HANBit
HMNR28D(V)
5.0 or 3.3V, 16K bit (2 Kbit x 8) TIMEKEEPER NVSRAM
Part No. HMNR28D(V)
GENERAL DESCRIPTION
The HMNR28D(V) TIMEKEEPER SRAM is a 2Kb x 8 non-volatile static RAM and real time clock organized as 2,048
words by 8 bits. The special DIP package provides a fully integrated battery back-up memory and real time clock solution.
The HMNR28D(V) directly replaces industry standard 2Kbit x 8 SRAMs. It also provides the non-volatility of Flash without
any requirement for special WRITE timing or limitations on the number of WRITEs that can be performed.
FEATURES
■
INTEGRATED LOW POWER SRAM, REAL TIME CLOCK, POWER-FAIL CONTROL CIRCUIT, BATTERY and
CRYSTAL
■
BCD CODED YEAR, MONTH, DAY, DATE, HOURS, MINUTES, and SECONDS
■
AUTOMATIC POWER-FAIL CHIP DESELECT and WRITE PROTECTION VOLTAGES :
(V
PFD
= Power-fail Deselect Voltage)
–
HMNR28D : V
CC
= 4.5 to 5.5V
4.2V
≤
V
PFD
≤
4.5V
–
HMNR28DV: V
CC
= 3.0 to 3.6V
2.7V
≤
V
PFD
≤
3.0V
■
CONVENTIONAL SRAM OPERATION : UNLIMITED WRITE CYCLES
■
SOFTWARE CONTROLLED CLOCK CALIBRATION FOR HIGH ACCURACY APPLICATIONS
■
10 YEARS OF DATA RETENTION and CLOCK OPERATION IN THE ABSENCE OF POWER PIN and FUNCTION
COMPATIBLE WITH INDUSTRY STANDARD 2K x 8 SRAMS
■
SELF-CONTAINED BATTERY and CRYSTAL IN DIP PACKAGE
OPTIONS
w
Timing
70 ns
85 ns
MARKING
-70
-85
PIN ASSIGNMENT
A7
A6
A5
A4
A3
A2
A1
A0
DQ0
DQ1
DQ2
Vss
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
Vcc
A8
A9
/WE
/OE
A10
/CE
DQ7
DQ6
DQ5
DQ4
DQ3
24-pin Encapsulated Package
URL : www.hbe.co.kr
Rev. 0.0 (March, 2002)
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HANBit Electronics Co.,Ltd.
HANBit
FUNCTIONAL DESCRIPTION
HMNR28D(V)
The HMNR28D(V) is a full function, year 2000 compliant (Y2KC), real– time clock/calendar (RTC) and 2k x 8 non-volatile
static RAM. User access to all registers within the HMNR28D(V) is accomplished with a bytewide interface . The Real-
time clock (RTC) information and control bits reside in the sixteen upper most RAM locations. The RTC registers contain
century, year, month, date, day, hours, minutes, and seconds data in 24-hour BCD format. Corrections for the date of
each month and leap year are made automatically. The RTC clock registers are double buffered to avoid access of
incorrect data that can occur during clock update cycles. The double buffered system also prevents time loss as the
timekeeping countdown continues unabated by access to time register data.
The HMNR28D(V) also contains its own power-fail circuitry which deselects the device when the V
CC
supply is in an out of
tolerance condition. This feature prevents loss of data from unpredictable system operation brought on by low V
CC
as
errant access and update cycles are avoided.
BLOCK DIAGRAM
OSCILLATOR AND
CLOCK CHAIN
32.768KHz
CRYSTAL
16 x 8
TIMEKEEPER
REGISTER
A0 ~ A10
POWER
2,032 x 8
SRAM ARRAY
V
PFD
VOLTAGE SENSE
AND
SWITCHING
CIRCURITY
LITHIUM
CELL
DQ0 ~ DQ7
/CE
/WE
/OE
Vcc
A0-A10 : Address Input
/CE : Chip Enable
V
ss
: Ground
DQ0-DQ7 : Data In / Data Out
/WE : Write Enable
/OE : Output Enable
V
CC
: Power (+5V or +3.3V)
NC : No Connection
Vss
URL : www.hbe.co.kr
Rev. 0.0 (March, 2002)
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HANBit Electronics Co.,Ltd.
HANBit
Absolute Maximum Ratings
Symbol
T
A
T
STG
T
SLD
(1)
HMNR28D(V)
Parameter
AmbientOperatingTemperature
Storage Temperature(Vcc Off, Oscillator Off)
Lead Solder Temperature for 10 seconds
Input or Output Voltage
Supply Voltage
Output Current
Power Dissipation
HMNR28D
HMNR28DV
Value
0 to 70
-40 to 70
260
-0.3 to Vcc+0.3
4.5 to 5.5
3.0 to 3.6
20
1
Unit
°
C
°
C
°
C
V
V
V
mA
W
V
IO
V
CC
I
O
P
D
Note
: Permanent device damage may occur if Absolute Maximum Ratings are exceeded.
Functional operation should be restricted to the Recommended DC Operating Conditions detailed in this data sheet.
Exposure to higher than recommended voltage for extended periods of time could affect device reliability.
(1) Soldering temperature not to exceed 260° C for 10 seconds (Total thermal budget not to exceed 150° C for longer
than 30 seconds).
