ETC UC495ACJ

UC494A/AC
UC495A/AC
Advanced Regulating Pulse Width Modulators
FEATURES
DESCRIPTION
•
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
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 singleended operation or alternating for push-pull applications with an externally
controlled dead-band. These units are internally protected against doublepulsing of a single output or from extraneous output signals when the input
supply voltage is below minimum.
•
Double Pulse Protection
•
Master or Slave Oscillator
Operation
•
UC495A: Internal 39V Zener Diode
•
UC495A: Buffered Steering Control
The UC495A 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.
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
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UC494A/AC
UC495A/AC
ABSOLUTE MAXIMUM RATINGS (Note 1, 2, 3)
RECOMMENDED OPERATING CONDITIONS
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°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.
Supply Voltage VCC . . . . . . . . . . . . . . . . . . . . . . . . . . 7V to 40V
Error Amplifier Input Voltages . . . . . . . . . . . . . -0.3V to VCC-2V
Collector Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V
Collector Output Current (each transistor) . . . . . . . . . . . 200mA
Current into Feedback Terminal. . . . . . . . . . . . . . . . . . . . 0.3mA
Timing Capacitor, CT . . . . . . . . . . . . . . . . . 0.47nF to 10,000nF
Timing Resistor, RT . . . . . . . . . . . . . . . . . . . . . 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,
VCC = 15V, f = 10kHz, TA = TJ.
PARAMETER
TEST CONDITIONS
Reference Section
Output Voltage VREF
IO = 1mA, TA = 25°C
Input Regulation
VCC = 7V to 40V
Output Regulation
IO = 1mA to 10mA
Output Voltage Over Temperature
∆TA = Min. to Max.
Short Circuit Output Current
VREF = 0, TA = 25°C (Note 1)
Oscillator Section
Frequency (Note 2)
CT = 0.01µF, RT = 12kΩ
Standard Deviation Of Frequency (Note 3)
All Values of VCC, CT, RT, TA Constant
Frequency Change With Voltage
VCC = 7V to 40V, TA = 25°C
Frequency Change With Temperature
CT = 0.01µF, RT = 12kΩ, ∆TA = Min. to Max.
Deadtime Control Section (Output Control Connected to VREF)
Input Bias Current (Pin 4)
V(PIN 4) = 0V to 5.25V
Maximum Duty-Cycle (Each Output)
V(PIN 4) = 0V
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2
MIN
TYP
4.95
5
2
1
4.90
10
35
MAX UNITS
5.05
25
15
5.10
50
V
mV
mV
V
mA
2
kHz
%
%
%
10
10
0.1
-2
45
-10
µA
%
UC494A/AC
UC495A/AC
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, over recommended operating free-air temperature range,
VCC = 15V, f = 10kHz, TA = TJ.
PARAMETER
TEST CONDITION
Deadtime Control Section (cont.) (Output Control Connected to VREF)
Input Threshold Voltage (Pin 4)
Zero Duty-Cycle
Maximum Duty-Cycle
Amplifier Section
Input Offset Voltage
VO (PIN 3) = 2.5V
Input Offset Current
VO (PIN 3) =2.5V
Input Bias Current
VO (PIN 3) = 2.5V
Common-Mode Input Voltage Range
VCC = 7V to 40V
Open Loop Voltage Gain
∆VO = 3V, VO = 0.5V to 3.5 V
Unity Gain Bandwidth
Common-Mode Rejection Ratio
VCC = 40V, TA = 25°C
Output Sink Current (Pin 3)
VID = -15mV to -5V, V(PIN 3) = 0.7V
Output Source Current (Pin 3)
VID = 15mV to 5V, V(PIN 3) = 3.5V
Output Section
Collector Off-State Current
VCE = 40V, VCC = 40V
Emitter Off-State Current
VCC = VC = 40V, VE = 0
Collector - Emitter Common-Emitter
VE = 0, IC = 200mA
Saturation Voltage Emitter-Follower
VC = 15V, IE = -200mA
Output Control Input Current
VI = VREF
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, Q1 ACTIVE
V(PIN 13) = 2.4V, Q2 ACTIVE
Deadband
Zener Diode Circuit (UC495A)
Breakdown Voltage
VCC = 45V, IZ = 2mA
Sink Current
V(PIN 15) = 1V
Total Device
Standby Supply Current
Pin 6 at VREF, All other inputs and
outputs open
Under Voltage Lockout
Hysteresis
Switching Characteristics (TA = 25°C)
Output Voltage Rise Time
Output Voltage Fall Time
Output Voltage Rise Time
Output Voltage Fall Time
MIN
3.3
V
V
2
25
-0.2
10
250
-1
mV
nA
µA
V
0
.03 to
VCC -2
70
65
0.3
-2
95
800
80
0.7
µA
µA
V
V
mA
4.5
V
mA
-200
300
µA
µA
mV
39
0.3
45
0.6
V
mA
6
9
10
15
6.5
mA
mA
V
mV
200
100
200
100
ns
ns
ns
ns
1.1
1.5
0.3
dB
kHz
dB
mA
mA
100
-100
1.3
2.5
3.5
2
4
0.7
500
36
0.2
VCC = 15V
VCC = 40V
300
Common-Emitter Configuration
RL = 68Ω, CL = 15pF
Emitter-Follower Configuration
RL = 68Ω, CL=15pF
RTCT
Note 3: Standard deviation is a measure of the statistical distribution about the mean as derived from the formula:

√
MAX UNITS
3
3.5
Note 1: Duration of the short circuit should not exceed one second.
1.1
Note 2: Frequency for other values of CT and RT is approximately f =
σ=
TYP
n
2
Σ (Xn − X)
n=1
.
n−1
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3
100
25
100
40
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 VIN > 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
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4
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