ETC AZ3842AP

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Data Sheet
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
AZ3842/3/4/5
General Description
Features
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).
Applications
·
·
·
·
·
·
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.
SOIC-8
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
DIP-8
Off-line Converter
DC-DC Converter
Voltage Adapter
CRT Monitor Power Supply
Desktop Power Supply
DVD/STB Power Supply
SOIC-14
Figure 1. Package Types of AZ3842/3/4/5
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Data Sheet
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
AZ3842/3/4/5
Pin Configuration
M Package
(SOIC-14)
P/M Package
(DIP-8/SOIC-8)
COMP
1
14
VREF
COMP
1
8
VREF
N/C
2
13
N/C
VFB
2
7
VCC
VFB
3
12
VCC
ISENSE
3
6
OUTPUT
N/C
4
11
PWR VC
RT/CT
4
5
GND
ISENSE
5
10
OUTPUT
N/C
6
9
GND
RT/CT
7
8
PWR GND
Figure 2. Pin Configuration of AZ3842/3/4/5 (Top View)
Pin Description
Pin Number
8-pin
14-pin
Pin Name
1
1
COMP
2
3
VFB
The inverting input of the Error Amplifier. It is normally connected to the switching
power supply output through a resistor divider.
3
5
ISENSE
A voltage proportional to inductor current is connected to this input. The PWM uses
this information to terminate the output switch conduction.
4
7
RT/CT
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.
GND
The combined control circuitry and power ground.
5
Function
This pin is the Error Amplifier output and is made available for loop compensation.
6
10
OUTPUT
7
12
VCC
The positive supply of the control IC.
8
14
VREF
This is the reference output. It provides charging current for capacitor CT through
resistor RT.
8
PWR GND
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.
11
PWR VC
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.
9
GND
This pin is the control circuitry ground return and is connected back to the power
source ground.
2,4,6,13
N/C
No connection. These pins are not internally connected.
March 2003
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This output directly drives the gate of a power MOSFET. Peak currents up to 1.0 A
are sourced and sunk by this pin.
2
Rev: 1.0
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Data Sheet
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
AZ3842/3/4/5
Functional Block Diagram
VCC
7(12)
34V
GND
S/R
5(9)
5V
REF
OSC
T
COMP
ISENSE
VREF
6(10)
OUTPUT
(Note)
OVER TEMP
PROTECT
VFB
8(14)
INTERNAL
BIAS
VREF
GOOD
LOGIC
4(7)
VCC (PWR VC)
UVLO
2.50V
RT/CT
7(11)
ERROR
AMP
5(8)
S
2R
2(3)
R
1(1)
R
3(5)
GND
(PWR GND)
1V
CURRENT
SENSE
COMPARATOR
PWN
LATCH
Note: Toggle flip-flop used
for 3844/45 only
A(B)
A for 8-pin
B for 14-pin
Figure 3. Functional Block Diagram of AZ3842/3/4/5
Ordering Information
Package
Temperature Range
Part Number
Marking ID
Packing Type
SOIC-8
DIP-8
SOIC-14
-40oC~85oC
AZ3842/3/4/5M
AZ3842/3/4/5P
AZ3842/3/4/5MM
3842/3/4/5M
AZ3842/3/4/5P
AZ3842/3/4/5MM
Tape/Reel/Tube
Tube
Tape/Reel
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Data Sheet
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
AZ3842/3/4/5
Absolute Maximum Ratings (Note 1, 2)
Parameter
Symbol
Value
Unit
Supply Voltage
Vcc
30
V
Output Current
Io
土1
A
V(ANA)
-0.3 to 6.3
V
Error Amp Output Sink Current
ISINK(E.A)
10
mA
Power Dissipation at TA< 25 oC (DIP-8)
PD (Note 3)
1000
mW
Power Dissipation at TA<25 oC (SOIC-8)
PD (Note 3)
460
mW
Power Dissipation at TA<25 oC (SOIC-14)
PD (Note 3)
725
mW
TSTG
-65 ~+150
oC
TLEAD
+300
oC
Analog Inputs (8-pin: pin2,3, 14-pin: pin3,5)
Storage Temperature Range
Lead Temperature (Soldering, 10sec)
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
Ambient Temperature
March 2003
DataSheet 4 U .com
Symbol
Min
f
-40
TA
4
Max
Unit
500
KHz
85
o
C
Rev: 1.0
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Data Sheet
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
AZ3842/3/4/5
Electrical Characteristics
(VCC=15V, RT=10kΩ CT=3.3nF, TA= -40oC to +85oC, unless otherwise specified.)
