Page 1
Semiconductor
PWM Control Circuit
The SL494 incorporates on a single monolithic chip all the
functions required in the construction of a pulse-width-modulation
control circuit. Designed primarily for power supply control, the SL494
contains an on-chip 5-volt regulator, two error amplifiers, adjustable
oscillator, dead-time control comparator, pulse-steering flip -flop, and
output-control circuitry. The uncommitted output transistors provide
either common-emitter or emitter-follower output capability. Push-pull
or single-ended output operation may be selected through the outputcontrol function. The architecture of the IL494 prohibits the possibility
of either output being pulsed twice during push-pull operation.
• Complete PWM Power Control Circuitry
• Uncommitted Outputs for 200 mA Sink or Source
• Output Control Selects Single-Ended or Push-Pull Operation
• Internal Circuitry Prohibits Double Pulse at Either Output
• Internal Regulator Provides a Stable 5 V Reference Supply
• Variable Dead-Time Provides Control Over Total Range
SL494
ORDERING INFORMATION
SL494N Plastic
SL494D SOIC
TA = -20°C to 85° C
for all packages
PIN ASSIGNMENT
FUNCTION TABLE
Output Control Output Function
Grounded Single-ended or Parallel Output
At V
Normal Push-Pull Oper ation
ref
LOGIC DIAGRAM
SLS
System Logic
Page 2
SL494
Semiconductor
MAXIMUM RATINGS
Symbol Parameter Value Unit
VCC Supply Voltage 41 V
VI Amplifier Input Voltage VCC +0.3 V
VO Collector Output Voltage 41 V
Collector Output Current 250 mA
Tstg Storage Temperature -65 to +150 °C
RECOMMENDED OPERATING CONDITIONS
Symbol Parameter Min Max Unit
VCC Supply Voltage 7 40 V
VI Amplifier Input Voltage -0.3 V
VO Collector Output Voltage 40 V
Collector Output Current (Each Transistor) 200 mA
Current Into Feed back Terminal 0.3 mA
CT Timing Capacitor 0.47 10.000 nF
RT Timing Resistor 1.8 500 KΩ
Oscillator Frequency 1 300 KHz
TA Operating Free-Air Temperature -20 +85 °C
- 2 V
CC
SLS
System Logic
Page 3
SL494
Semiconductor
ELECTRICAL CHARACTERISTICS (Temperature -20 ∼ 85°C, V
Symbol Parameter Test Conditions Min Max Unit
Reference Section
V
Output Voltage IO=1 mA 4.75 5.25 V
ref
V
Output regulation VCC=7 V to 40 V, TA=25°C 25 mV
regin
V
Input regulation IO=1 to 10 mA, TA=25°C 15 mV
regout
∆V
Output Voltage change with
ref
temperature
TA= -20°C to 85°C 1 %
= 15 V, f=10 kHz))
CC
ISC Short-circuit output current
Vref=0 50 mA
(Note 1)
Oscillator Section
f
Frequency CT=0.01 µF, RT=12 kΩ 6 14 KHz
OSC
δ f
Standard deviation of
OSC
frequency (Note 2)
δ f
Frequency change with
OSC(∆V)
voltage
δ f
Frequency change with
OSC(∆T)
temperature
All values of VCC, CT, RT, TA
Constant
VCC= 7 V to 40 V,
TA=25°C
CT=0.01 µF, RT=12 kΩ
TA= -20°C to 85°C
15 %
10 %
2 %
Dead Time Control Section
I
Input bias current (pin 4) VI= 0 to 5.25 V -10 µA
IB(2T)
DC
Maximum duty cycle, each
max
V
=0 V 45 %
I(pin 4)
output
V
Input threshold voltage Zero duty cycle 3.3 V
THD
(pin 4) Maximum duty cycle 0
Error Amp Section
VIO Input offset voltage V
IIO Input offset current V
IIB Input bias cur rent V
=2.5 V 10 mV
O(pin 3)
=2.5 V 250 nA
O(pin 3)
=2.5 V 1 µA
O(pin 3)
Common-mode input VCC= 7 V to 40 V LOW -0.3 V
voltage range HIGH VCC - 2
A
Open-loop voltage
vol
∆VO=3 V, VO=0.5 to 3.5 V 70 dB
amplification
fb Unity-gain bandwidth 100 kHz
CMRR Common-mode rejection ratio VCC=40 V, TA=25°C 65 dB
IO Output sink current (pin 3) VID=-15 mV to -5 V,
V
=0.7 V
O(pin 3)
IO+ Output source current
(pin 3)
System Logi c
SLS
VID=15 mV to 5 V,
V
=3.5 V
O(pin 3)
0.3 mA
-2 mA
Page 4
SL494
Semiconductor
ELECTRICAL CHARACTERISTICS(Temperature -20 ∼ 85°C, V
Symbol Parameter Test Conditions Min Max Unit
PWM Comparator Section
V
Input threshold voltage
THP
(pin 3)
Zero duty cycle 4.5 V
= 15 V, f=10 kHz))
CC
II Input sink current (pin 3) V
=0.7 V 0.3 mA
O(pin 3)
Switching Characteristics
trc Output voltage rise time Common-emitter configuration 200 ns
tfc Output voltage fall time Common-emitter configuration 100 ns
trf Output voltage rise time Emitter -follower configuration 200 ns
tff Output voltage fall time Emitter -follower configuration 100 ns
Output Section
I
Collector off-state current VCE=40 V, VCC=40 V 100 µA
C(off)
I
Emitter off-state current VCC=VC=40 V, VE=0 -100 µA
E(off)
V
Collector-
SAT
emitter
saturation
voltage
I
Output control input current VI=V
OCH
Commonemitter
Emitter follower
VE=0, IC=200 mA 1.3 V
VC=15 V, IE=-200 mA 2.5
3.5 mA
ref
Total Device
ICC Standby supply current All other inputs & VCC=15 V 10 mA
outputs open VCC=40 V 15
I
Average supply current V
CCA
=2 V 17 mA
(pin 4)
Notes: 1. Duration of the short circuit should not exceed one second.
2. Standard deviation is a measure of the statistical disribution about the mean as derived from the formula
N
σ =
∑ (x
n=1
- x)2
n
N - 1
SLS
System Logic
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