SN74BCT2414N [TI]
具有片上电源监控器的双路 2 线路至 4 线路存储器解码器 | N | 20 | 0 to 70;
| 型号： | SN74BCT2414N |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | 具有片上电源监控器的双路 2 线路至 4 线路存储器解码器 | N | 20 | 0 to 70 驱动 监控 存储 解码器 驱动器 |
| 文件： | 总9页 (文件大小：130K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SN74BCT2414
MEMORY DECODER
WITH ON-CHIP SUPPLY VOLTAGE MONITOR
SCBS059B – MARCH 1989 – REVISED NOVEMBER 1993
DW OR N PACKAGE
(TOP VIEW)
• BiCMOS Design Substantially Reduces
Standby Current
• Two Independent 2-Line to 4-Line Decoders
VS
SD
1A
2A
1B
V
V
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
CC
bat
or One 3-Line to 8-Line Decoder
• Separate Enable Inputs for Easy Cascading
1Y0
1Y1
1Y2
1Y3
2Y0
• Two Supply Voltage Terminals (V
and
CC
V
)
bat
2B
• Built-In Supply-Voltage Monitor for V
• Automatic Cut Off of Outputs During
CC
1G
2G
G
13 2Y1
12 2Y2
V
Fail
CC
• Package Options Include Plastic
11
GND
2Y3
Small-Outline (DW) Packages and Standard
Plastic 300-mil DIPs (N)
description
The SN74BCT2414 is a decoder specially designed to be used in memory systems with battery backup during
power failure. The two independent 2-line to 4-line decoders with separate and common control inputs may be
externally cascaded to implement a 3-line to 8-line decoder.
The circuit has two supply voltage inputs: the voltage monitor (bandgap) is powered via the V
terminal; the
CC
internallogicofthecircuitispoweredviatheV terminal.IncaseV dropsbelow3.65V(nominal),thevoltage
bat
CC
monitor forces the voltage-control (VS) and decoder outputs (Y) to the high level. VS may be used to disconnect
the supply voltage of the memories (V ) from the system supply. This output is switched off when the on-chip
bat
supply voltage monitor detects a power failure.
The SN74BCT2414 is characterized for operation from 0°C to 70°C.
Copyright 1993, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
2–1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74BCT2414
MEMORY DECODER
WITH ON-CHIP SUPPLY VOLTAGE MONITOR
SCBS059B – MARCH 1989 – REVISED NOVEMBER 1993
†
logic symbol
VCOMP
X > 3.65 V
20
1
V
CC
VS
2
9
&
SD
G
EN
18
17
16
15
X/Y
0
1
2
3
1Y0
1Y1
1Y2
1Y3
3
5
7
1A
1B
1
2
1G
EN
14
13
12
11
X/Y
0
1
2
3
2Y0
2Y1
2Y2
2Y3
4
6
8
2A
1
2B
2G
2
EN
†
This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
2–2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74BCT2414
MEMORY DECODER
WITH ON-CHIP SUPPLY VOLTAGE MONITOR
SCBS059B – MARCH 1989 – REVISED NOVEMBER 1993
logic diagram (positive logic)
20
V
CC
VCOMP
1
VS
19
V
bat
18
2
3
1Y0
SD
1A
17
1Y1
16
1Y2
5
7
15
1B
1G
1Y3
8
9
2G
G
14
2Y0
4
6
13
2A
2B
2Y1
12
2Y2
11
2Y3
2–3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74BCT2414
MEMORY DECODER
WITH ON-CHIP SUPPLY VOLTAGE MONITOR
SCBS059B – MARCH 1989 – REVISED NOVEMBER 1993
FUNCTION TABLES
INPUTS
CONTROL
OUTPUTS
SELECT
G
H
X
X
L
1G
X
H
X
L
SD
X
1B
X
X
X
L
1A 1Y0 1Y1 1Y2 1Y3
X
X
X
L
H
H
H
L
H
H
H
H
L
H
H
H
H
H
L
H
H
H
H
H
H
L
X
L
H
H
H
H
L
L
L
H
L
H
H
H
L
L
H
H
H
H
L
L
H
H
INPUTS
OUTPUTS
2A 2Y0 2Y1 2Y2 2Y3
CONTROL
SELECT
G
H
X
X
L
2G
X
SD
2B
X
X
X
L
X
X
L
X
X
X
L
H
H
H
L
H
H
H
H
L
H
H
H
H
H
L
H
H
H
H
H
H
L
H
X
H
H
H
H
H
H
H
H
L
L
H
L
H
H
H
L
H
H
H
H
L
H
H
NOTE: For a 3-line to 8-line decoder, the following pins must
be shorted: 1G to 2G, 1A to 2A and 1B to 2B.
