1998 Microchip Technology Inc.
Preliminary
DS21206B-page 1
M
93C56A/B
FEATURES
Single supply 5.0V operation
Low power CMOS technology
- 1 mA active current (typical)
- 1
A standby current (maximum)
256 x 8 bit organization (93C56A)
128 x 16 bit organization (93C56B)
Self-timed ERASE and WRITE cycles (including
auto-erase)
Automatic ERAL before WRAL
Power on/off data protection circuitry
Industry standard 3-wire serial interface
Device status signal during ERASE/WRITE
cycles
Sequential READ function
100,000 E/W cycles guaranteed
Data retention > 200 years
8-pin PDIP and SOIC packages
Available for the following temperature ranges:
DESCRIPTION
The Microchip Technology Inc. 93C56A/B is a 2K-bit,
low-voltage serial Electrically Erasable PROM. The
device memory is configured as 256 x 8 bits (93C56A)
or 128 x 16 bits (93C56B). Advanced CMOS technol-
ogy makes this device ideal for low-power, nonvolatile
memory applications. The 93C56A/B is available in
standard 8-pin DIP and surface mount SOIC packages.
This device is only recommeded for 5V automotive
temperature applications. For all commercial and
industrial applications, the 93LC56A/B is recom-
mended.
PACKAGE TYPE
BLOCK DIAGRAM
- Automotive (E):
-40
C to
+125
C
93C56A/B
CS
CLK
DI
DO
1
2
3
4
8
7
6
5
V
CC
NC
NC
V
SS
CS
CLK
DI
DO
V
CC
NC
NC
V
SS
93C56A/B
SOIC
1
2
3
4
PDIP
8
7
6
5
V
CC
V
SS
DI
CS
CLK
DO
MEMORY
ARRAY
ADDRESS
DECODER
ADDRESS
COUNTER
DATA
REGISTER
OUTPUT
BUFFER
MEMORY
DECODE
LOGIC
CLOCK
GENERATOR
2K 5.0V Automotive Temperature Microwire
Serial EEPROM
Microwire is a registered trademark of National Semiconductor.
93C56A/B
DS21206B-page 2
Preliminary
1998 Microchip Technology Inc.
1.0
ELECTRICAL
CHARACTERISTICS
1.1
Maximum Ratings*
V
CC
...................................................................................7.0V
All inputs and outputs w.r.t.
V
SS
................ -0.6V to Vcc +1.0V
Storage temperature .....................................-65
C to +150
C
Ambient temp. with power applied.................-65
C to +125
C
Soldering temperature of leads (10 seconds) ............. +300
C
ESD protection on all pins................................................4 kV
*Notice:
Stresses above those listed under "Maximum ratings" may
cause permanent damage to the device. This is a stress rating only and
functional operation of the device at those or any other conditions
above those indicated in the operational listings of this specification is
not implied. Exposure to maximum rating conditions for extended peri-
ods may affect device reliability.
TABLE 1-1:
PIN FUNCTION TABLE
Name
Function
CS
Chip Select
CLK
Serial Data Clock
DI
Serial Data Input
DO
Serial Data Output
V
SS
Ground
NC
No Connect
V
CC
Power Supply
TABLE 1-2:
DC AND AC ELECTRICAL CHARACTERISTICS
All parameters apply over the
specified operating ranges
unless otherwise noted
Automotive (E)V
CC
= +4.5V to +5.5VTamb = -40
C to +125
C
Parameter
Symbol
Min.
Max.
Units
Conditions
High level input voltage
V
IH
2.0
V
CC
+1
V
(Note 2)
Low level input voltage
V
IL
-0.3
0.8
V
Low level output voltage
V
OL
--
0.4
V
I
OL
= 2.1 mA; V
CC
= 4.5V
High level output voltage
V
OH
2.4
--
V
I
OH
= -400
A; V
CC
= 4.5V
Input leakage current
I
LI
-10
10
A
V
IN
= V
SS
to V
CC
Output leakage current
I
LO
-10
10
A
V
OUT
= V
SS
to V
CC
Pin capacitance
(all inputs/outputs)
C
IN
, C
OUT
--
7
pF
V
IN
/V
OUT
= 0 V (Notes 1 & 2)
Tamb = +25
C, F
CLK
= 1 MHz
Operating current
I
CC
write
--
1.5
mA
I
CC
read
--
1
mA
Standby current
I
CCS
--
1
A
CS = V
SS
Clock frequency
F
CLK
--
2
MHz
Clock high time
T
CKH
250
--
ns
Clock low time
T
CKL
250
--
ns
Chip select setup time
T
CSS
50
--
ns
Relative to CLK
Chip select hold time
T
CSH
0
--
ns
Relative to CLK
Chip select low time
T
CSL
250
--
ns
Data input setup time
T
DIS
100
--
ns
Relative to CLK
Data input hold time
T
DIH
100
--
ns
Relative to CLK
Data output delay time
T
PD
--
400
ns
C
L
= 100 pF
Data output disable time
T
CZ
--
100
ns
C
L
= 100 pF (Note 2)
Status valid time
T
SV
--
500
ns
C
L
= 100 pF
Program cycle time
T
WC
--
2
ms
ERASE/WRITE mode
T
EC
--
6
ms
ERAL mode
T
WL
--
15
ms
WRAL mode
Endurance
--
100K
--
cycles
25
C, V
CC
= 5.0V, Block Mode (Note 3)
Note 1:
This parameter is tested at Tamb = 25
C and F
CLK
= 1 MHz.
