Data Sheet
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
General Description
The AZ494A/C is a voltage mode pulse width modula-
tion switching regulator control circuit designed prima-
rily for power supply control.
The AZ494A/C consists of a reference voltage circuit,
two error amplifiers, an on-chip adjustable oscillator, a
dead-time control (DTC) comparator, a pulse-steering
control flip-flop, and an output control circuit. The pre-
cision of voltage reference (V
REF
) is improved up to
±
1% through trimming and this provides a better output
voltage regulation. The AZ494A/C provides for push-
pull or single-ended output operation, which can be
selected through the output control.
The difference between AZ494A and AZ494C is that
they have 4.95V and 5V reference voltage respectively.
The AZ494A/C is available in standard packages of
DIP-16 and SOIC-16.
AZ494A/C
Features
·
·
·
·
·
·
Stable 4.95V/5V Reference Voltage Trimmed to
±1.0%
Accuracy
Uncommitted Output TR for 200mA Sink or
Source Current
Single-End or Push-Pull Operation Selected by
Output Control
Internal Circuitry Prohibits Double Pulse at Either
Output
Complete PWM Control Circuit with Variable
Duty Cycle
On-Chip Oscillator With Master or Slave Opera-
tion
Applications
·
·
·
SMPS
Back Light Inverter
Charger
SOIC-16
DIP-16
Figure 1. Package Types of AZ494A/C
Apr. 2006 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
1
Data Sheet
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
Pin Configuration
M/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
V
CC
C2
E2
E1
AZ494A/C
Figure 2. Pin Configuration of AZ494A/C (Top View)
Output Function Control Table
Signal for Output Control
V
I
= GND
V
I
= V
REF
Output Function
Single-ended or parallel output
Normal push-pull operation
Functional Block Diagram
OUTPUT CTRL
RT
CT
6
5
13
Oscillator
Dead-Time Control
Comparator
DTC
4
0.12V
Error Amplifier 1
1IN +
1IN -
1
2
12
Error Amplifier 2
2IN +
2IN -
16
15
0.7mA
3
+
Reference
Regulator
14
7
V
CC
REF
GND
+
+
PWM
Comparator
D
+
CK
Q2
10
E2
11
Pulse-Steering
Flip-Flop
Q1
9
E1
C2
8
C1
FEEDBACK
Figure 3. Functional Block Diagram of AZ494A/C
Apr. 2006 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
2
Data Sheet
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
Ordering Information
AZ494A/C
AZ494
-
E1: Lead Free
Circuit Type
Blank: Tin Lead
TR: Tape and Reel
Blank: Tube
Reference Voltage
A: 4.95V
C: 5.0V
Package
M: SOIC-16
P: DIP-16
Package
Temperature
Range
Part Number
Tin Lead
AZ494AM
Lead Free
AZ494AM-E1
AZ494AMTR-E1
AZ494CM-E1
AZ494CMTR-E1
AZ494AP-E1
AZ494CP-E1
Marking ID
Tin Lead
AZ494AM
AZ494AM
AZ494CM
AZ494CM
AZ494AP
AZ494CP
Lead Free
AZ494AM-E1
AZ494AM-E1
AZ494CM-E1
AZ494CM-E1
AZ494AP-E1
AZ494CP-E1
Packing Type
Tube
Tape & Reel
Tube
Tape & Reel
Tube
Tube
SOIC-16
-40 to 85
o
C
AZ494AMTR
AZ494CM
AZ494CMTR
AZ494AP
AZ494CP
DIP-16
BCD Semiconductor's Pb-free products, as designated with "E1" suffix in the part number, are RoHS compliant.
Apr. 2006 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
3
Data Sheet
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
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)
T
STG
Symbol
V
CC
V
I
V
O
I
O
Rθ
JA
M Package
P Package
260
-65 to 150
200
Value
40
-0.3 to V
CC
+ 0.3
40
250
73
67
o
C
o
C
AZ494A/C
Unit
V
V
V
mA
o
C/W
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 Operating Conditions" 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 T
J
(max), Rθ
JA
and T
A
. The maximum allowable power dissi-
pation at any allowable ambient temperature is P
D
= ( T
J
(max) - T
A
)/Rθ
JA
. Operating at the absolute maximum T
J
of 150
o
C can affect reliability.