†
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage range, V
Supply voltage range, V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
bat
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –1.5 V
Supply voltage V
with respect to V
CC
bat
Input voltage range, V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to V
+ 0.5 V
I
CC
Off-state output voltage range at VS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
Voltage range applied to any Y output in the power-off state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
Voltage applied to any Y output in the power-off state with respect to V
. . . . . . . . . . . . . . . . . . . . . . . . 0.5 V
bat
Operating free-air temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C
Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C
†
Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability
2–4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74BCT2414
MEMORY DECODER
WITH ON-CHIP SUPPLY VOLTAGE MONITOR
SCBS059B – MARCH 1989 – REVISED NOVEMBER 1993
recommended operating conditions
MIN NOM
MAX
5.5
UNIT
V
V
V
V
V
Supply voltage
4.5
4.5
2
5
5
CC
bat
IH
Supply voltage
5.5
V
High-level input voltage
Low-level input voltage
Input clamp current
High-level output current
V
0.8
–18
–400
8
V
IL
I
I
mA
µA
IK
OH
OL
t
Y outputs
I
Low-level output current
mA
VS outputs
20
t
Input transition time
0
0
10
ns/V
T
A
Operating free-air temperature
70
°C
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
†
PARAMETER
TEST CONDITIONS
MIN TYP
MAX
UNIT
V
V
CC
V
bat
V
bat
V
bat
V
bat
= 4.5 V,
I = –18 mA
–1.2
V
IK
I
I
I
I
I
I
I
= – 20 µA
= – 400 µA
= – 50 µA
= 4 mA
4.4
3.5
1.8
OH
OH
OH
OL
OL
OL
= V
= 4.5 V
CC
V
OH
V
V
= 2 V, V
= 0,
CC
0.4
0.5
1
All except VS
VS
= V
= V
= 4.5 V
= 4.5 V,
CC
CC
V
V
= 8 mA
OL
= 20 mA
‡
T
3.65
V
I
I
I
I
I
V
V
V
V
V
= V
= V
= V
= 5.5 V,
= 5.5 V,
= 5.5 V,
V = 5.5 V
100
±20
±20
1
µA
µA
µA
µA
mA
I
bat
bat
bat
bat
bat
CC
CC
CC
I
V = 2.7 V
I
IH
V = 0.5 V
I
IL
VS
= 4.5 V,
V
V
= 0
OH
CC
= 2.25 V
O
§
= V
= 5.5 V,
–30
–200
3
O
CC
CC
Outputs high
Outputs low
I
V
bat
V
bat
V
bat
V
bat
V
bat
= V
= 5.5 V
mA
CC
bat
3
= 2.5 V,
V
CC
= 0
1
10
µA
I
Outputs high
Outputs low
20
= V
= V
= V
= 5.5 V
= 5 V,
= 0
CC
CC
CC
3
mA
pF
C
C
V = 0 or 3 V
I
4
6.5
5
i
Any Y
VS
pF
o
†
‡
§
All typical values are at V
= 5 V, T = 25°C.
A
CC
CC
This value represents the V
monitor threshold voltage. Typical range is from 3.5 V to 3.8 V.
This output condition has been chosen to produce a current that closely approximates one half of the short-circuit output current, I . Not more
than one output should be tested at a time, and the duration of the test should not exceed one second.
