Product details

Technology Family LS Bits (#) 2 Supply voltage (Min) (V) 4.75 Supply voltage (Max) (V) 5.25 Input type Bipolar Output type Push-Pull ICC (Max) (uA) 55000 IOL (Max) (mA) 24 IOH (Max) (mA) -1.2
Technology Family LS Bits (#) 2 Supply voltage (Min) (V) 4.75 Supply voltage (Max) (V) 5.25 Input type Bipolar Output type Push-Pull ICC (Max) (uA) 55000 IOL (Max) (mA) 24 IOH (Max) (mA) -1.2
PDIP (N) 16 181 mm² 19.3 x 9.4 SOIC (D) 16 59 mm² 9.9 x 6
  • 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

 

  • 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

 

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.

 

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.

 

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Technical documentation

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Type Title Date
* Data sheet Voltage-Controlled Oscillators datasheet 01 Mar 1988
Selection guide Logic Guide (Rev. AB) 12 Jun 2017
Application note Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) 02 Dec 2015
User guide LOGIC Pocket Data Book (Rev. B) 16 Jan 2007
Application note Semiconductor Packing Material Electrostatic Discharge (ESD) Protection 08 Jul 2004
More literature Logic Cross-Reference (Rev. A) 07 Oct 2003
Application note TI IBIS File Creation, Validation, and Distribution Processes 29 Aug 2002
Application note Designing With Logic (Rev. C) 01 Jun 1997
Application note Designing with the SN54/74LS123 (Rev. A) 01 Mar 1997
Application note Input and Output Characteristics of Digital Integrated Circuits 01 Oct 1996
Application note Live Insertion 01 Oct 1996

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Evaluation board

14-24-LOGIC-EVM — Generic Logic EVM Supporting 14 through 24 Pin PW, DB, D, DW, NS, DYY, and DGV Packages

This EVM is designed to support any logic device that has a D, DW, DB, NS, PW, DYY or DGV package in a 14 to 24 pin count.

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PDIP (N) 16 View options
SOIC (D) 16 View options

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