Caution
: Negative undershoots below
–
0.3V are not allowed on any pin while in the Battery Back-up mode.
Operating and AC Measurement Conditions
Parameter
V
CC
Supply Voltage
Ambient Operating Temperature
Load Capacitance (C
L
)
Input Rise and Fall Times
Input Pulse Voltages
Input and Output Timing Ref. Voltages
HMNR28D
4.5 to 5.5
0 to 70
100
≤
5
0 to 3
1.5
HMNR28DV
3.0 to 3.6
0 to 70
50
≤
5
0 to 3
1.5
Unit
V
°
C
pS
nS
V
V
AC Measurement Load Circuit
Note : 50pF for HMNR28DV
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Rev. 0.0 (March, 2002)
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HANBit Electronics Co.,Ltd.
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Capacitance
Symbol
C
IN
C
OUT
Note :
1.
2.
3.
(3)
HMNR28D(V)
Parameter
(1,2)
Min
Max
10
10
Unit
pF
pF
Input Capacitance
Input/Output Capacitance
Effective capacitance measured with power supply at 5V (HMNR28D) or 3.3V (HMNR28DV). Sampled only, not
100% tested.
At 25° C, f = 1MHz.
Outputs deselected.
DC Characteristics
Symbol
I
LI
I
LO
(2)
Parameter
Input Leakage Current
Output Leakage Current
Supply Current
Supply Current (Standby)
TTL
Supply Current (Standby)
CMOS
Battery Current OSC ON
Battery Current OSC
OFF
Input Low Voltage
Input High Voltage
Output Low Voltage
Test Condition
0V
≤
V
IN
≤
V
CC
(1)
HMNR28D
Min
Typ
Max
±
1
±
1
8
15
5
3
575
100
-0.3
2.2
0.8
VCC
+0.3
0.4
0.4
2.4
2.0
3.6
100
100
4.1
4.35
4.5
2.7
2.4
2.0
800
HMNR28DV
Min
Typ
Max
±
1
±
1
4
10
3
2
575
800
100
-0.3
2.0
0.8
VCC
+0.3
0.4
0.4
Unit
uA
uA
mA
mA
mA
nA
nA
V
V
V
V
V
0V
≤
V
OUT
≤
V
CC
Outputs open
/CE=V
IH
/CE=V
CC
-0.2
I
CC
I
CC1
I
CC2
I
BAT
V
IL
V
IH
I
OL
=2.1mA
I
OL
=10mA
I
OH
=-1.0mA
I
OUT2
=-1.0uA
V
OUT1
> V
CC
-0.3
V
OUT2
>V
BAT
-0.3
V
OL
V
OH
V
OHB
I
OUT1
I
OUT2
V
PFD
Output Low Voltage
(open drain) (4)
Output High Voltage
V
OH
Battery Back-up
V
OUT
Current (Active)
V
OUT
Current (Battery
Back-up)
Power-fail Deselect
Voltage
Battery Back-up
Switchover Voltage
Battery Voltage
3.6
70
100
2.9
V
PFD
-
3.0
V
mA
uA
V
V
SO
V
BAT
3.0
3.0
100
mV
3.0
V
V
Note: 1. Valid for Ambient Operating Temperature: TA =0 to 70° C or 40 to 85° ;
C
VCC = 4.5 to 5.5V or 3.0 to 3.6V (except where noted).
2. Outputs deselected.
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Rev. 0.0 (March, 2002)
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OPERATING MODES
HMNR28D(V)
The 24-pin, 600mil DIP Hybrid houses a controller chip, SRAM, quartz crystal, and a long life lithium button cell in a single
package. The clock locations contain the year, month, date, day, hour, minute, and second in 24 hour BCD format.
Corrections for 28, 29 (leap year-compliant until the year 2100), 30, and 31 day months are made automatically. Byte
7F8h is the clock control register. This byte controls user access to the clock information and also stores the clock
calibration setting. The seven clock bytes (7FFh-7F9h) are not the actual clock counters, they are memory locations
consisting of READ/WRITE memory cells within the static RAM array. The HMNR28D includes a clock control circuit which
updates the clock bytes with current information once per second. The information can be accessed by the user in the
same manner as any other location in the static memory array. The HMNR28D(V) also has its own Power-Fail Detect
circuit. This control circuitry constantly monitors the supply voltage for an out of tolerance condition.
When V
CC
is out of tolerance, the circuit write protects the TIMEKEEPER register data and SRAM, providing data security
in the midst of unpredictable system operation. As V
CC
falls, the control circuitry automatically switches to the battery,
maintaining data and clock operation until valid power is restored.
Operating Modes
Mode
Deselect
WRITE
READ
READ
Deselect
Deselect
VCC
4.5V to 5.5V
or
3.0V to 3.6V
V
SO
to V
PFD
(min)
≤
V
SO
(1)
/CE
VIH
VIL
VIL
VIL
X
X
/OE
X
X
VIL
VIH
X
X
/WE
X
VIL
VIH
VIH
X
X
DQ7
–
DQ0
High-Z
DIN
DOUT
High
High
High
Power
Standby
Active
Active
Active
CMOS
Standby
Battery Back-
up
Note : X = V
IH
or V
IL
; V
SO
= Battery Back-up Switchover Voltage.
URL : www.hbe.co.kr
Rev. 0.0 (March, 2002)
5
HANBit Electronics Co.,Ltd.
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