IZ1278U
1
10/12-
DIGIT
S
ELECTABLE
D
ESK
T
OP
C
ALCULATOR
The IZ1278 is a single chip CMOS LSI with 10-digit or 12-digit arithmetic operation, 2-
memory, extraction-of-square-root, percentage, MU calculation and auto power off
function, designed for FEM LCD operation with a 1.5V power supply.
FUNCTIONS
10/12 digits selectable display by diode option
Four standard functions (+, -, , )
Memory, GT (grand total) memory calculations
Auto-percentage calculations (add on, discount)
Constant calculations
Square root calculations
Chain calculations
MU calculations
Power calculations
Rough estimate calculations
Change sign
FEATURES
Single chip CMOS construction
Floating point or memory mode (sw selectable)
Fixed point (0,2,3,4) and adding point mode
Rounding switches (rounding up, down and off)
Leading and trailing zero suppression
Punctuation comma display for thousands
LCD direct drive
Over flow indication: "E"
On-chip key board debouncing and encoding
Wide supply voltage range (1.2V ~ 2.0V)
Very low power consumption (7w TYP)
PKG type: 64 QFP and bare chip available
Symbols: GT, M, -, E, K, +, -, ,
ABSOLUTE MAXIMUM RATINGS ( T
a
= 25
o
C )
Characteristic Symbol Value
Unit
Terminal Voltage
V
DD
- 0.3 ~ + 2.0
V
V
IN
- 0.3 ~ V
DD
+
0.3 V
Operating Temperature
T
a
0 ~ + 40
o
C
Storage Temperature
T
stg
- 55 ~ + 125
o
C
ELECTRICAL CHARACTERISTICS
(T
a
= 25
o
C, V
DD
= 1.5V, V
SS
= 0V unless otherwise specified)
Characteristic Symbol
Test
Condition Min
Typ
Max
Unit
High Input Voltage(K3~K10)
V
IH
V
DD
-
0.4
V
DD
V
(K11~K12)
V
IH
V
CC
-
0.4 V
CC
Low Input
(KI)
V
IL
V
SS
0.4
V
Voltage (K3~K12)
High Output Voltage(K1~K8)
V
OH
V
DD
-
0.2 V
DD
V
Low Output Voltage(K1~K8)
V
OL
V
SS
0.2
V
Key Pull
Down
(KI) R
pd1
V
out
= 0.3V
0.5
1
1.5
K
Resistor
(K1 ~ K10)
R
pd2
10
17
28
Key Pull Up
(KI)
R
pu1
V
out
= 1.2V
145
170
195
Resistor
(K1 ~ K10)
R
pu2
0.6
1.2
1.9
K
(K11 ~ K12)
R
pu3
V
out
= 2.7V
250
400
550
High Output Voltage (LCD,
COM)
V
OH
V
CC
-0.2 V
CC
V
"M" Output Voltage (LCD,
COM)
V
OM
V
DD
-0.2 V
DD
V
Low Output Voltage (LCD,
V
OL
V
SS
0.2
V
IZ1278U
2
Characteristic Symbol
Test
Condition Min
Typ
Max
Unit
COM)
OSC Frequency
F
dis
Stand-by 5.4
9.0
12.6
KHz
F
opr
Operating 28.8
48
67.2
Frame Frequency
F
f
Stand-by 56.3
93.8
131
Hz
Operating Voltage
V
DD
1.2
1.5
2.0
V
I
OFF
Display is off
1
Supply Current
I
DIS
Display is on
4.4
6.5
A
I
OP
Operating
7.0
15
FUNCTIONAL DESCRIPTION
Decimal point system
Floating point for momentary mode by
TAB Selection.
Integral number : 10/12 digits leading
zero suppression. Zero shift.
Symbols M : memory display
E : error display
- : negative number
display
GT : negative number
display
+, -,
, : for rules operator
K : constant
Error detections (Parenthesis is in
case of 10 digits)
System errors occur when:
1) The division by zero.
2) The integral part of any memory
calculation result exceeds 12(10) digits.
3) The integral part of GT memory
contents exceeds 12 (10) digits.
Rough estimate calculation error
The integral part of any calculation-
four standard functions, percentage,
square or power calculations result
exceeds 12 digits
(10 digits).
Error indication
System error
Zero is displayed at first-digit and "E" sign is
indicated at symbol.
Rough estimate calculation error
The high-order 12 digits (10 digits) of any
calculation result is indicated together with "E" sign,
and the decimal point is displayed at the position
corresponding to 10
-12
(10
-10
) of the calculation
result also no zero shift is performed.
Error release
System error
Released by AC, C, CE key.
Rough estimate calculation error
AC, C key can release a rough estimate
calculation error and can clear calculation result at
once, also CE key can just only release error flag
`E' at first time and can clear calculation result at
second time.
Number entry
Numericals can be entered up to 12 digits (10
digits).
Numericals more then 13 digits (11 digits) are
ignored.
Memory protection
Under any error detection, the memory data
before error detection are protected.
Memory indication
If the memory data is not zero, "M" is indicated at
symbol position.
AUTO POWER OFF
IZ1278U
3
Power turns off after about 5 minutes
pass from the last key pressure.
SELECTION MODE SWITCH
FUNCTION
10-digits/12-digits mode depends on
K11 pin, please refer to application
circuit.
Fixed/floating decimal point mode and
ADD
2
mode are selection by rounding
switch.
The rounding switch should be so
composed that either one ` 4, 3, 2, 0,
ADD
2
` is selected.
Fix `F' mode
When TAB `F' is selected, both entered
numbers and calculation results follow
to floating decimal point system.
DP I = 0, 2, 3, 4 mode
The calculation results follow to fixed decimal point
system and I+1 decimal place is counted by TAB
`CUT', TAB `UP', TAB `5/4'.
Fix `CUT' mode
The number of i +1 decimal position is counted as
cutting away.
Fix `UP' mode
The number of i decimal position is counted as
added to `1'.
Fix `5/4' mode
When `+' and `-' operations are performed after a
number except decimal point is entered. The
calculation is executed as 1/100 value of number
being entered.
IZ1278U
4
KEY DESCRIPTION
0 ~ 9 00
Numerals input key
.
Decimal point key
ON/AC
AC
CE
Clear key
+ - x :
Four standard function key
%
Percent key
GT
Grand total memory key
M+
M-
Memory add and memory subtract key
MRC
Recall and clear memory
MR
MC
Recall memory, clear memory
Extraction of square root key
=
Enter key
+/-
Sign change key
Shift Right key
MU
Mark-up and mark-down key
OFF
Power off key
ON/AC: Power ON/All clear (system rest)
C: All except memory contents
CE: Entry clear such as only the entered data is cleared
* Recall the data in GT
GT flag is released by AC or C key
* When = key is pressed, the result of calculator is added to GT memory automatically
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