DS8615/DS8616 130/225 MHz Low Power Dual Modulus Prescalers General Description The DS8615 series products are low power dual modulus prescalers which divide by 32/33 and 40/41 respectively. The modulus control (MC) input selects division by N when at a high TTL level and division by N a 1 when at a low TTL level. The clock inputs are buffered, providing 40/100 mVrms input sensitivity. The two outputs provide the user the option to wire either a totem-pole or open-collector output structure. Additionally, the user can wire a resistor between the two output pins to minimize edge transition emissions. The outputs are designed to drive positive edge triggered PLLs. These products can be operated from either an unregulated 5.5V to 13.5V source or regulated 5V g 10% source. Unregulated operation is obtained by connecting VS to the source with VREG open. Regulated operation is obtained by connecting both VS and VREG to the supply source. The device can be used in phase-locked loop applications such as FM radio or other communications bands to prescale the input frequency down to a more usable level. A digital frequency display system can also be derived separately or in conjunction with a phase-locked loop, and it can extend the useful range of many inexpensive frequency counters to 225 MHz. Features Y Y Y Y Y Input frequency: 130 MHz (-4); 225 MHz (-2) Low power: 10 mA (-4, -2) Input sensitivity: 100 mVrms (-4); 40 mVrms (-2) Pin compatible with Motorola MC12015-16 prescalers Unregulated/regulated power supply option Logic and Connection Diagrams Generalized d N/N a 1 TL/F/5240 - 1 Dual-In-Line Package TL/F/5240 - 2 Top View Order Number DS8615N or DS8616N (-4, -2) See NS Package Number N08E C1995 National Semiconductor Corporation TL/F/5240 RRD-B30M105/Printed in U. S. A. DS8615/DS8616 130/225 MHz Low Power Dual Modulus Prescalers July 1992 Absolute Maximum Ratings (Note 1) Modulus Control Input Voltage If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. VS, Unregulated Supply Voltage VREG, Regulated Supply Voltage 7V Open-Collector Output Voltage 7V Operating Free Air Temperature Range 15V 7V Storage Temperature Range b 30 C to a 70 C b 65 C to a 150 C Recommended Operating Conditions Symbol Parameter DS8615-4 DS8616-4 Conditions Min Max DS8615-2 DS8616-2 Units Min Max VS Unregulated Supply Voltage VREG e Open 6.8 13.5 5.5 13.5 V VREG Regulated Supply Voltage VS and VREG Shorted 4.5 5.5 4.5 5.5 V fMAX Toggle Frequency VIN e 100 mVrms 20 130 VIN Input Signal Amplitude 100 300 VSLW Slew Rate 20 IOH High Level Output Current b 400 b 400 mA IOL Low Level Output Current 2.0 2.0 mA 40 225 MHz 300 mVrms 20 V/ms DC Electrical Characteristics (Notes 2 and 3) Symbol Parameter DS8615-4 DS8616-4 Conditions Min VIH High Level MC Input Voltage VS e 13.5V, VREG e Open VIL Low Level MC Input Voltage VREG e VS e 4.5V VOH High Level Output Voltage IOH e b0.4 mA, Pins 2 and 3 Shorted ICEX Open-Collector High Level Output Lower Output e 5.5V VOL Low Level Output Voltage VREG e 4.5V, IOL e 2 mA II Max MC Input Current VS e 13.5V, VREG e Open, VIH e 7V IIH High Level MC Input Current VREG e 4.5V, VIH e 2.7V IIL Low Level MC Input Current VS e 13.5V, VREG e Open, VIL e 0.4V IS Supply Current, Unregulated Mode IREG Supply Current, Regulated Mode DS8615-2 DS8616-2 Max 2.0 Min Units Max 2.0 0.8 VREG b2 V 0.8 VREG b2 V V 100 100 mA 0.5 0.5 V 100 100 mA 20 20 mA b 200 b 200 mA VS e 13.5V, VREG e Open 10 10 mA VS e VREG e 5.5V 10 10 mA Note 1: ``Absolute Maximum Ratings'' are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the device should be operated at these limits. The table of ``Electrical Characteristics'' provides conditions for actual device operation. Note 2: Unless otherwise specified Min/Max limits apply across the b 30 C to a 70 C range. Note 3: All current into device pins shown as positive, out of device pins as negative, all voltages referenced to ground unless otherwise noted. All values shown as Max or Min on absolute value basis. 2 AC Electrical Characteristics VCC e 5V g 10%, TA e b30 C to a 70 C Symbol Parameter Conditions Min tMODULUS Modulus Set-Up Time (Notes 4 and 5) RIN AC Input Resistance VIN e 100 MHz and 50 mVrms 1.0 Input Capacitance VIN e 100 MHz and 50 mVrms 3 CIN DS8615, DS8616 Max Units 65 ns kX 10 pF Note 1: ``Absolute Maximum Ratings'' are those values beyond which the safety of the device cannot be guaranteed. Except for ``Operating Temperature Range'' they are not meant to imply that the devices should be operated at these limits. The table of ``Electrical Characteristics'' provides conditions for actual device operation. Note 2: Unless otherwise specified min/max limits apply across the b 30 C to a 70 C temperature range. Note 3: All currents into device pins are shown as positive, out of device pins as negative, all voltages referenced to ground unless otherwise noted. All values shown as max or min on absolute value basis. Note 4: tMODULUS e the period of time the modulus control level must be defined prior to the positive transition of the prescaler output to ensure proper modulus selection. Note 5: See Timing Diagrams. Timing Diagram TL/F/5240 - 3 The logical state of the modulus control input just prior to the output's rising edge will determine the modulus ratio of the device immediately following that rising edge. The pulse width difference of N and N a 1 operation occurs during the output e HI conditions. Typical Applications TL/F/5240 - 4 TL/F/5240 - 5 Schematic Diagrams TL/F/5240 - 7 TL/F/5240 - 8 TL/F/5240-6 3 Application Hints the single ended mode, a capacitor of 0.001 mF (C2) should be connected between the unused input and the ground plane to provide a good high frequency bypass. The capacitor should be made larger for lower frequencies. The input waveform may be sinusoidal, but below about 20 MHz the operation of the circuit becomes dependent on the slew rate of the input rather than amplitude. A square wave input with a slew rate of greater than 20 V/ms will permit correct operation down to lower frequencies, provided the proper input coupling capacitor is provided. For regulated mode operation connect VS to VREG to ensure proper operation (see Typical Application diagram). OPERATING NOTES The signal source is usually capacitively coupled to the input. At higher frequencies a 0.001 mF input capacitor (C1) is usually sufficient, with larger values used at the lower frequencies. If the input signal is likely to be interrupted, it may be desirable to connect a 100 kX resistor between one input and ground to stabilize the device. In the single-ended mode, it is preferable to connect the resistor to the unused input. In the differential mode, the resistor can be connected to either input. The addition of the 100 kX pulldown resistor causes a loss of input sensitivity, but prevents circuit oscillations under no signal (open circuit) conditions. In addition, in 4 Physical Dimensions inches (millimeters) Molded Dual-In-Line Package (M) Order Number DS8614M-4, DS8615M-4, DS8616M-4 or DS8617M-4 NS Package Number M08A 5 DS8615/DS8616 130/225 MHz Low Power Dual Modulus Prescalers Physical Dimensions inches (millimeters) (Continued) Molded Dual-In-Line Package (N) Order Number DS8614N, DS8615N, DS8616N or DS8617N (-4, -3, -2) NS Package Number N08E LIFE SUPPORT POLICY NATIONAL'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 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