CDP1857C 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, whenMRD = 1, it enables the three-state bus drivers (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 terminals. The CDP1857 can be used as a bidirectional bus buffer by connecting the corresponding DI and DO terminals (Figure 1). The MRD output signal from the 1800-series microprocessor has the correct polarity to control the CDP1857 when it is used as I/O bus buffer/separator. Therefore, the 1800-series microprocessor MRD signal can be connected directly to theMRD 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
Functional Diagram For CDP1857
Ordering Information
NUMBER TEMP. RANGE PACKAGE PKG. NO. CDP1857CE -40 oC to +85oC PDIP E16.3 CDP1857CD -40 oC to +85oC SBDIP D16.3 TABLE 1. CDP1857 FUNCTION FOR I/O BUS SEPARATOR
0 X High Impedance High Impedance
File Number 1192.2CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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 only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Static Electrical SpecificationsAt 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 50 µA Output Low Drive (Sink) Current I OL 0.4 0, 5 5 1.6 3.2 - mA Output High Drive (Source) Current IOH 4.6 0, 5 5 -1.15 -2.3 - mA 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 pF NOTES: 1. Typical values are for TA =+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 SpecificationsAt 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 TA = 25oC and nominal voltages. CDP1857C