CM494
A
DVANCED
R
EGULATING
P
ULSE
W
IDTH
M
ODULATOR
2000/12/29
Preliminary
Champion Microelectronic Corporation
Page 1
GENERAL DESCRIPTION
FEATURES
This of PWM modulator provides a complete pulse width
modulation system in a single monolithic integrated circuit.
This device includes a 5V reference accurate to
1%, two
independent amplifiers usable for both voltage and current
sensing, an externally synchronizable oscillator with its
linear ramp generator, and two-uncommitted transistor
output switches. These two outputs may be operated
either in parallel for single-ended operation or alternating
for push-pull applications with an externally controlled
dead-band. This unit is internally protected against
double-pulsing of a single output or from extraneous
output signals when the input supply voltage is below
minimum.
The CM494 contains an on-chip 39V zener diode for
high-voltage applications where Vcc would be greater
than 40V, and a buffered output steering control that
overrides the internal control of the pulse steering flip-flop.
!
Dual uncommitted 40V, 200mA output transistors.
!
1% accurate 5V reference.
!
Dual error amplifiers.
!
Wide range, variable dead time.
!
Single-ended or push-pull operation.
!
Under-voltage lockout with hysteresis.
!
Double pulse protection.
!
Master or slave oscillator operation.
APPLICATIONS
PIN CONFIGURATION
!
Linear Regulators
!
Adjustable Supplies
!
Switching Power Supplies
!
Battery Operated Computers
!
Instrumentation
!
Computer Disk Drives
16-PIN PDIP/SOP
(Top View)
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
1IN+
1IN-
FEEDBACK
DTC
CT
RT
GND
C1
2IN+
2IN-
REF
OUTPUT CTRL
VCC
C2
E2
E1
CM494
A
DVANCED
R
EGULATING
P
ULSE
W
IDTH
M
ODULATOR
2000/12/29
Preliminary
Champion Microelectronic Corporation
Page 2
BLOCK DIAGRAM
FUNCTION TABLE
Output Control
Connected to :
Output Function
Ground
V
REF
Single-Ended or
Parallel Operation
Push-Pull Alternating
Output
UM495A
Steering Control
Output Control at
V
REF
Output Function
Vs < 0.4V
Vs > 2.4V
PWM Output at Q1
PWM Output at Q2
ORDERING INFORMATION
Part Number
Temperature Range
Package
CM494CP 0
to 70
16-PIN DPIP (P16)
CM494CS 0
to 70
16-PIN SOP (S16)
+
_
+
_
2IN-
2IN+
1IN+
1IN-
1
2
16
15
Error Amplifier 2
Error Amplifier 1
Oscillator
6
5
CT
RT
_
+
_
+
0.1v
Pulse-Steering
Flip-Flop
Dead-Time Control
Comparator
PWM
Comparator
Reference
Regulator
VCC
REF
GND
7
4
DTC
3
FEEDBACK
OUTPUT CTRL
13
E1
C1
11
9
E2
C2
ID
C1
14
12
Q1 8
Q2
10
CM494
A
DVANCED
R
EGULATING
P
ULSE
W
IDTH
M
ODULATOR
2000/12/29
Preliminary
Champion Microelectronic Corporation
Page 3
ABSOULTE MAXIMUM RATINGS
Supply voltage, Vcc(Note 2).............................. 45V
Amplifier input voltages........................ Vcc + 0.3V
Collector output voltage................................. 41V
Collector output current.............................. 250mA
Continuous total dissipation........................ 1000mW
@ (or below) 25
free air temperature range (Note 3)
Storage temperature range..................-65
to + 150
Lead temperature 1 / 16"(1.6mm) from case for 60 seconds,
J package................................................300
Lead temperature 1 / 16"(1.6mm) from case for 10 seconds,
N package............................................. 260
Note 1: Over operating free air temperature range unless
otherwise noted.
Note 2: All voltage values are with respect to network
ground terminal 3.
Note 3: Consult package section of data book regarding
thermal specification and limitation of package.
RECOMMENDED OPERATING CONDITION
Supply voltage Vcc........................ 7V to 40V
Error amplifier input voltages.........-0.3 to Vcc-2V
Collector output voltage........................... .40V
Collector output current (each transistor)... 200mA
Current into feedback terminal....................0.3mA
Timing capacitor, C
T
... 0.47nF to 10,000nF
Timing resistor, R
T
....................1.8k
to 500k
Oscillator Frequency.....................1kHz to 300kHz
Operating free air temperature
UC494A, UC495A..................-55
to + 125
UC494AC, UC495AC...................0
to +70
CM494
A
DVANCED
R
EGULATING
P
ULSE
W
IDTH
M
ODULATOR
2000/12/29
Preliminary
Champion Microelectronic Corporation
Page 4
ELECTRICAL CHARACTERISTICS
: Unless otherwise stated, over recommended operating free-air
temperature range. Vcc = 15V, f = 10Khz, T
A
=T
J.
PARAMETER TEST
CONDITIONS
MIN
TYP
MAX
UNITS
Reference Section
Output voltage V
REF
lo = 1mA, T
A
= 25
4.75
5
5.25
V
Input regulation
Vcc = 7V to 40V
2
25
mV
Output regulation
lo = 1mA to 10mA
1
15
mV
Output voltage over temperature
T
A
= Min. to Max
4.90
5.10
V
Short circuit output current
V
REF
= 0, T
A
= 25
10
35
50
mA
Oscillator Section
Frequency (Note 2)
C
T
= 0.01F, R
T
= 12
10
kHz
Standard deviation of frequency (Note 3) All values of Vcc, C
T
, R
T
, T
A
10
%
Frequency change with voltage
Vcc = 7V to 40V, T
A
= 25
0.1
%
Frequency change with temperature
C
T
= 0.01F, R
T
= 12k
,
T
A
= Min. to Max
2
%
Deadtime Control Section (Output control connected to V
REF
)
Input bias current (Pin 4)
V (
PIN 4
) = 0V to 5.25V
-2
-10
A
Maximum duty-cycle (each output)
V (
PIN 4
) = 0V
45
%
Deadtime control Section (cont.)
Output control connected to V
REF
Zero duty-cycle
3
3.3
V
Input threshold voltage (Pin 4)
Maximum duty-cycle
0
V
Amplifier Section
Input offset voltage
Vo
(PIN 3)
= 2.5V
2
10
mV
Input offset current
Vo
(PIN 3)
= 2.5V
25
250
nA
Input bias current
Vo
(PIN 3)
= 2.5V
-0.2
-1
A
Common-mode input voltage range
Vcc = 7V to 40V
.03 to
Vcc -2
V
Open loop voltage gain
Vo = 3V, Vo = 0.5V to 3.5V
70
95
dB
Unity gain bandwidth
800
kHz
Common-mode rejection ratio
Vcc = 40V, T
A
= 25
65
80
dB
Output sink current (Pin 3)
V
ID
= -15mV to 5V, V
(Pin 3)
= 3.5V
0.3
0.7
mA
Output Source current (Pin 3)
V
ID
= -15mV to 5V, V
(Pin 3)
= 3.5V
-2
mA
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