ATMEL AT27C520-90XI, AT27C520-90XC, AT27C520-90TI, AT27C520-90TC, AT27C520-90SI Datasheet

Features

•8-Bit Multiplexed Addresses/Outputs

•Fast Read Access Time - 70 ns

•Low Power CMOS Operation

–20 mA max. Active at 5 MHz

•20-Lead TSSOP Package

•20-Lead SOIC Package

•28-Lead TSOP Package

•5V ± 10% Supply

•High Reliability CMOS Technology

–2,000V ESD Protection

–200 mA Latchup Immunity

• Rapid™ Programming Algorithm - 50 μs/byte (typical)

•CMOS and TTL Compatible Inputs and Outputs

•Integrated Product Identification Code

•Commercial and Industrial Temperature Range

Description

The AT27C520 is a low-power, high performance 524,288 bit one-time programmable read only memory (OTP EPROM) organized 64K by 8 bits. It incorporates latches for the 8 lower order address bits to multiplex with the 8 data bits. This minimizes system chip count, reduces cost, and simplifies the design of multiplexed bus systems. It requires only one 5V power supply in normal read mode operation. Any byte can be accessed in less than 70 ns, eliminating the need for speed reducing WAIT states on high performance microprocessor systems.

Atmel’s scaled CMOS technology provides high speed, lower active power consumption, and significantly faster programming. Power consumption is typically only 8 mA in Active Mode.

The AT27C520 is available in 173 mil, 20-pin TSSOP; 300 mil, 20-pin SOIC; and 28pin TSOP, one-time programmable (OTP) plastic packages.

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Pin Configurations												TSSOP Top View
	Pin Name			Function								A10					1			20		A8
												A12					2			19		AD1
	A8 - A15			Addresses
												A14					3			18		AD3
												ALE					4			17		AD5
	AD0 - AD7			Addresses/Outputs
												VCC					5			16		AD7
											OE/VPP						6			15		GND
	OE /VPP			Output Enable/VPP								A15					7			14		AD6
												A13					8			13		AD4
	ALE			Address Latch Enable
												A11					9			12		AD2
												A9					10			11		AD0
				TSOP Top View
													SOIC Top View
	A10		22	21				A8
	NC		23	20				NC
	NC		24	19				NC
									OE/VPP							1				20		VCC
	A12		25	18				AD1				A15				2				19		ALE
	A14		26	17				AD3
												A13				3				18		A14
	ALE		27	16				AD5
												A11				4				17		A12
	VCC		28	15				AD7
												A9				5				16		A10
OE/VPP			1	14				GND
												AD0				6				15		A8
	A15		2	13				AD6
												AD2				7				14		AD1
	A13		3	12				AD4
	A11		4	11				AD2				AD4				8				13		AD3
	NC		5	10				NC				AD6				9				12		AD5
	NC		6	9				NC				GND				10				11		AD7
	A9		7	8				AD0

512K (64K x 8) Multiplexed Addresses/ Outputs

OTP EPROM

AT27C520

Rev. 0752C-C–01/98

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With 64K byte storage capability, the AT27C520 allows firmware to be stored reliably and to be accessed by the system without the delays of mass storage media.

Atmel's 27C520 has additional features to ensure high quality and efficient production use. The Rapid™ Programming Algorithm reduces the time required to program the part and guarantees reliable programming. Programming time is typically only 50 μs/byte. The Integrated Product Identification Code electronically identifies the device and manufacturer. This feature is used by industry standard programming equipment to select the proper programming algorithms and voltages.

System Considerations

Switching under active conditions may produce transient voltage excursions. Unless accommodated by the system design, these transients may exceed data sheet limits, resulting in device non-conformance. At a minimum, a 0.1 μF high frequency, low inherent inductance, ceramic capacitor should be utilized for each device. This capacitor should be connected between the VCC and Ground terminals of the device, as close to the device as possible. Additionally, to stabilize the supply voltage level on printed circuit boards with large EPROM arrays, a 4.7 μF bulk electrolytic capacitor should be utilized, again connected between the VCC and Ground terminals. This capacitor should be positioned as close as possible to the point where the power supply is connected to the array.

Block Diagram

	VCC			8
	GND
	OE/VPP		OE, ALE, AND	OUTPUT
	ALE	PROGRAM LOGIC
				BUFFERS
		LATCHES	Y DECODER	Y-GATING
	AD7 - AD0
			X DECODER	CELL MATRIX
		8
	A15 - A8
				IDENTIFICATION

2	AT27C520

Absolute Maximum Ratings*

Temperature Under Bias	................................ -55°C to +125°C
Storage Temperature .....................................	-65°C to +150°C
Voltage on Any Pin with	-2.0V to +7.0V(1)
Respect to Ground .........................................
Voltage on A9 with	-2.0V to +14.0V(1)
Respect to Ground ......................................
VPP Supply Voltage with	-2.0V to +14.0V(1)
Respect to Ground .......................................

AT27C520

*NOTICE: Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

Note: 1. Minimum voltage is -0.6V DC which may undershoot to -2.0V for pulses of less than 20 ns. Maximum output pin voltage is VCC + 0.75V DC which may overshoot to +7.0V for pulses of less than 20 ns.

Operating Modes

Mode/Pin	ALE	OE/VPP				A8 - A15		AD0 - AD7
Read	VIL		VIL			Ai		DOUT
Output Disable	V /V		V		IH	X(1)		High Z/A0 - A7
	IL IH
Address Latch Enable	VIH		VIH			X		A0 - A7
Rapid Program(2)	V		V			Ai		D	IN
	IH			PP
Product Identification(3)						A9 = VH(4)
	V		V		IL	A8 = V or V	IL	Identification Code
	IL					IH
						A10 - A15 = VIL
Notes: 1. X can be VIL or VIH.

2.Refer to Programming Characteristics.

3.VH = 12.0 ± 0.5V.

4.Two identifier bytes may be selected. All A8 - A15 inputs are held low (VIL), except A9 which is set to VH and A8 which is toggled low (VIL) to select the Manufacturer’s Identification byte and high (VIH) to select the Device Code byte.

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