DS1743 Datasheet, PDF (1/17 Pages) Dallas Semiconductor – Y2KC Nonvolatile Timekeeping RAM

DS1743/DS1743P
Y2KC Nonvolatile Timekeeping RAM
www.dalsemi.com
FEATURES
Integrated NV SRAM, real time clock, crystal, power-
fail control circuit and lithium energy source
Clock registers are accessed identical to the static
RAM. These registers are resident in the eight top
RAM locations.
Century byte register
Totally nonvolatile with over 10 years of operation in
the absence of power
BCD coded century, year, month, date, day, hours,
minutes, and seconds with automatic leap year
compensation valid up to the year 2100
Battery voltage level indicator flag
Power-fail write protection allows for ±10% V_CC
power supply tolerance
Lithium energy source is electrically disconnected to
retain freshness until power is applied for the first time
DIP Module only
– Standard JEDEC bytewide 8k x 8 static RAM
pinout
PowerCap^ Module Board only
– Surface mountable package for direct connection
to PowerCap containing battery and crystal
– Replaceable battery (PowerCap)
– Power-On Reset Output
– Pin for pin compatible with other densities of
DS174XP Timekeeping RAM
ORDERING INFORMATION
DS1743P-XXX (5V)
-70 70 ns access
-100 100 ns access
blank 28-pin DIP Module
P
34-pin PowerCap Module
board*
*DS1743WP-XXX
(3.3V)
-120 120 ns access
-150 150 ns access
blank 28-pin DIP Module
P
34-pin PowerCap Module
board*
*DS9034PCX (PowerCap) Required:
(must be ordered separately)
PIN ASSIGNMENT
NC 1
A12 2
A7 3
A6 4
A5 5
A4 6
A3 7
A2 8
A1 9
A0 10
DQ0 11
DQ1 12
DQ2 13
GND 14
28 VCC
27 WE
26 CE2
25 A8
24 A9
23 A11
22 OE
21 A10
20 CE
19 DQ7
18 DQ6
17 DQ5
16 DQ4
15 DQ3
28-Pin Encapsulated Package
(700-mil Extended)
NC ¹
34
NC
NC ²
NC ³
RST ⁴
VCC
WE
5
6
OE ⁷
CE
DQ7
8
9
DQ6 ¹⁰
33
NC
32
NC
31
NC
30
A12
29
A11
28
A10
27
A9
26
A8
25
A7
DQ5 ¹¹
DQ4 12
24
A6
23
A5
DQ3 ¹³
22
A4
DQ2
DQ1
DQ0
14
21
15
16
X1 GND VBAT X2
20
19
A3
A2
A1
GND ¹⁷
18
A0
34-Pin Powercap Module Board
(Uses DS9034PCX Powercap)
PIN DESCRIPTION
A0-A12
- Address Input
CE
- Chip Enable
CE2
- Chip Enable 2 (DIP
Module only)
OE
- Output Enable
WE
- Write Enable
V_CC
GND
- Power Supply Input
- Ground
DQ0-DQ7 - Data Input/Output
NC
- No Connection
RST
- Power-On Reset Output
(PowerCap Module board only)
X1, X2
- Crystal Connection
V_BAT
- Battery Connection
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