Parameter
Symbol
Conditions
Min
Typ
Max
Unit
4.90
5.00
5.10
V
4
15
mV
4
15
mV
-100
-180
mA
0.2
0.4
mV/oC
µV
5
25
mV
52
57
KHz
0.2
1
%
REFERENCE SECTION
Reference Output Voltage
VREF
Line Regulation
∆VREF
TJ=25oC, IREF=1mA
12V ≤ VCC ≤25V
Load Regulation
∆VREF
1mA ≤ IREF ≤20mA
Short Circuit Output Current
ISC
TA=25oC
Temperature Stability
Output Noise Voltage
(Note 6)
Long Term Stability
TA=85oC,
50
1000 hours
OSCILLATOR SECTION
Oscillation Frequency
Frequency Change with Voltage
Oscillator Amplitude
f
∆f/f
VOSC
Temperature Stability
TJ=25oC
12V ≤ VCC ≤ 25V
47
Pin 4, peak to peak (Note 6)
1.7
V
(Note 6)
2.5
%
(Note 6)
-0.1
-2
µA
2.42
2.50
2.58
V
ERROR AMPLIFIER SECTION
Input Bias Current
Input Voltage
IBIAS
VI
Vpin 1=2.5V
Open Loop Voltage Gain
AVOL
2V ≤ VO ≤ 4V
65
90
dB
Power Supply Rejection Ratio
PSRR
12V ≤ VCC ≤ 25V
60
70
dB
Output Sink Current
ISINK
Vpin2=2.7V, Vpin1=1.1V
2
4
mA
-0.5
-0.8
mA
5
6
V
Output Source Current
ISOURCE
Vpin2=2.3V, Vpin1=5V
High Output Voltage
VOH
Vpin2=2.3V, RL=15kΩ to GND
Low Output Voltage
VOL
Vpin2=2.7V, RL=15kΩ to Pin 8
GV
(Note 4, 5)
Vpin1=5V(Note 4)
0.8
1.1
V
2.85
3
3.15
V/V
0.9
1
1.1
V
CURRENT SENSE SECTION
Gain
Maximum Input Signal
VI(MAX)
Power Supply Rejection Ratio
PSRR
Input Bias Current
IBIAS
Delay to Output
12V ≤ VCC ≤ 25V (Note 4, 6)
70
dB
-3
-10
µA
Vpin3 = 0 to 2V (Note 6)
150
300
ns
ISINK = 20mA
0.1
0.4
V
ISINK = 200mA
1.4
2.2
V
OUTPUT SECTION
Low Output Voltage
High Output Voltage
Rise Time
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DataSheet 4 U .com
VOL
VOH
tR
ISOURCE = 20mA
13
14
V
ISOURCE = 200mA
12
13
V
TJ=25oC, CL=1nF (Note 6)
5
50
150
ns
Rev: 1.0
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Data Sheet
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
AZ3842/3/4/5
Electrical Characteristics (Continued)
Parameter
Symbol
Fall Time
Conditions
tF
TJ=25oC, CL=1nF (Note 6)
UNDER -VOLTAGE LOCKOUT SECTION
Start Threshold
VTH(ST)
Min. Operation Voltage
(After Turn On)
Min
AZ3842/AZ3844
14.5
Typ
Max
Unit
50
150
ns
15.5
16.5
V
AZ3843/AZ3845
7.8
8.4
9.0
V
VOPR
(Min.)
AZ3842/AZ3844
8.5
10.0
11.5
V
AZ3843/AZ3845
7.0
7.6
8.2
V
D(Max.)
AZ3842/AZ3843
93
95
100
%
D(Max.)
AZ3844/AZ3845
46
48
50
%
0
%
0.6
1
mA
10
14
mA
PWM SECTION
Max. Duty Cycle
Min. Duty Cycle
D(Min.)