2:
This parameter is periodically sampled and not 100% tested.
3:
This application is not tested but guaranteed by characterization. For endurance estimates in a specific
application, please consult the Total Endurance Model which may be obtained on Microchip's BBS or web-
site.
1998 Microchip Technology Inc.
Preliminary
DS21206B-page 4-3
93C56A/B
2.0
PIN DESCRIPTION
2.1
Chip Select (CS)
A high level selects the device. A low level deselects
the device and forces it into standby mode. However, a
programming cycle which is already in progress will be
completed, regardless of the CS input signal. If CS is
brought low during a program cycle, the device will go
into standby mode as soon as the programming cycle
is completed.
CS must be low for 250 ns minimum (T
CSL
) between
consecutive instructions. If CS is low, the internal con-
trol logic is held in a RESET status.
2.2
Serial Clock (CLK)
The Serial Clock is used to synchronize the communi-
cation between a master device and the 93C56A/B.
Opcode, address, and data bits are clocked in on the
positive edge of CLK. Data bits are also clocked out on
the positive edge of CLK.
CLK can be stopped anywhere in the transmission
sequence (at high or low level) and can be continued
anytime with respect to clock high time (T
CKH
) and
clock low time (T
CKL
). This gives the controlling master
freedom in preparing opcode, address, and data.
CLK is a "Don't Care" if CS is low (device deselected).
If CS is high, but the START condition has not been
detected, any number of clock cycles can be received
by the device without changing its status (i.e., waiting
for a START condition).
CLK cycles are not required during the self-timed
WRITE (i.e., auto ERASE/WRITE) cycle.
After detecting a START condition, the specified num-
ber of clock cycles (respectively low to high transitions
of CLK) must be provided. These clock cycles are
required to clock in all required opcode, address, and
data bits before an instruction is executed (Table 2-1
and Table 2-2). CLK and DI then become don't care
inputs waiting for a new START condition to be
detected.
2.3
Data In (DI)
Data In is used to clock in a START bit, opcode,
address, and data synchronously with the CLK input.
2.4
Data Out (DO)
Data Out is used in the READ mode to output data syn-
chronously with the CLK input (T
PD
after the positive
edge of CLK).
This pin also provides READY/BUSY status informa-
tion during ERASE and WRITE cycles. READY/BUSY
status information is available on the DO pin if CS is
brought high after being low for minimum chip select
low time (T
CSL
) and an ERASE or WRITE operation
has been initiated.
The status signal is not available on
DO, if CS is held low during the entire ERASE or
WRITE cycle. In this case, DO is in the HIGH-Z mode.
If status is checked after the ERASE/WRITE cycle, the
data line will be high to indicate the device is ready.
.
Note:
CS must go low between consecutive
instructions.
TABLE 2-1:
INSTRUCTION SET FOR 93C56A
Instruction SB
Opcode
Address
Data In
Data Out
Req. CLK Cycles
ERASE
1
11
X
A7
A6
A5
A4
A3
A2
A1
A0
--
(RDY/BSY)
12
ERAL
1
00
1
0
X
X
X
X
X
X
X
--
(RDY/BSY)
12
EWDS
1
00
0
0
X
X
X
X
X
X
X
--
HIGH-Z
12
EWEN
1
00
1
1
X
X
X
X
X
X
X
--
HIGH-Z
12
READ
1
10
X
A7
A6
A5
A4
A3
A2
A1
A0
--
D7 - D0
20
WRITE
1
01
X
A7
A6
A5
A4
A3
A2
A1
A0
D7 - D0
(RDY/BSY)
20
WRAL
1
00
0
1
X
X
X
X
X
X
X
D7 - D0
(RDY/BSY)
20
TABLE 2-2:
INSTRUCTION SET FOR 93C56B
Instruction SB
Opcode
Address
Data In
Data Out
Req. CLK Cycles
ERASE
1
11
X
A6
A5
A4
A3
A2
A1
A0
--
(RDY/BSY)
11
ERAL
1
00
1
0
X
X
X
X
X
X
--
(RDY/BSY)
11
EWDS
1
00
0
0
X
X
X
X
X
X
--
HIGH-Z
11
EWEN
1
00
1
1
X
X
X
X
X
X
--
HIGH-Z
11
READ
1
10
X
A6
A5
A4
A3
A2
A1
A0
--
D15 - D0
27
WRITE
1
01
X
A6
A5
A4
A3
A2
A1
A0
D15 - D0
(RDY/BSY)
27
WRAL
1
00
0
1
X
X
X
X
X
X
D15 - D0
(RDY/BSY)
