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Dual voltage-controlled oscillators



Qty Price (USD)
1-99 4.0
100-249 3.261
250-999 2.563
1,000+ 2.174

Quality information

RoHS Yes
Lead finish / Ball material NIPDAU
MSL rating / Peak reflow N/A for Pkg Type
Quality, reliability
& packaging information info-circle

Information included:

  • RoHS
  • Device marking
  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
  • Material content
  • Qualification summary
  • Ongoing reliability monitoring
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Export classification

  • US ECCN: EAR99

Packaging information

Package | Pins PDIP (N) | 16
Package qty | Carrier: 25 | TUBE
Operating temperature range (°C) 0 to 70
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Features for the SN74LS629

  • Separate Supply Voltage Pins for Isolation of Frequency Control Inputs and Oscillators from Output Circuitry
  • Highly Stable Operation over Specified Temperature and/or Supply Voltage Ranges


Description for the SN74LS629

These voltage-controlled oscillators (VCOs) are improved versions of the original VCO family: SN54LS124, SN54LS324 thru SN54LS327, SN74LS124, and SN74LS324 thru SN74LS327. These new devices feature improved voltage-to-frequency linearity, range, and compensation. With the exception of the 'LS624 and 'LS628, all of these devices feature two independent VCOs in a single monolithic chip. The 'LS624, 'LS625, 'LS626, and 'LS628 have complementary Z outputs. The output frequency for each VCO is established by a single external component (either a capacitor or crystal) in combination with voltage-sensitive inputs used for frequency control and frequency range. Each device has a voltage-sensitive input for frequency control; however, the 'LS624, 'LS628, and 'LS629 devices also have one for frequency range. (See Figures 1 thru 6).

The 'LS628 offers more precise temperature compensation than its 'LS624 counterpart. The 'LS624 features a 600 ohm internal timing resistor. The 'LS628 requires a timing resistor to be connected externally across Rext pins. Temperature compensation will be improved due to the temperature coefficient of the external resistor.

Figure 3 and Figure 6 contain the necessary information to choose the proper capacitor value to obtain the desired operating frequency.

A single 5-volt supply can be used: however, one set of supply voltage and ground pins (VCC and GND) is provided for the enable, synchronization-gating, and output sections, and a separate set (OSC VCC and OSC GND) is provided for the oscillator and associated frequency-control circuits so that effective isolation can be accomplished in the system. For operation of frequencies greater than 10 MHz, it is recommended that two independent supplies be used. Disabling either VCO of the 'LS625 and 'LS625 and 'LS627 can be achieved by removing the appropriate OSC VCC. An enable input is provided on the 'LS624, 'LS626, 'LS628, and 'LS629. When the enable input is low, the output is enabled: when the enable input is high, the internal oscillator is disabled, Y is high, and Z is low. Caution! Crosstalk may occur in the dual devices ('LS625, 'LS626, 'LS627 and 'LS629) when both VCOs are operated simultaneously. To minimize crosstalk, either of the following are recommended: (A) If frequencies are widely separated, use a 10-μh inductor between VCC pins. (B) If frequencies are closely spaced, use two separate VCC supplies or place two series diodes between the VCC pins.

The pulse-synchronization-gating section ensures that the first output pulse is neither clipped nor extended. The duty cycle of the square-wave output is fixed at approximately 50 percent.

The SN54LS624 thru SN54LS629 are characterized for operation over the full military temperature range of -55°C to 125°C. The SN74LS624 thru SN74LS629 are characterized for operation from 0°C to 70°C.




Qty Price (USD)
1-99 4.0
100-249 3.261
250-999 2.563
1,000+ 2.174

Carrier options

You can choose different carrier options based on the quantity of parts, including full reel, custom reel, cut tape, tube or tray.

custom reel is a continuous length of cut tape from one reel to maintain lot- and date-code traceability, built to the exact quantity requested. Following industry standards, a brass shim connects an 18-inch leader and trailer on both sides of the cut tape for direct feeding into automated assembly machines. TI includes a reeling fee for custom reel orders.

Cut tape is a length of tape cut from a reel. TI may fulfill orders using multiple strips of cut tapes or boxes to satisfy the quantity requested.

TI often ships  tube or tray  devices inside a box or in the tube or tray, depending on inventory availability. We pack all tapes, tubes or sample boxes according to internal electrostatic discharge and moisture-sensitivity-level protection requirements.

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Lot and date code selection may be available

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