The HT23C020 is a read-only memory with
high performance CMOS storage device whose
2048K of memory is arranged into 262144
words by 8 bits.
For applica tion flexibility, the chip enable and
output enabl e control pins can be selected a s
active high or active low. This flexibility not
only allows easy interface with most microprocessors, but also eliminates bus contention in
HT23C020
CMOS 256K×8-Bit Mask ROM
•
262144×8 bits of mask ROM
•
Mask option s: chip enab le CE/CE/OE1/OE1,
CE1/
CE1/OE2/OE2/NC and output enable
OE/
•
•
•
•
multiple bus mi cropro cessor syste ms. An add itional feature of the HT23C020 is its ability to
enter the standb y mode wh enever the chip enable (CE/
ducing current consumption to below 30
combination of these functions make the chip
suitable for high density low power memory
applications.
CE1/
VSSINegative power supply
VCCIPositive power supply
OE/NCIOutput enable input
OE/
NC—No connection
Operation Truth Table
ModeCE /CECE1/CE1OE/OEA0~A17D0~D7
ReadH/LH/LH/LValidData Out
DeselectH/LH/LL/HXHigh Z
StandbyL/HXXXHigh Z
StandbyXL/HXXHigh Z
Note: H=V
, L=VIL, X=VIH or V
IH
IL
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HT23C020
Absolu te Maximum Ra tin g s*
Supply Voltage.................................–0.3V to 6VStorage Temperature.................–50°C to 125°C
Input Voltage........................–0.3V to V
*Note: These are stress ra tings on ly. Stresses exceeding the range specified under “Abso lute Maxi -
mum Ratings” ma y cause substantial damage to the device. Functional operation of this
device at other conditions beyond those listed in the specification is not implied and prolonged
exposure to extreme condition s may affect device reliability.
D.C. Characteristics
Supply voltage: 2.7V~3.6VTa=–40°C to 85°C
+0.3VOperating Temperature ..............–40°C to 85°C
Input High Voltage3V—2.0—V
Output Low Voltage3VIOL= 2.1mA——0.4V
Output High Voltage3VIOH= –0.4mA2.4—V
Input Leakage Current3VVIN= 0 to V
Output Leakage Current3VV
Standby Current3V
Standby Current3V
Input Capacitance (See note)—f= 1MHz——10pF
Output Capacitance (See note)—f = 1MHz——10pF
Test Conditions
V
CC
Conditions
O/P Unload,
f= 5MHz
= 0 to V
OUT
CE=V
IL
CE=V
IH
≤0.2V
CE
CE≥VCC-0.2V
CC
CC
Note: These parameters are periodically sampled but not 100% tested.
Input High Voltage5V—2.2—V
Output Low Voltage5VIOL= 3.2mA——0.4V
Output High Voltage5VIOH= –1mA2.4—V
Input Leakage Current5VVIN= 0 to V
Output Leakage Current5VV
Standby Current5V
Standby Current5V
Input Capacitance (See note)—f= 1MHz——10pF
Output Capacitance (See note)—f = 1MHz——10pF
Test Conditions
V
CC
Conditions
O/P Unload,
f= 5MHz
= 0 to V
OUT
CE=V
IL
CE=V
IH
≤0.2V
CE
CE≥VCC-0.2V
CC
Min.Typ.Max. Unit
——25mA
—0.8V
SS
——10µA
CC
——10µA
——1.5mA
——30
CC
CC
V
V
µA
Note: These parameters are periodically sampled but not 100% tested.
A.C. CharacteristicsTa=–40°C to 85°C
=2.7V~3.6VVCC=4.5V~5.5V
V
SymbolParameter
CC
Min.Max.Min.Max.
t
CYC
t
AA
t
ACE
t
AOE
t
OH
t
OD
t
OE
Cycle Time250—150—ns
Address Access Time—250—150ns
Chip Enable Access Time—250—150ns
Output Enable Access Time—150—80ns
Output Hold Time——10—ns
Output Disable Time (See Note)———70ns
Output Enable Time (See Note)——10—ns
Note: These parameters are periodically sampled but not 100% tested.
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Unit
Page 5
A.C. test conditions
Output load: see figure right
Input rise and fall time: 10ns
Input pulse levels : 0.4V to 2.4V
Input and output timing reference levels:
0.8V and 2.0V (V
=5V), 1.5V (VCC=3V)
CC
Functional Description
The HT23C020 has two modes, namely data
read mode and standby mode, controlled by
CE/
CE/OE1/OE1,CE1/CE1/OE2/OE2/NC and
OE/
OE/NC inputs.
•
Standby mode
The HT23C020 has lower current consumption,
controlled by the chip enable input (CE/
CE1/
CE1). When a low/high level is applied to
the CE/
output enable (OE/
CE or CE1/CE1 input, regardless of the
OE/NC) states, the chip will
enter the standby mode.
CE and
HT23C020
Output load circuit
•
Data read mode
When both the chip enable (CE/
CE1/
CE1/OE2/OE2/NC) and the output en-
able (OE/
OE/NC) are active, the chip is in
data read mode. Otherwise, active CE/
CE1/
CE1 and inactive OE/OE/NC result in
deselect mode. The output will remain in Hi-Z
state.
CE/OE1/OE1,
CE,
Timing Diagrams
•
Propagation delay due to address (CE/CE/OE1/OE1, CE1/CE1/OE2/OE2
and OE/
•
Propagation delay due to chip and output enable (address valid)
OE are active)
521st Aug ’98
Page 6
Characteristic Curves
HT23C020
621st Aug ’98
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HT23C020
721st Aug ’98
Page 8
HT23C020 MASK ROM ORDERING SHEET
Custom:
Input Medium:
EPROM DISK File (Mail Address: romfile@holtek.com.tw) OTHER
HT23C020
User No.Type/Ref. NameQ’tyCheck Sum
Control Pin and Package Form Option:
(a) 32 Pin Type Pin 22:
Pin 31:
Pin 24:
(b) Package Form:
Companion User No.
Package Marking :
Delivery Date : Q’ty: