Motorola MCM44B256BSG15, MCM44B256BSG17, MCM44A256BSG17, MCM44A256BSG12, MCM44A256BSG15 Datasheet

MOTOROLA

SEMICONDUCTOR TECHNICAL DATA

Order this document by MCM44256B/D

4MB R4000 Secondary Cache Fast

Static RAM Module Set

Four MCM44256B modules comprise a full 4 MB of secondary cache for the R4000 processor. Each module contains nine MCM6729DWJ fast static RAMs for a cache data size of 256K x 36. The tag portion, dependent on word line size, contains either two MCM6729DWJ or one MCM6726DWJ fast static RAMs. All input signals, except A0 and WE are buffered using 74FBT2827 drivers with series 25 Ω resistors.

The MCM6729DWJ and MCM6726DWJ are fabricated using high±performance silicon±gate BiCMOS technology. Static design eliminates the need for internal clocks or timing strobes.

All 4MB R4000 supported secondary cache options are available.

•Single 5 V ± 10% Power Supply

•All Inputs and Outputs are TTL Compatible

•Fast Module Access Time: 12/15/17 ns

•Zero Wait±State Operation

•Unified or Split Secondary Cache is Supported

•Word Line Sizes of 4, 8, 16, and 32 are Available (See Ordering Information for Details)

•Decoupling Capacitors are Used for Each Fast Static RAM and Buffer, Along with Bulk Capacitance for Maximum Noise Immunity

•High Quality Multi±Layer FR4 PWB with Separate Power and Ground Planes

			PIN NAMES
	A0 ± A17 . . . .		. . . . . . . . . . . . Address Inputs
	WE . . . . . . . . . .		. . . . . . . . . . . . . Write Enable
	DCS . . . . . . . . .		. . . . . . . . . . . . . Data Enable
	TCS . . . . . . . . .		. . . . . . . . . . . . . . Tag Enable
	OE . . . . . . . . . .		. . . . . . . . . . . Output Enable
	DQ0 ± DQ35 . .		. . . . . . . Data Input / Output
	TDQ0 ± TDQ7		. . . TAG Data Input / Output
	VCC . . . . . . . . .		. . . . . . . + 5 V Power Supply
	VSS . . . . . . . . .		. . . . . . . . . . . . . . . . . Ground

For proper operation of the device, VSS must be connected to ground.

MCM44256B

Series

PIN ASSIGNMENT

80 LEAD SIMM Ð TOP VIEW

	VCC	2	1	VSS
			3	DQ0
	DQ1	4
			5	DQ2
	DQ3	6
	DQ5	8	7	DQ4
	VSS	10	9	DQ6
			11	DQ7
	DQ8	12
	DQ10	14	13	DQ9
	DQ12	16	15	DQ11
	DQ14	18	17	DQ13
	DQ15	20	19	VSS
	DQ17	22	21	DQ16
			23	DQ18
	DQ19	24
	DQ21	26	25	DQ20
	VSS	28	27	DQ22
			29	VCC
	DQ23	30
	DQ25	32	31	DQ24
	DQ27	34	33	DQ26
			35	DQ28
	DQ29	36
	DQ30	38	37	VSS
	DQ32	40	39	DQ31
	DQ34	42	41	DQ33
			43	DQ35
	VSS	44
			45
				WE
	A0	46
			47	A1
	A2	48
	A4	50	49	A3
	A6	52	51	A5
	VCC	54	53	VSS
			55	DCS
	OE	56
	A8	58	57	A7
	A10	60	59	A9
	VSS	62	61	A11
			63	A12
	A13	64
	A15	66	65	A14
	A17	68	67	A16
			69
				TCS
	TDQ0	70
	TDQ1	72	71	VSS
			73	TDQ2
	TDQ3	74
	TDQ5	76	75	TDQ4
			77	TDQ6
	TDQ7	78
			79	VCC
	VSS	80

