Revised March 2000 DM74LS503 8-Bit Successive Approximation Register (with Expansion Control) General Description Features The DM74LS503 register has an active LOW Enable (E) input that is used in cascading two or more packages for longer word lengths. A HIGH signal on E, after a START operation, forces Q7 HIGH and prevents the device from accepting serial data. With the E input of an DM74LS503 connected to the CC output of a preceding (more significant) device, the DM74LS503 will be inhibited until the preceding device is filled, causing its CC output to go LOW. This LOW signal then enables the DM74LS503 to accept the serial data on subsequent clocks. ■ Performs serial-to-parallel conversion ■ Expansion control for longer words ■ Storage and control for successive approximation A to D conversion ■ Low power Schottky version of 2503 Ordering Code: Order Number DM74LS503N Package Number N16E Package Description 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Connection Diagram Logic Symbol VCC = Pin 16 GND = Pin 8 Pin Descriptions Pin Names D Description Serial Data Input S Start Input (Active LOW) CP Clock Pulse Input (Active Rising Edge) E Conversion Enable Input (Active LOW) CC Conversion Complete Output (Active LOW) Q0–Q7 Parallel Register Outputs Q7 Complement of Q7 Output © 2000 Fairchild Semiconductor Corporation DS010190 www.fairchildsemi.com DM74LS503 8-Bit Successive Approximation Register March 1989 DM74LS503 Logic Diagrams Note: Cell logic is repeated for register stages Q5 to Q1. Connection for Longer Word Lengths www.fairchildsemi.com 2 Supply Voltage Note 1: The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The “Recommended Operating Conditions” table will define the conditions for actual device operation. 7V Input Voltage 7V 0°C to +70°C Operating Free Air Temperature Range −65°C to +150°C Storage Temperature Range Recommended Operating Conditions Symbol Parameter Min Nom Max 4.75 5 5.25 Units VCC Supply Voltage VIH HIGH Level Input Voltage V VIL LOW Level Input Voltage 0.8 V IOH HIGH Level Output Voltage −0.4 mA 8 mA 70 °C 2 IOL LOW Level Output Current TA Free Air Operating Temperature 0 tS (H) Setup Time HIGH or LOW 16 tS (L) S to CP 16 tH (H) Hold Time HIGH or LOW 0 tH (L) S to CP 0 tS (H) Setup Time HIGH or LOW 8 tS (L) D to CP 8 tH (H) Hold Time HIGH or LOW 10 tH (L) D to CP 10 tW (H) CP Pulse Width HIGH or LOW 46 tW (L) V ns ns ns ns ns 46 Electrical Characteristics Over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter Conditions VI Input Clamp Voltage VCC = Min, II = −18 mA VOH HIGH Level VCC = Min, IOH = Max, Output Voltage VIL = Max VOL II Min Typ (Note 2) Max Units −1.5 V 2.7 V LOW Level VCC = Min, IOL = Max, VIH = Min 0.5 Output Voltage IOL = 4 mA, VCC = Min 0.4 Input Current @ Max VCC = Max, VI = 7V Input Voltage VI = 10V V 0.1 mA IIH HIGH Level Input Current VCC = Max, VI = 2.7V 20 µA IIL LOW Level Input Current VCC = Max, VI = 0.4V −0.8 mA IOS Short Circuit Output Current VCC = Max (Note 3) ICC Supply Current VCC = Max −20 −100 mA 65 mA Note 2: All typicals are at VCC = 5V, TA = 25°C. Note 3: Not more than one output should be shorted at a time, and the duration should not exceed one second. Switching Characteristics VCC = +5.0V, TA = +25°C Symbol RL = 2 kΩ, CL = 15 pF Parameter Min Max fMAX Maximum Count Frequency tPLH Propagation Delay 15 35 MHz tPHL CP to Qn or CC 25 tPLH Propagation Delay 20 tPHL E to Q7 24 3 Units ns ns www.fairchildsemi.com DM74LS503 Absolute Maximum Ratings(Note 1) DM74LS503 8-Bit Successive Approximation Register Physical Dimensions inches (millimeters) unless otherwise noted 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Package Number N16E Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications. LIFE SUPPORT POLICY FAIRCHILD’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 FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. 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 (c) 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. www.fairchildsemi.com www.fairchildsemi.com 4