BETAPIN 1 · Error amplifier inputs
Error amplifier 1 noninverting input1IN+
Function
A higher voltage than 1IN− demands shorter output pulses.
How to connect
Ground in the open-loop pulse example.
Dual-output PWM controller
TL494 Pinout
Explore TL494 pins, signal names, electrical functions and connection guidance for each package.
Package view
16Physical pins
TL494CNPDIP-16
Manufacturer-referencedTexas Instruments
Pin diagram
Select a pin to explore its connection
Highlight
TL494CNPDIP-16Top view
TL494CDRSOIC-16Top view
Click a lead or use the arrow keys. Top view
PIN 2 · Error amplifier inputs
Error amplifier 1 inverting input1IN−
Function
Reference input for the first error amplifier.
How to connect
Connect to REF14 in the open-loop example.
PIN 3 · PWM and mode control
PWM feedback nodeFEEDBACK
Function
Shared error-amplifier output and PWM control node; increasing it suppresses pulses.
How to connect
Leave externally unconnected in this DTC-controlled demonstration.
Electrical note
Do not short this node to ground while an amplifier is trying to drive it HIGH.
PIN 4 · PWM and mode control
Dead-time controlDTC
Function
Increasing this input shortens the conduction interval independently of the error amplifiers.
How to connect
Connect to the wiper of a 10 kΩ potentiometer between REF14 and GND.
Electrical note
Start with the wiper near REF for outputs OFF, then reduce it slowly.
PIN 5 · Oscillator network
Oscillator capacitorCT
Function
Charges and discharges to form the internal timing ramp.
How to connect
Connect 1 nF to GND; keep the loop short.
PIN 6 · Oscillator network
Oscillator resistorRT
Function
Sets the timing capacitor charging current.
How to connect
Connect 100 kΩ to GND.
PIN 7 · Ground
Common returnGND
Function
Reference for control, oscillator and supply.
How to connect
Join bypass, timing and scope returns.
PIN 8 · Uncommitted outputs
Output transistor 1 upper contactC1
Function
Uncommitted output contact; the example uses it as a pulled-up switching output.
How to connect
Connect 4.7 kΩ to +12 V and a high-impedance scope channel.
Electrical note
Output goes LOW when its transistor conducts.
PIN 9 · Uncommitted outputs
Output transistor 1 lower contactE1
Function
Return-side contact of output transistor 1.
How to connect
Ground in this sinking-output example.
PIN 10 · Uncommitted outputs
Output transistor 2 lower contactE2
Function
Return-side contact of output transistor 2.
How to connect
Ground in this sinking-output example.
PIN 11 · Uncommitted outputs
Output transistor 2 upper contactC2
Function
Second uncommitted output contact.
How to connect
Connect its own 4.7 kΩ to +12 V and the second scope channel.
PIN 12 · Supply
Control supplyVCC
Function
Supplies the controller and reference regulator.
How to connect
Apply +12 V with 100 nF and local bulk decoupling to GND.
PIN 13 · PWM and mode control
Output mode selectionOUTPUT CTRL
Function
LOW selects simultaneous single-ended operation; REF selects alternating push-pull operation.
How to connect
Tie to GND in the main example. Change modes only with power removed.
Electrical note
This mode pin is not intended as a PWM switching input.
PIN 14 · Bias reference
Five-volt reference outputREF
Function
Regulated reference for bias and control networks.
How to connect
Bypass with 100 nF; connect the control potentiometer and amplifier inverting inputs.
Electrical note
Reference current is limited; it does not supply motors or power loads.
PIN 15 · Error amplifier inputs
Error amplifier 2 inverting input2IN−
Function
Reference input for the second amplifier.
How to connect
Connect to REF14 in the open-loop example.
PIN 16 · Error amplifier inputs
Error amplifier 2 noninverting input2IN+
Function
A higher voltage than 2IN− demands shorter pulses.
How to connect
Ground in the open-loop example.