REI Datasheet
UC494A, UC494AC, UC495A, UC495AC
Advanced Regulatin Pulse Width Modulators
This entire series of PWM modulators each provide a complete pulse width modulation system in
a single monolithic integrated circuit. These devices include 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. These units are internally protected against
double-pulsing of a single output or from extraneous output signals when the input supply voltage
is below minimum.
Rochester Electronics
Manufactured Components
Rochester branded components are
manufactured using either die/wafers
purchased from the original suppliers
or Rochester wafers recreated from the
original IP. All recreations are done with
the approval of the OCM.
Parts are tested using original factory
test programs or Rochester developed
test solutions to guarantee product
meets or exceeds the OCM data sheet.
Quality Overview
• ISO-9001
• AS9120 certification
• Qualified Manufacturers List (QML) MIL-PRF-38535
•
Class Q Military
• Class V Space Level
• Qualified Suppliers List of Distributors (QSLD)
• Rochester is a critical supplier to DLA and
meets all industry and DLA standards.
Rochester Electronics, LLC is committed to supplying
products that satisfy customer expectations for
quality and are equal to those originally supplied by
industry manufacturers.
The original manufacturer’s datasheet accompanying this document reflects the performance
and specifications of the Rochester manufactured version of this device. Rochester Electronics
guarantees the performance of its semiconductor products to the original OEM specifications.
‘Typical’ values are for reference purposes only. Certain minimum or maximum ratings may be
based on product characterization, design, simulation, or sample testing.
© 2014 Rochester Electronics, LLC. All Rights Reserved 01272014
To learn more, please visit
www.rocelec.com
UC494A/AC
UC495A/AC
Advanced Regulating Pulse Width Modulators
FEATURES
•
•
•
•
•
•
•
•
•
•
Dual Uncommitted 40V, 200mA
Output Transistors
1% Accurate 5V Reference
Dual Error Amplifiers
Wide Range, Variable Deadtime
Single-ended or Push-pull
Operation
Under-voltage Lockout With
Hysteresis
Double Pulse Protection
Master or Slave Oscillator
Operation
UC495A: Internal 39V Zener Diode
UC495A: Buffered Steering Control
DESCRIPTION
This entire series of PWM modulators each provide a complete pulse width
modulation system in a single monolithic integrated circuit. These devices in-
clude 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. These units are internally protected against double-
pulsing of a single output or from extraneous output signals when the input
supply voltage is below minimum.
The UC495A contains an on-chip 39V zener diode for high-voltage applica-
tions where V
CC
would be greater than 40V, and a buffered output steering
control that overrides the internal control of the pulse steering flip-flop.
The UC494A is packaged in a 16-pin DIP, while the UC495A is packaged in
an 18 pin DIP. The UC494A, UC495A are specified for operation over the full
military temperature range of -55°C to +125°C, while the UC494AC,
UC495AC are designed for industrial applications from 0°C to +70°C.
BLOCK DIAGRAM
10/93
UC494A/AC
UC495A/AC
ABSOLUTE MAXIMUM RATINGS (Note
1, 2, 3)
Supply Voltage, V
CC
(Note 2). . . . . . . . . . . . . . . . . . . . . . . . 45V
Amplifier Input Voltages . . . . . . . . . . . . . . . . . . . . . . V
CC
+ 0.3V
Collector Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . 41V
Collector Output Current. . . . . . . . . . . . . . . . . . . . . . . . . 250mA
Continuous Total Dissipation . . . . . . . . . . . . . . . . . . . . 1000mW
@ (or below) 25°C free air temperature range (Note 3)
Storage Temperature Range . . . . . . . . . . . . . . . -65° to +150°C
Lead Temperature 1/16" (1.6mm) from case for 60 seconds,
J Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300°C
Lead Temperature 1/16" (1.6mm) from case for 10 seconds,
N Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C
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 Packaging Section of Databook regarding
thermal specifications and limitations of packages.
RECOMMENDED OPERATING CONDITIONS
Supply Voltage V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . 7V to 40V
Error Amplifier Input Voltages . . . . . . . . . . . . . -0.3V to V
CC
-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
. . . . . . . . . . . . . . . . . . . . . 1.8kΩ to 500kΩ
Oscillator Frequency . . . . . . . . . . . . . . . . . . . . 1kHz to 300kHz
Operating Free Air Temperature
UC494A, UC495A . . . . . . . . . . . . . . . . . . . . -55°C to +125°C
UC494AC, UC495AC . . . . . . . . . . . . . . . . . . . . 0°C to +70°C
CONNECTION DIAGRAMS
DIL-18 (TOP VIEW)
J or N Package
UC494A/AC
DIL-18 (TOP VIEW)
J or N Package
UC495A/AC
ELECTRICAL CHARACTERISTICS:
Unless otherwise stated, over recommended operating free-air temperature range,
V
CC
= 15V, f = 10kHz, T
A
= T
J.
PARAMETER
TEST CONDITIONS
Reference Section
Output Voltage V
REF
I
O
= 1mA, T
A
= 25°C
Input Regulation
V
CC
= 7V to 40V
Output Regulation
I
O
= 1mA to 10mA
Output Voltage Over Temperature
∆T
A
= Min. to Max.
