mA TA=25oC 4.90 Symbol Conditions Min
Typ
Max
Unit
5.00 4 4 -100 0.2 50 5 52 0.2 1.7 2.5 -0.1 2.50 90 70 4 -0.8 6 0.8 3 1 70 -3 150 0.1 1.4 14 13 50
5.10 15 15 -180 0.4 25 57 1
V mV mV mA mV/oC V mV KHz % V %
-2 2.58
A V dB dB mA mA V
1.1 3.15 1.1 -10 300 0.4 2.2
V V/V V dB A ns V V V V
150
ns
March 2003
5
Rev: 1.0
Advanced Analog Circuits
Data Sheet AZ3842/3/4/5
CURRENT MODE PWM CONTROLLER Electrical Characteristics (Continued)
Parameter Fall Time Symbol tF Conditions TJ=25oC, CL=1nF (Note 6) AZ3842/AZ3844 AZ3843/AZ3845 AZ3842/AZ3844 AZ3843/AZ3845 AZ3842/AZ3843 AZ3844/AZ3845 14.5 7.8 8.5 7.0 93 46 Min
Typ 50 15.5 8.4 10.0 7.6 95 48
Max 150 16.5 9.0 11.5 8.2 100 50 0
Unit ns V V V V % % % mA mA V
oC oC
UNDER -VOLTAGE LOCKOUT SECTION Start Threshold VTH(ST) Min. Operation Voltage (After Turn On) PWM SECTION Max. Duty Cycle Min. Duty Cycle Start-Up Current Operating Supply Current Zener Voltage Shutdown Temperature Temperature Hysteresis D(Max.) D(Max.) D(Min.) IST ICC(OPR) VZ TSHUT THYS VOPR (Min.)
TOTAL STANDBY CURRENT SECTION 0.6 Vpin3=Vpin2=0V ICC=25mA (Note 6) (Note 6) 30 10 34 165 25 1 14
OVER-TEMPERATURE PROTECT SECTION
Note 4: Parameters are tested at trip point of latch with Vpin2 = 0. Note 5: Here gain is defined as: VPin 1 A= , 0 Vpin3 0.8V VPin 3 Note 6: These parameters, although guaranteed, are not 100% tested in production.
VREF 4.7k RT 2N2222 COMP 1k ERROR AMP ADJUST 4.7k 100k VFB 5k ISENSE ADJUST ISENSE RT/CT
2 7 1
A AZ3842
8
VCC
VREF VCC 0.1f OUTPUT GND 1K 1W OUTPUT 0.1f
3
6
4
5
CT
GND
Figure 4. Basic Test Circuit
March 2003
6
Rev: 1.0
Advanced Analog Circuits
Data Sheet AZ3842/3/4/5
CURRENT MODE PWM CONTROLLER Electrical Characteristics (Continued)
Figure 4 is the basic test circuit for AZ384x. In testing, the high peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and bypass capacitors should be connected close to pin 5 in a single point ground. The transistor and 5k potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to pin 3.
Typical Performance Characteristics
100k
30
10
50K
Dead Time (s)
CT
3
RT ()
n =1
CT 0n =1
F
CT
10k
F
n 00 =1
1
5K
F
0.3
1
2.2
4.7
10
22
47
100
100
1k
10k
100k
1M
Timing Capacitor (nF)
Frequency (Hz)
Figure 5. Oscillator Dead Time vs. Timing Capacitor
1.0
Figure 6. Timing Resistor vs. Frequency
5.015 5.010 5.005 5.000 4.995 4.990 4.985
VCC=15V, IO=1mA
0.9
AZ3842
Reference Voltage (V)
Start Up Current (mA)
-20 0 20 40 60 80
o
0.8
0.7
0.6
0.5
0.4
4.980 -40 100 120
-40
-20
0
20
40
60
o
80
100
120
Ambient Temperature ( C)
Ambient Temperature ( C)
Figure 7. Reference Voltage vs. Ambient Temperature
Figure 8. Start-up Current vs. Ambient Temperature
March 2003
7
Rev: 1.0
Advanced Analog Circuits
