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6540 ROM used in Commodore and Amiga equipment

IC number

6540

IC function

16 kbit (2k×8) ROM with five chip selects

Related components

16 kbit (2k×8) ROM with two chip selects

Component documentation

IC number	Manufacturer	Documentation
6540	MOS Technology	Preliminary Datasheet July 1977

Component versions

IC number	Package	Access time
6540	28-pin DIP	300 ns

Programmed components

IC number	CBM part number	CBM part description	Chip description

Positions

Device	Position

Pinout

Pin	Type	Name
1	Power	VSS
2..4	Input	CS5..CS3
5..10	Input	A0..A5
11	Input	A9
12	Power	VCC
13..15	Input	A8..A6
16	Input	Ø2
17	Input	CS1
18	Input	A10
19..26	I/O	DB7..DB0
27	Input	CS2
28	N/C	NC

Details

The 6540 16K Read Only Memory is a monolithic N-channel metal-gate array manufactured with a low-threshold process and utilizing both enhancement and depletion mode MOS transistors.

Three-state outputs provide bus-compatibility with microprocessor-based memory systems. The ROM's are organized as 2048 words of 8 bits each.

Mask options provide user specification of chip select equations, allowing addressing anywhere within a 65K memory space without external decode circuitry.

Features

Interfaces with TTL, DTL or MOS

Single +5V supply

High speed operation (300 ns access)

Three-state outputs

Complete address control

No external components required

No system slow-down

Five chip selects

Block diagram

Maximum ratings

Maximum ratings

Rating	Symbol	Voltage	Unit
Supply Voltage	VCC	-0.3 to +7.0	V
Input/Output Voltage	VIN	-0.3 to +7.0	V
Operating Temperature	TOP	0 to 70	°C
Storage Temperature	TSTG	-55 to +150	°C

Electrical Characteristics

Electrical Characteristics (VCC = 5.0 V ± 5% VSS = 0 V; TA = 25°C)

Characteristic	Symbol	Min.	Typ.	Max.	Unit
Input High Voltage	VIH	VSS+2.0	-	VCC	V
Input Low Voltage	VIH	VSS-.3	-	VSS+.8	V
Input Leakage Current (A0-A10, CS1, CS2, Ø2)	IIN		1.0	2.5	µA
Input Current for High Impedance (Three State) Outputs: VIN = 0.4V to 2.4V	ITSI		1.0	10	µA
Output High Voltage: VCC = Min ILOAD <= -100µA	VOH	VSS+2.4			V
Output Low Voltage: VCC = Min ILOAD <= 1.6mA	VOL			VSS+.4	V
Output Low Current (sinking) VOL <= .4V	IOL	1.6			mA
Supply Current	ICC		110	150	mA

Timing

Copyright © 2005-2010 Ronald van Dijk - All rights reserved
Sources:
MOS Technology 6540/6541 Preliminary Datasheet July 1977
Last update: 13 May 2010