HT27LC010
Functional Description
Operation Mode
All the operation modes are shown in the table following.
Mode
CE
VIL
OE
VIL
VIH
X
PGM
X (2)
X
A0
X
A1
X
A9
VPP
Output
Dout
Read
X
VCC
VCC
VCC
VCC
VPP
VPP
VPP
VCC
VCC
Output Disable
Standby (TTL)
Standby (CMOS)
Program
VIL
X
X
X
High Z
High Z
High Z
DIN
VIH
X
X
X
X
X
X
X
X
X
V
CC± 0.3V
VIL
VIH
VIL
X
VIL
VIH
X
X
X
X
Program Verify
Product Inhibit
Manufacturer Code (3)
Device Code (3)
VIL
X
X
X
DOUT
High Z
1C
VIH
X
X
X
VIL
VIL
VIL
X
VIL
VIH
VIH
VIH
VH (1)
VH (1)
VIL
X
01
Notes:
(1) ²VH² 12.0V ± 0.5V
(2) ²X² Either VIH or VIL
(3) For Manufacturer Code and Device Code, A1=VIH, When A1=VIL, both codes will read 7F
Programming of the HT27LC010
program pulse applied to an HT27LC010 CE input with
Vpp=12.5±0.2V, PGM LOW, and OE HIGH will program
that HT27LC010. A high-level CE input inhibits the
HT27LC010 from being programmed.
When the HT27LC010 is delivered, the chip has all
1024K bits in the ²ONE², or HIGH state. ²ZEROs² are
loaded into the HT27LC010 through programming.
The programming mode is entered when 12.5±0.2V is
applied to the VPP pin, OE is at VIH, and CE and PGM are
VIL. For programming, the data to be programmed is ap-
plied with 8 bits in parallel to the data pins.
Program Verify Mode
Verification should be performed on the programmed
bits to determine whether they were correctly pro-
grammed. The verification should be performed with OE
and CE at VIL, PGM at VIH, and VPP at its programming
voltage.
The programming flowchart in Figure 3 shows the fast
interactive programming algorithm. The interactive al-
gorithm reduces programming time by using 30ms to
105ms programming pulses and giving each address
only as many pulses as is necessary in order to reliably
program the data. After each pulse is applied to a given
address, the data in that address is verified. If the data is
not verified, additional pulses are given until it is verified
or until the maximum number of pulses is reached while
sequencing through each address of the HT27LC010.
This process is repeated while sequencing through
each address of the HT27LC010. This part of the pro-
gramming algorithm is done at VCC=6.0V to assure that
each EPROM bit is programmed to a sufficiently high
threshold voltage. This ensures that all bits have suffi-
cient margin. After the final address is completed, the
entire EPROM memory is read at VCC=VPP=3.3±0.3V to
verify the entire memory.
Auto Product Identification
The Auto Product Identification mode allows the reading
out of a binary code from an EPROM that will identify its
manufacturer and the type. This mode is intended for
programming to automatically match the device to be
programmed with its corresponding programming algo-
rithm. This mode is functional in the 25°C±5°C ambient
temperature range that is required when programming
the HT27LC010.
To activate this mode, the programming equipment must
force 12.0±0.5V on the address line A9 of the
HT27LC010. Two identifier bytes may then be se-
quenced from the device outputs by toggling address
line A0 from VIL to VIH, when A1=VIH. All other address
lines must be held at VIH during Auto Product Identifica-
tion mode.
Program Inhibit Mode
Byte 0 (A0=VIL) represents the manufacturer code, and
byte 1 (A0=VIH), the device code. For HT27LC010,
these two identifier bytes are given in the Mode Select
Table. All identifiers for the manufacturer and device
Programming of multiple HT27LC010 in parallel with dif-
ferent data is also easily accomplished by using the Pro-
gram Inhibit Mode. Except for CE, all like inputs of the
parallel HT27LC010 may be common. A TTL low-level
Rev. 1.30
5
December 8, 2003