Recommended Operating Conditions
Parameter
Supply Voltage
Collector Output Voltage
Collector Output Current
(Each Transistor)
Amplifier Input Voltage
Current Into Feedback Terminal
Reference Output Current
Timing Capacitor
Timing Resistor
Oscillator Frequency
PWM Input Voltage (Pin 3, 4, 14)
Operating Free-Air Temperature
T
A
Symbol
V
CC
V
C1
, V
C2
I
C1
, I
C2
V
I
I
FB
I
REF
C
T
R
T
f
osc
0.00047
1.8
1.0
0.3
-40
0.001
30
40
0.3
Min
7
Typ
15
30
Max
36
36
200
V
CC
- 2
0.3
10
10
500
200
5.3
85
Unit
V
V
mA
V
mA
mA
µF
KΩ
KHz
V
o
C
Apr. 2006 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
4
Data Sheet
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
Electrical Characteristics
T
A
= 25
o
C, V
CC
=20V, f=10KHz unless otherwise noted.
Parameter
Reference Section
Output Reference Voltage
for AZ494A
Output Reference Voltage
for AZ494C
Line Regulation
Load Regulation
Short-Circuit Output Current
Oscillator Section
C
T
=0.001µF, R
T
=30KΩ,
Oscillator Frequency
f
OSC
C
T
=0.01µF, R
T
=12KΩ
C
T
=0.01µF, R
T
=12KΩ, T
A
= -40
to 85
o
C
Frequency Change with Temperature
∆f
/∆T
C
T
=0.01µF, R
T
=12KΩ, T
A
= -40
to 85
o
C
Dead-Time Control Section
Input Bias Current
Maximum Duty Cycle,
Input Threshold Voltage
Error-Amplifier Section
Input Offset Voltage
Input Offset Current
Input Bias Current
Common-Mode Input Voltage Range
Open-Loop Voltage Gain
Unity-Gain Bandwidth
Common-Mode Rejection Ratio
Output Sink Current (Feedback)
Output Source Current (Feedback)
V
IO
I
IO
I
BIAS
V
CM
G
VO
BW
CMRR
I
SINK
I
SOURCE
V
ID
= -15mV to -5V,
V3 = 0.7V
V
ID
=15mV to 5V
V3 = 3.5V
65
-0.3
2
V3 = 2.5V
V3 = 2.5V
V3 = 2.5V
V
CC
=7V to 36V
V
O
=0.5V to 3.5V
-0.3
70
95
650
80
-0.7
2
25
0.2
10
250
1
V
CC
-2
mV
nA
µA
V
dB
KHz
dB
mA
mA
I
BIAS
D(MAX)
V
ITH
V
CC
=15V, V4= 0 to 5.25V
V
CC
=15V, V4= 0V,
Pin 13= V
REF
Zero Duty Cycle
Maximum Duty Cycle
0
45
3
3.3
-2
-10
µA
%
V
1
%
9.2
9.0
40
10
10.8
12
KHz
V
REF
I
REF
=1mA
I
REF
=1mA, T
A
= -40 to 85
o
C
V
REF
I
REF
=1mA
I
REF
=1mA, T
A
= -40 to 85
o
C
R
LINE
R
LOAD
I
SC
V
CC
= 7V to 36V
I
REF
=1mA to 10mA
V
REF
= 0V
10
4.90
4.85
4.95
4.9
4.95
4.95
5.0
5.0
2
1
35
5.0
5.05
5.05
5.1
25
15
50
V
V
V
V
mV
mV
mA
Symbol
Conditions
Min
Typ
Max
Unit
AZ494A/C
Apr. 2006 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
5
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