OS
2–5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74BCT2414
MEMORY DECODER
WITH ON-CHIP SUPPLY VOLTAGE MONITOR
SCBS059B – MARCH 1989 – REVISED NOVEMBER 1993
switching characteristics (see Note 1)
V
C
= 4.5 V to 5.5 V,
= 50 pF,
V
C
= 5 V,
= 50 pF,
CC
L
CC
L
R1 = 500 Ω,
R1 = 500 Ω,
R2 = 500 Ω,
T
A
FROM
(INPUT)
TO
(OUTPUT)
PARAMETER
UNIT
R2 = 500 Ω,
T
A
†
= MIN to MAX
= 25°C
TYP
5
MIN
1
MAX
10
10
9
MIN
1
MAX
t
t
t
t
t
t
12
12
10
11
12
12
PLH
PHL
PLH
PHL
PLH
PHL
A or B
Any Y
Any Y
Any Y
ns
ns
ns
2
5.8
2
1
4.5
1
Any G
SD
2
5.5
9
2
2
6.5
11
11
2
2
6.5
2
switching characteristics (see Note 1)
V
C
= 4.5 V to 5.5 V,
= 50 pF,
V
C
= 5 V,
= 50 pF,
CC
L
CC
L
R1 = 500 Ω,
R2 = 500 Ω,
T
A
R1 = 500 Ω,
R2 = 500 Ω,
T
A
FROM
PARAMETER
TO
(OUTPUT)
UNIT
(INPUT)
†
= 25°C
TYP
25
= MIN to MAX
MIN
10
MAX
50
MIN
10
MAX
250
250
250
250
t
t
t
t
PLH
PHL
PLH
PHL
V
V
Any Y
VS
ns
ns
CC
15
45
100
50
15
10
28
10
CC
20
50
100
20
†
For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
NOTE 1: Load circuits and voltage waveforms are shown in Section 1.
2–6
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
SN74BCT2414
MEMORY DECODER
WITH ON-CHIP SUPPLY VOLTAGE MONITOR
SCBS059B – MARCH 1989 – REVISED NOVEMBER 1993
APPLICATION INFORMATION
A typical application circuit for a battery-buffered memory in a microcomputer system is shown in Figure 1 which uses
the SN74BCT2414. When power fails, the supply-voltage supervisor (TL7705) resets the microcomputer and
disables the memory by switching the shutdown input SD of the memory decoder to a logic zero. All memory decoder
outputs are forced to a logic one. Abnormal write commands from the microprocessor, which may be issued during
further voltage breakdown, no longer affect the contents of the memory. When the system supply voltage becomes
lower than approximately 3.65 V, the voltage monitor inside the SN74BCT2414 memory decoder disconnects the
input buffers of this circuit from the decoding logic internally and keeps all outputs at a logic one. The VS output is
also switched off, disconnecting the system supply voltage from the memory circuits. During this low-voltage
condition, the memory decoder and the memory circuits are supplied by the battery.
Microprocessor
8
D0 – D7
D3
V
CC
R3
A0 – A15
16
R1
DBIN
WE
Q1
D1
1N4148
R2
1 kΩ
RESET
SN74BCT2414
VS
V
CC
bat
V
A15
A14
A13
V
CC
5 V
1G
2G
1B
1Y0
1Y1
1Y2
1Y3
2B
1A
10 kΩ
TL7705A
2Y0
2Y1
2Y2
2Y3
V
CC
2A
SD
G
RES
SENSE
RESIN
CE
VREF
C
t
GND
A0 – A12
OE
0.1 µF
0.1 µF
WR
8- × 8K-Byte CMOS RAM
For further information on this device, please contact factory.
Figure 1. Memory System With Battery Backup
2–7
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
2–8
IMPORTANT NOTICE
Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF
DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL
APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR
WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER
CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO
BE FULLY AT THE CUSTOMER’S RISK.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.
Copyright 1998, Texas Instruments Incorporated
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