TOTAL STANDBY CURRENT SECTION
Start-Up Current
IST
ICC(OPR)
Operating Supply Current
Zener Voltage
Vpin3=Vpin2=0V
ICC=25mA
VZ
30
34
V
OVER-TEMPERATURE PROTECT SECTION
Shutdown Temperature
TSHUT
(Note 6)
165
oC
Temperature Hysteresis
THYS
(Note 6)
25
oC
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
A
COMP
1k
ERROR AMP
ADJUST
AZ3842
8
VREF
7
VCC
VCC
100k
VFB
2
0.1µf
5k
4.7k
1
ISENSE
ADJUST
ISENSE
RT/CT
3
6
OUTPUT
4
5
GND
CT
1K
1W
OUTPUT
0.1µf
GND
Figure 4. Basic Test Circuit
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Data Sheet
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
AZ3842/3/4/5
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
50K
n
=1
RT (Ω)
CT
CT
3
F
1
F
0n
=1
n
00
=1
10k
CT
Dead Time (µs)
10
F
5K
0.3
1
2.2
4.7
10
22
100
100
47
1k
10k
1M
Figure 6. Timing Resistor vs. Frequency
Figure 5. Oscillator Dead Time vs. Timing Capacitor
1.0
5.015
5.010
100k
Frequency (Hz)
Timing Capacitor (nF)
VCC=15V, IO=1mA
0.9
Start Up Current (mA)
Reference Voltage (V)
AZ3842
5.005
5.000
4.995
4.990
0.8
0.7
0.6
0.5
4.985
0.4
4.980
-40
-20
0
20
40
60
80
100
120
-40
o
Ambient Temperature ( C)
DataSheet 4 U .com
0
20
40
60
80
100
120
o
Ambient Temperature ( C)
Figure 7. Reference Voltage vs. Ambient Temperature
March 2003
-20
Figure 8. Start-up Current vs. Ambient Temperature
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Data Sheet
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
AZ3842/3/4/5
Typical Performance Characteristics (Continued)
16
4.0
15
3.5
o
VCC=15V
13
Saturation Voltage (V)
Supply Current (mA)
14
12
11
10
9
VCC=15V, TA=25 C
3.0
2.5
2.0
1.5
1.0
0.5
8
0.0
7
6
-40
-0.5
-20
0
20
40
60
80
100
120
o
Ambient Temperature ( C)
0
50
100
150
200
250
300
350
400
450
500
550
600
Output Sink Current (mA)
Figure 9. Supply Current vs. Ambient Temperature
Figure 10. Output Saturation Characteristics
90
80
o
Voltage Gain (dB)
70
VCC=15V, TA=25 C
60
50
40
30
20
10
0
10
100
1k
10k
100k
1M
Frequency (Hz)
Figure 11. Error Amplifier Open-loop Frequency Response
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Data Sheet
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
AZ3842/3/4/5
Typical Application
NTC
Bridge Diode
1N4007*4
C2
0.01µ
600V
+
R2
100k
J1
AC 220V
C1 50µ
C14
100µ/400V
R3
39k
2W
T
D3
8TQ100
L3
45µ
C9
2200µ
D1
Byv26e
R4 100
C10
1000µ
+
C11
1µ
C12
10µ
Z2
SA12A
+
+
D2
1N4148
7
R12
500
cc
VVCC
J2
12V/5A
C3
0.1µ
VREF 8
R5
1k
2
VFB
1
COMP
5
GND
C5
220p
RT/CT
4
OUTPUT
6
ISENSE
3
R14
130k
U1
AZ3842/3/4/5
R13
15k
R11
820
C6
2200p/600V
C4
10n
R8
39k/2W
R6
10
R7
1k
R15
100
Q1
IRF820
R16
8.2k
D4
Byv26e
U3
AZ431
C7
0.01µ
Z1
1N5819
C8
0.22µ
W1
1k
R10
0.51/1W
R9
7.5k
R18
3.9k
R17
2k
U2 PS521
Figure 12. Typical Application of AZ3842/3/4/5
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Data Sheet
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
AZ3842/3/4/5
Mechanical Dimensions
0.2±0.10
7°
0.70±0.025
4.9±0.10
7°
0.22±0.03
1.55±0.20
SOIC-8
0.32
8°
8°
D
6.00±0.20
0.90
1.00
3.90±0.10
φ0.8
0.20
D
20:1
±4°
4°
R0.15
R0.15
3°
±2°
0.42±0.09
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Data Sheet
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
AZ3842/3/4/5
Mechanical Dimensions (Continued)
SOIC-14
A
7°
0.38±0.10
×45°
8°
8°
+0.05
0.2-0.10
4°
±4°
0.70
7°
8° 3.90±0.10
1.55±0.20
0.42±0.09
9.5°
0.22±0.03
8.65±0.10
1.27
A
20:1
0.25 (0.20min)
R0.20
1.00
6.00±0.20
R0.20
0.55±0.05
0.25
1.30
±2°
3°
φ2.0
Depth 0.06～0.10
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Data Sheet
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
AZ3842/3/4/5
Mechanical Dimensions (Continued)
DIP-8
7.62±0.25
5°
9.2±0.10
6°
6°
4°
3.30±0.30
1.46±0.31
4°
0.7
φ3×0.15±0.05
0.254
0.457
0.28±0.07
2.54
10.0MAX
R0.75
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6.60±0.50
0.13MIN
12
Rev: 1.0
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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
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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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