11/19/97

MOTOROLA FAST SRAM	MCM44256B SERIES
Motorola, Inc. 1997
	1

BLOCK DIAGRAM

256K x 36 CACHE

TCS

DCS

OE

A1

A2

A3 ± A17

A0

DQ0 ± DQ35

WE

TDQ0 ± TDQ7

74FBT2827
DRIVER
36
8
TAG OPTIONS:
256K x 4
A0
A1	4 WORD
A2	LINE SIZE
A3 ± A17	256K x 8
E
W	TAG
G
DQ0 ± DQ3

256K x 4

E

G

A1

A2

A3 ± A17

A0

DQ0 ± DQ3

W

										128K x 8
								A0			8 WORD
								A1			LINE SIZE
								A2 ± A16			128K x 8
								E
											TAG
								W
								G
								DQ0 ± DQ7			(A0 NOT USED)

128K x 8

A0

16 WORD

LINE SIZE

A1

A2 ± A16

64K x 8

E

TAG

W

G

DQ0 ± DQ7

(A0, A1 NOT USED)

128K x 8

A0

32 WORD

A1

LINE SIZE

A2 ± A16

32K x 8

E

TAG

W

G

DQ0 ± DQ7

(A0, A1, A2 NOT USED)

MCM44256B SERIES	MOTOROLA FAST SRAM
2

ABSOLUTE MAXIMUM RATINGS (Voltages Referenced to VSS = 0 V)

Rating	Symbol	Value	Unit
Power Supply Voltage	VCC	± 0.5 to 7.0	V
Voltage Relative to VSS	Vin, Vout	± 0.5 to VCC + 0.5	V
Output Current (per I/O)	Iout	± 30	mA
Power Dissipation	PD	10	W
Temperature Under Bias	Tbias	± 10 to + 85	°C
Storage Temperature	Tstg	± 25 to +125	°C

NOTE: Permanent device damage may occur if ABSOLUTE MAXIMUM RATINGS are exceeded. Functional operation should be restricted to RECOMMENDED OPERATING CONDITIONS. Exposure to higher than recommended voltages for extended periods of time could affect device reliability.

This devices on this module contain circuitry to protect the inputs against damage due to high static voltages or electric fields; however, it is advised that normal precautions be taken to avoid application of any voltage higher than maximum rated voltages to these high±impedance circuits.

These BiCMOS memory circuits have been designed to meet the dc and ac specifications shown in the tables, after thermal equilibrium has been established. The module is in a test socket or mounted on a printed circuit board and transverse air flow of at least 500 linear feet per minute is maintained.

DC OPERATING CONDITIONS AND CHARACTERISTICS

(VCC = 5.0 V ± 10%, TA = 0 to + 70°C, Unless Otherwise Noted)

RECOMMENDED OPERATING CONDITIONS (Voltages Referenced to VSS = 0 V)

Parameter							Symbol	Min	Typ	Max	Unit
Supply Voltage (Operating Voltage Range)							VCC	4.5	5.0	5.5	V
Input High Voltage							VIH				V
(DQ0 ± 35, TDQ0 ±	7, WE, A0)							2.2	Ð	VCC + 0.3 V*
(A1 ± A17, OE, DCS, TCS)								2.0	Ð	VCC + 0.3 V*
Input Low Voltage							VIL	± 0.5**	Ð	0.8	V

*VIH (max) = VCC + 0.3 V dc; VIH (max) = VCC + 2 V ac (pulse width ≤ 20 ns).

**VIL (min) = ± 3.0 V ac (pulse width ≤ 20 ns).

DC CHARACTERISTICS

Parameter

Symbol

Min

Typ

Max

Unit

Input Leakage Current (All Inputs, Vin = 0 to VCC)

Ilkg(I)

± 10

μA

Output Leakage Current (G, xCS = VIH, Vout = 0 to VCC)

Ilkg(O)

± 10

μA

AC Supply Current (G, xCS = VIL, Iout = 0 mA)

ICCA

1750

mA

Output Low Voltage (IOL = + 8 mA)

VOL

0.4

V

OUtput High Voltage (IOH = ± 4.0 mA)

VOH

2.4

V

NOTE: Good decoupling of the local power supply should always be used.

CAPACITANCE (f = 1.0 MHz, dV = 3.0 V, TA = 25°C, Periodically Sampled Rather Than 100% Tested)

Parameter

Symbol

Typ

Max

Unit

Input Capacitance

(A0, WE)

Cin

110

pF

(A1 ± A17, OE, DCS, TCS)

Cin

10

pF

Input/Output Capacitance

Cout

10

pF

MOTOROLA FAST SRAM	MCM44256B SERIES
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