CDP1857C_1 INTERSIL | Alldatasheet
Document overview
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Technical content
Features
- Provides Easy Connection of I/O to CDP1800-Series Microprocessor Data Bus
- Non-Inverting Fully Buffered Data Transfer
Description
The CDP1857C is a 4-bit CMOS non-inverting bus separator designed for use in CDP1800-series microprocessor systems. It can be controlled directly by a 1800-series microprocessor without the use of additional components. The CDP1857 is designed for use as a bus buffer or separator between the 1800-series microprocessor data bus and I/O devices. It provides a chip-select (CS) input signal which, when high (1), enables the bus-separator three-state output drivers. The direction of data flow, when enabled, is controlled by the MRD input signal. In the CDP1857, when MRD = 1, it enables the three-state bus driv- ers (DB0-DB3) and transfers data from the DATA-IN lines onto the data bus. When MRD = 0, it disables the three-state bus drivers (DB0-DB3) and enables the three-state data output drivers (DO0- DO3), thus, transferring data from the data bus to the DATA-OUT ter- minals. The CDP1857 can be used as a bidirectional bus buffer by connect- ing the corresponding DI and DO terminals (Figure 1). The MRD out- put signal from the 1800-series microprocessor has the correct polarity to control the CDP1857 when it is used as I/O bus buffer/sep- arator. Therefore, the 1800-series microprocessor MRD signal can be connected directly to the MRD input of CDP1857. See Function Table 1 for use of the CDP1857 as an I/O bus buffer/separator. The CDP1857C is supplied in 16-lead hermetic, dual-in-line ceramic packages (D suffix), and in 16-lead plastic packages (E suffix). Pinout
16 LEAD DIP
Ordering Information
NUMBER TEMP. RANGE PACKAGE PKG. NO. CDP1857CE -40 oC to +85oCP D I P E 1 6 . 3 CDP1857CD -40 oC to +85oCS B D I P D 1 6 . 3 TABLE 1. CDP1857 FUNCTION FOR I/O BUS SEPARATOR
0 X High Impedance High Impedance
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a trademark of Intersil Americas Inc.
Functional Diagram For CDP1857 DB0 CS DI0 DO0 DI1 DO1 DI2 DO2 DI3 DO3 16 = VDD 8 = VSS MRD DB1 DB2 DB3 File Number
Absolute Maximum Ratings Thermal Information DC Supply Voltage Range, (VDD) Thermal Resistance (Typical) θJA (oC/W) θJC (oC/W) Device Dissipation Per Output Transistor TA = Full Package Temperature Range Operating Temperature Range (TA) At distance 1/16 ± 1/32 In. (1.59 ± 0.79mm) from case for 10s max CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress o nly rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not i mplied. Static Electrical Specifications At TA = -40oC to +85oC, Except as Noted: PARAMETER SYMBOL CONDITIONS MIN (NOTE 1) TYP MAX UNITS VO (V) VIN (V) VDD (V) Quiescent Device Current I DD -0 , 5 5 - 5 5 0 µA Output Low Drive (Sink) Current I OL 0 . 40 , 55 1 . 6 3 . 2 - m A Output High Drive (Source) Current I OH 4 . 60 , 55 - 1 . 1 5 - 2 . 3- m A Output Voltage Low-Level (Note 3) V OL -0 , 5 5 - 0 0 . 1 V Output Voltage High-Level (Note 3) V OH -0 , 5 5 4 . 9 5 -V Input Low Voltage V IL 0.5, 4.5 - 5 - - 1.5 V Input High Voltage V IH 0.5, 4.5 - 5 3.5 - - V Input Leakage Current I IN Any Input 0, 5 5 - - ±1 µA Operating Current (Note 2) I DD1 0, 5 0, 5 5 - 50 100 µA Input Capacitance C IN - ---5 7 . 5 p F NOTES: 1. Typical values are for T A =+25oC and nominal voltage. 2. Operating current measured in a CDP1802 system at 3.2MHz with outputs floating. 3. I OL = IOH = 1µA. Dynamic Electrical Specifications At TA = -40oC to +85oC, VDD = 5V ±5%, VIH = 0.7 VDD, VIL = 0.3 VDD, tR, tF = 20ns, CL = 100pF PARAMETER SYMBOL VDD (V) (NOTE 1) TYP MAX UNITS Propagation Delay Time: MRD or CS to DO t ED 5 150 225 ns MRD or CS to DB t EB 5 150 225 ns DI to DB t IB 5 100 150 ns DB to DO t BO 5 100 150 ns NOTE: 1. Typical values are for T A = 25oC and nominal voltages. CDP1857C