27
93C56A/B
DS21206B-page 4
Preliminary
1998 Microchip Technology Inc.
3.0
FUNCTIONAL DESCRIPTION
Instructions, addresses, and write data are clocked into
the DI pin on the rising edge of the clock (CLK). The DO
pin is normally held in a HIGH-Z state except when
reading data from the device, or when checking the
READY/BUSY status during a programming operation.
The READY/BUSY status can be verified during an
ERASE/WRITE operation by polling the DO pin; DO
low indicates that programming is still in progress, while
DO high indicates the device is ready. The DO will enter
the HIGH-Z state on the falling edge of the CS.
3.1
START Condition
The START bit is detected by the device if CS and DI
are both high with respect to the positive edge of CLK
for the first time.
Before a START condition is detected, CS, CLK, and DI
may change in any combination (except to that of a
START condition), without resulting in any device oper-
ation (READ, WRITE, ERASE, EWEN, EWDS, ERAL,
and WRAL). As soon as CS is high, the device is no
longer in the standby mode.
An instruction following a START condition will only be
executed if the required amount of opcode, address
and data bits for any particular instruction is clocked in.
After execution of an instruction (i.e., clock in or out of
the last required address or data bit) CLK and DI
become don't care bits until a new START condition is
detected.
3.2
Data IN (DI) and Data Out (DO)
It is possible to connect the Data In (DI) and Data Out
(DO) pins together. However, with this configuration, if
A0 is a logic-high level, it is possible for a "bus conflict"
to occur during the "dummy zero" that precedes the
READ operation. Under such a condition, the voltage
level seen at DO is undefined and will depend upon the
relative impedances of DO and the signal source driv-
ing A0. The higher the current sourcing capability of A0,
the higher the voltage at the DO pin.
3.3
Data Protection
During power-up, all programming modes of operation
are inhibited until Vcc has reached a level greater than
3.8V. During power-down, the source data protection
circuitry acts to inhibit all programming modes when
Vcc has fallen below 3.8V at nominal conditions.
The ERASE/WRITE Disable (EWDS) and ERASE
WRTE Enable (EWEN) commands give additional pro-
tection against accidentally programming during nor-
mal operation.
After power-up, the device is automatically in the
EWDS mode. Therefore, an EWEN instruction must be
performed before any ERASE or WRITE instruction
can be executed.
FIGURE 3-1:
SYNCHRONOUS DATA TIMING
CS
V
IH
V
IL
V
IH
V
IL
V
IH
V
IL
V
OH
V
OL
V
OH
V
OL
CLK
DI
DO
(READ)
DO
(PROGRAM)
T
CSS
T
DIS
T
CKH
T
CKL
T
DIH
T
PD
T
CSH
T
PD
T
CZ
STATUS VALID
T
SV
T
CZ
Note:
AC Test Conditions: V
IL
= 0.4V, V
IH
= 2.4V.
1998 Microchip Technology Inc.
Preliminary
DS21206B-page 5
93C56A/B
3.4
ERASE
The ERASE instruction forces all data bits of the spec-
ified address to the logical "1" state. This cycle begins
on the rising clock edge of the last address bit.
The DO pin indicates the READY/BUSY status of the
device if CS is brought high after a minimum of 250 ns
low (T
CSL
). DO at logical "0" indicates that program-
ming is still in progress. DO at logical "1" indicates that
the register at the specified address has been erased
and the device is ready for another instruction.
3.5
Erase All (ERAL)
The ERAL instruction will erase the entire memory
array to the logical "1" state. The ERAL cycle is identical
to the ERASE cycle, except for the different opcode.
The ERAL cycle is completely self-timed and com-
mences at the rising clock edge of the last address bit.
Clocking of the CLK pin is not necessary after the
device has entered the ERAL cycle.
The DO pin indicates the READY/BUSY status of the
device, if CS is brought high after a minimum of 250 ns
low (T
CSL
) and before the entire ERAL cycle is com-
plete.
FIGURE 3-2:
ERASE TIMING
FIGURE 3-3:
ERAL TIMING
CS
CLK
DI
DO
T
CSL
CHECK STATUS
1
1
1
A
N
A
N
-1
A
N
-2
A0
T
SV
T
CZ
BUSY
READY
HIGH-Z
T
WC
HIGH-Z
CS
CLK
DI
DO
T
CSL
CHECK STATUS
1
0
0
1
0
X
X
T
SV
T
CZ
BUSY
READY
HIGH-Z
T
EC
HIGH-Z
PDF 
ZIP