Short Circuit Output Current
V
REF
= 0, T
A
= 25°C (Note 1)
Oscillator Section
Frequency (Note 2)
C
T
= 0.01µF, R
T
= 12kΩ
Standard Deviation Of Frequency (Note 3)
All Values of V
CC
, C
T
, R
T
, T
A
Constant
Frequency Change With Voltage
V
CC
= 7V to 40V, T
A
= 25°C
Frequency Change With Temperature
C
T
= 0.01µF, R
T
= 12kΩ,
∆T
A
= Min. to Max.
Deadtime Control Section
(Output Control Connected to V
REF
)
Input Bias Current (Pin 4)
V
(PIN 4)
= 0V to 5.25V
Maximum Duty-Cycle (Each Output)
V
(PIN 4)
= 0V
MIN
4.95
TYP
5
2
1
35
10
10
0.1
2
-2
45
-10
MAX UNITS
5.05
25
15
5.10
50
V
mV
mV
V
mA
kHz
%
%
%
µA
%
4.90
10
2
UC494A/AC
UC495A/AC
ELECTRICAL CHARACTERISTICS:
Unless otherwise stated, over recommended operating free-air temperature range,
V
CC
= 15V, f = 10kHz, T
A
= T
J.
PARAMETER
TEST CONDITION
Deadtime Control Section (cont.)
(Output Control Connected to V
REF
)
Input Threshold Voltage (Pin 4)
Zero Duty-Cycle
Maximum Duty-Cycle
Amplifier Section
Input Offset Voltage
V
O (PIN 3)
= 2.5V
Input Offset Current
V
O (PIN 3)
=2.5V
Input Bias Current
V
O (PIN 3)
= 2.5V
Common-Mode Input Voltage Range
V
CC
= 7V to 40V
Open Loop Voltage Gain
∆V
O
= 3V, V
O
= 0.5V to 3.5 V
Unity Gain Bandwidth
Common-Mode Rejection Ratio
V
CC
= 40V, T
A
= 25°C
Output Sink Current (Pin 3)
V
ID
= -15mV to -5V, V
(PIN 3)
= 0.7V
Output Source Current (Pin 3)
V
ID
= 15mV to 5V, V
(PIN 3)
= 3.5V
Output Section
Collector Off-State Current
V
CE
= 40V, V
CC
= 40V
Emitter Off-State Current
V
CC
= V
C
= 40V, V
E
= 0
Collector - Emitter Common-Emitter
V
E
= 0, I
C
= 200mA
Saturation Voltage Emitter-Follower
V
C
= 15V, I
E
= -200mA
Output Control Input Current
V
I
= V
REF
PWM Comparator Section
Input Threshold Voltage (Pin 3)
Zero Duty-Cycle
Input Sink Current (Pin 3)
V
(PIN 3)
= 0.7V
Steering Control
(UC495A, See Function Table)
Input Current
V
(PIN 13)
= 0.4V, Q
1 ACTIVE
V
(PIN 13)
= 2.4V, Q
2 ACTIVE
Deadband
Zener Diode Circuit
(UC495A)
Breakdown Voltage
V
CC
= 45V, I
Z
= 2mA
Sink Current
V
(PIN 15)
= 1V
Total Device
Standby Supply Current
Pin 6 at V
REF
, All other inputs and
outputs open
Under Voltage Lockout
Hysteresis
Switching Characteristics
(T
A
= 25°C)
Output Voltage Rise Time
Output Voltage Fall Time
Output Voltage Rise Time
Output Voltage Fall Time
MIN
TYP
3
0
2
25
-0.2
.03 to
V
CC
-2
70
65
0.3
-2
95
800
80
0.7
10
250
-1
MAX UNITS
3.3
V
V
mV
nA
µA
V
dB
kHz
dB
mA
mA
100
-100
1.3
2.5
3.5
4.5
µA
µA
V
V
mA
V
mA
µA
µA
mV
V
mA
mA
mA
V
mV
ns
ns
ns
ns
2
1.1
1.5
0.3
4
0.7
-200
300
500
36
0.2
V
CC
= 15V
V
CC
= 40V
3.5
300
39
0.3
6
9
45
0.6
10
15
6.5
Common-Emitter Configuration
R
L
= 68Ω, C
L
= 15pF
Emitter-Follower Configuration
R
L
= 68Ω, C
L
=15pF
100
25
100
40
200
100
200
100
Note 1: Duration of the short circuit should not exceed one second.
1.1
Note 2: Frequency for other values of C
T
and R
T i
s approximately
f
=
R
T
C
T
Note 3: Standard deviation is a measure of the statistical distribution about the mean as derived from the formula:
σ
=
√
n
2
Σ (
X
n
−
X
)
n
=
1
.
n
−
1
3
UC494A/AC
UC495A/AC
Figure 1. Slaving Two or More Control Circuits
Figure 2. Output Circuit of Error Amplifiers
Figure 3. Output Connections for Single-Ended and Push-Pull Configurations
Figure 4. Internal Buffer with Deadband for
Steering Control on UC495A
Figure 5. Operation with V
IN
> 40V Using Internal Zener
Figure 6. Error Amplifier Sensing Techniques
UNITRODE INTEGRATED CIRCUITS
7 CONTINENTAL BLVD.
•MERRIMACK,
NH 03054
TEL. (603) 424-2410
•
FAX (603) 424-3460
4
京公网安备 11010802033920号
EEWORLD