Data Sheet AZ3842/3/4/5
CURRENT MODE PWM CONTROLLER Typical Performance Characteristics (Continued)
16 15 14 4.0 3.5
Supply Current (mA)
13 12 11 10 9 8 7 6 -40
Saturation Voltage (V)
VCC=15V
3.0 2.5 2.0 1.5 1.0 0.5 0.0 -0.5
VCC=15V, TA=25 C
o
-20
0
20
40
60
o
80
100
120
0
50
100
150
200
250
300
350
400
450
500
550
600
Ambient Temperature ( C)
Output Sink Current (mA)
Figure 9. Supply Current vs. Ambient Temperature
Figure 10. Output Saturation Characteristics
90 80 70
VCC=15V, TA=25 C
o
Voltage Gain (dB)
60 50 40 30 20 10 0 10
100
1k
10k
100k
1M
Frequency (Hz)
Figure 11. Error Amplifier Open-loop Frequency Response
March 2003
8
Rev: 1.0
Advanced Analog Circuits
Data Sheet AZ3842/3/4/5
CURRENT MODE PWM CONTROLLER Typical Application
NTC
Bridge Diode 1N4007*4 C2 0.01 600V D1 Byv26e R3 39k 2W T
+ J1 AC 220V C1 50 + D2 1N4148 R2 100k C14 100/400V
D3 8TQ100
L3 45
C9 2200 +
C10 1000 +
C11 1
C12 10
Z2 SA12A
R4 100
J2 12V/5A
7 R12 500 2 C5 220p 1 R14 130k 5
Vcc VCC VFB COMP GND
VREF 8
R5 1k
C3 0.1 C4 10n C6 2200p/600V R8 39k/2W C8 0.22 R15 100 Q1 IRF820 D4 Byv26e U3 AZ431 R10 0.51/1W R17 2k U2 PS521 W1 1k R18 3.9k R16 8.2k
RT/CT OUTPUT ISENSE
4 R6 10 R7 1k C7 0.01
6
3
R13 15k R11 820
U1 AZ3842/3/4/5
Z1 1N5819
R9 7.5k
Figure 12. Typical Application of AZ3842/3/4/5
March 2003
9
Rev: 1.0
Advanced Analog Circuits
Data Sheet AZ3842/3/4/5
CURRENT MODE PWM CONTROLLER Mechanical Dimensions SOIC-8
1.550.20
0.220.03
0.32
8
4.90.10 7
0.700.025
0.20.10
7
8
D
6.000.20
D 20:1
0.8
3.900.10
4 4
0.90
1.00
R0.15
R0.15
0.420.09
3 2
March 2003
0.20
10
Rev: 1.0
Advanced Analog Circuits
Data Sheet AZ3842/3/4/5
CURRENT MODE PWM CONTROLLER Mechanical Dimensions (Continued) SOIC-14
7
+0.05 0.2-0.10
A
0.380.10 x45
8
8
0.70
7
8 3.900.10
4 4
1.550.20 0.420.09 1.27 A 20:1 0.25 (0.20min) 1.00 6.000.20 R0.20 R0.20
2 3
1.30
0.550.05
2.0 Depth 0.060.10
March 2003
0.25
0.220.03
Rev: 1.0
8.650.10
9.5
11
Advanced Analog Circuits
Data Sheet AZ3842/3/4/5
CURRENT MODE PWM CONTROLLER Mechanical Dimensions (Continued) DIP-8
9.20.10
6
6
7.620.25 5
3.300.30
1.460.31
0.7
4
4
3x0.150.05
0.254 0.457
2.54 0.13MIN
0.280.07 10.0MAX
R0.75
March 2003
6.600.50
12
Rev: 1.0
Advanced Analog Circuits
http://www.aacmicro.com
USA: 860 Hillview Court, Suite 160, Milpitas, CA 95035, USA China: 8th Floor, Zone B, 900 Yi Shan Road, Shanghai 200233, China
Tel: 408-586 8809, Fax: 408-586 8801 Tel: 86-21-6495 9539, Fax: 86-21-6485 9673
Taiwan: Room 2210, 22nd Fl, 333, Keelung Road, Sec. 1, Taipei 110, Taiwan Tel: 886-2-2758 6828, Fax: 886-2-2758 6892
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.

▲Up To Search▲

Price & Availability of AZ3842

	To Download AZ3842 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .