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74F670 4 x 4 register file (3-State)
Product specification IC15 Data Handbook 1990 Jul 12
Philips Semiconductors
Philips Semiconductors
Product specification
4 x 4 register file (3-State)
74F670
FEATURES
• Simultaneous and Independent Read and Write operations • Expandable to almost any word size and bit length • 3-State outputs
DESCRIPTION
The 74F670 is a 16-bit 3-State Register File organized as 4 words of 4 bits each. Separate Read and Write Address and Enable inputs are available, permitting simultaneous writing into one word location and reading from another location. The 4-bit word to be stored is presented to four data inputs. The Write address inputs (WA and WB) determine the location of the stored word. The Write Address inputs should only be changed when the Write Enable input (WE) is High for conventional operation. When the WE is Low, the data is entered into the addressed location. The addressed location remains transparent to the data while the WE is Low. Data supplied at the inputs will be read out in true (non-inverting) form from the 3-State outputs. Data and address inputs are inhibited when the WE is High. Direct acquisition of data stored in any of the four registers is made possible by individual Read Address inputs (RA, RB). The addressed word appears at the four outputs when the Read Enable (RE) is Low. Data outputs are in the high impedance “off” state when the RE is High. This permits outputs to be tied together to increase the word capacity to very large numbers. Up to 128 devices can be stacked to increase the word size to 512 locations by tying the 3-State outputs together. Since the limiting factor for expansion is the output High current, further stacking is possible by tying pullup reisistors to the outputs to increase the IOH current available. Design of the Read Enable signals for the stacked devices must ensure that there is no overlap in the Low levels which cause more than one output to be active at the same time. Parallel expansion to generate n-bit words is accomplished by driving the Enable and address inputs of each device in parallel.
PIN CONFIGURATION
D1 D2 D3 RB RA Q3 Q2 GND 1 2 3 4 5 6 7 8 16 VCC 15 D0 14 WA 13 WB 12 WE 11 RE 10 Q0 9 Q1
SF01178
TYPE 74F670
TYPICAL PROPAGATION DELAY 6.5ns
TYPICAL SUPPLY CURRENT (TOTAL) 50mA
ORDERING INFORMATION
DESCRIPTION 16-pin plastic DIP 16-pin plastic SOL COMMERCIAL RANGE VCC = 5V ±10%, Tamb = 0°C to +70°C N74F670N N74F670D PKG DWG # SOT38-4 SOT162-1
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS D0 - D3 WA, WB RA, RB WE RE Q0–Q3 DESCRIPTION Data inputs Write address inputs Read address inputs Write Enable inputs Read Enable inputs Data output 74F(U.L.) HIGH/LOW 1.0/1.0 1.0/1.0 1.0/1.0 1.0/1.0 1.0/1.0 150/40 LOAD VALUE HIGH/LOW 20µA/0.6mA 20µA/0.6mA 20µA/0.6mA 20mA/0.6mA 20mA/0.6mA 3.0mA/24mA
NOTE: One (1.0) FAST Unit Load is defined as: 20µA in the High state and 0.6mA in the Low state.
1990 Jul 12
2
853-0014 99965
Philips Semiconductors
Product specification
4 x 4 register file (3-State)
74F670
LOGIC SYMBOL
14 13 5 4 15 1 2 3
LOGIC SYMBOL (IEEE/IEC)
14 0 13 WA WB RA RB D0 D1 D2 D3 5 0 4 12 Q0 Q1 Q2 Q3 11 2A 1 0 3 1A 1 RAM 4X4 0 3
12 11
WE RE
C4 [WRITE] EN [READ] 10 2A 9 7 6
10 VCC=Pin 16 GND=Pin 8
9
7
6
15 1 2 3
1A, 4D
SF01179
SF01180
WORD SELECT FUNCTION TABLE
WRITE MODE WB L L H WA L H L READ MODE RB L L H RA L H L H OPERATING MODE Word Selected Word 0 Word 1 Word 2 Word 3
WRITE MODE FUNCTION TABLE
INPUTS WE L L Dn L H INTERNAL LATCHES* L H OPERATING MODE
Write data
H H H H = High voltage level L = Low voltage level
READ MODE FUNCTION TABLE
INPUT RE L L H L X Z * = = = = = INTERNAL LATCHES* L H OUTPUT OPERATING MODE Qn L H Read
H X NC Data latched H = High voltage level L = Low voltage level NC= No change X = Don’t care * = The write address (WA and WB) to the “internal latches” must be stabled while WE is Low for conventional operation.
H X Z Disabled High voltage level Low voltage level Don’t care High impedance “off” state The selection of “internal latches” by Read Address (RA and RB) are not constrained by WE or RE operation.
1990 Jul 12
3
Philips Semiconductors
Product specification
4 x 4 register file (3-State)
74F670
LOGIC DIAGRAM
RE
11
RA 5 RB 4 12
WE
WB 13 WA 14
Q E D D3 3 E
Q E D
Q E D
Q D
6
Q3
Q E D D2 2 E
Q E D
Q E D
Q D
7
Q2
Q E D D1 1 E
Q E D
Q E D
Q D
9
Q1
Q E D D0 15 E
Q E D
Q E D
Q D
10
Q0
VCC=Pin 16 GND=Pin 8
SF01181
1990 Jul 12
4
Philips Semiconductors
Product specification
4 x 4 register file (3-State)
74F670
ABSOLUTE MAXIMUM RATINGS
(Operation beyond the limits set forth in this table may impair the useful life of the device. Unless otherwise noted these limits are over the operating free-air temperature range.) SYMBOL VCC VIN IIN VOUT IOUT Tamb Tstg Supply voltage Input voltage Input current Voltage applied to output in High output state Current applied to output in Low output state Operating .