Features
•Fast Read Access Time – 45 ns
•Low-Power CMOS Operation
– 100 µA Max Standby
– 20 mA Max Active at 5 MHz
•JEDEC Standard Packages
– 28-lead PDIP
– 32-lead PLCC
– 28-lead TSOP and SOIC
•5V ± 10% Supply
•High Reliability CMOS Technology
– 2,000V ESD Protection
– 200 mA Latchup Immunity
•Rapid Programming Algorithm – 100 µs/Byte (Typical)
•CMOS and TTL Compatible Inputs and Outputs
•Integrated Product Identification Code
•Industrial and Automotive Temperature Ranges
•Green (Pb/Halide-free) Packaging Option
1. Description
The AT27C256R is a low-power, high-performance 262,144-bit one-time programma-
ble read-only memory (OTP EPROM) organized 32K by 8 bits. It requires only one 5V
power supply in normal read mode operation. Any byte can be accessed in less than
45 ns, eliminating the need for speed reducing WAIT states on high-performance
microprocessor systems.
Atmel’s scaled CMOS technology provides low-active power consumption, and fast
programming. Power consumption is typically only 8 mA in Active Mode and less than
10 µA in Standby.
The AT27C256R is available in a choice of industry-standard JEDEC-approved one
time programmable (OTP) plastic DIP, PLCC, SOIC, and TSOP packages. All devices
feature two-line control (CE, OE) to give designers the flexibility to prevent bus
contention.
With 32K byte storage capability, the AT27C256R allows firmware to be stored reli-
ably and to be accessed by the system without the delays of mass storage media.
Atmel’s AT27C256R has additional features to ensure high quality and efficient pro-
duction use. The Rapid Programming Algorithm reduces the time required to program
the part and guarantees reliable programming. Programming time is typically only
100 µs/byte. The Integrated Product Identification Code electronically identifies the
device and manufacturer. This feature is used by industry-standard programming
equipment to select the proper programming algorithms and voltages.
256K (32K x 8)
OTP EPROM
AT27C256R
0014M–EPROM–12/07
2
0014M–EPROM–12/07
AT27C256R
2.1 28-lead PDIP/SOIC Top View
2.2 32-lead PLCC Top View
Note: PLCC Package Pins 1 and 17 are Don’t Connect.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VPP
A12
A7
A6
A5
A4
A3
A2
A1
A0
O0
O1
O2
GND
VCC
A14
A13
A8
A9
A11
OE
A10
CE
O7
O6
O5
O4
O3
5
6
7
8
9
10
11
12
13
29
28
27
26
25
24
23
22
21
A6
A5
A4
A3
A2
A1
A0
NC
O0
A8
A9
A11
NC
OE
A10
CE
O7
O6
4
3
2
1
32
31
30
14
15
16
17
18
19
20
O1
O2
GND
NC
O3
O4
O5
A7
A12
VPP
NC
VCC
A14
A13
2.3 28-lead TSOP Top View – Type 1
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VPP
A12
A7
A6
A5
A4
A3
A10
CE
O7
O6
O5
O4
O3
GND
O2
O1
O0
A0
A1
A2
OE
A11
A9
A8
A13
A14
VCC
1
2
3
4
5
6
7
2. Pin Configurations
Pin Name Function
A0 - A14 Addresses
O0 - O7 Outputs
CE Chip Enable
OE Output Enable
NC No Connect
3
0014M–EPROM–12/07
AT27C256R
3. System Considerations
Switching between active and standby conditions via the Chip Enable pin may produce tran-
sient voltage excursions. Unless accommodated by the system design, these transients may
exceed datasheet limits, resulting in device non-conformance. At a minimum, a 0.1 µF high
frequency, low inherent inductance, ceramic capacitor should be utilized for each device. This
capacitor should be connected between the VCC and Ground terminals of the device, as close
to the device as possible. Additionally, to stabilize the supply voltage level on printed circuit
boards with large EPROM arrays, a 4.7 µF bulk electrolytic capacitor should be utilized, again
connected between the VCC and Ground terminals. This capacitor should be positioned as
close as possible to the point where the power supply is connected to the array.
4. Block Diagram
Note: 1. Minimum voltage is -0.6V DC which may undershoot to -2.0V for pulses of less than 20 ns. Maximum output pin voltage is
VCC + 0.75V dc which may overshoot to +7.0 volts for pulses of less than 20 ns.
5. Absolute Maximum Ratings*
Temperature Under Bias................................ -55°C to +125°C *NOTICE: Stresses beyond those listed under “Absolute Maxi-
mum Ratings” may cause permanent damage to
the device. This is a stress rating only and func-
tional operation of the device at these or any other
conditions beyond those indicated in the opera-
tional sections of this specification is not implied.
Exposure to absolute maximum rating conditions
for extended periods may affect device reliability.
Storage Temperature ..................................... -65°C to +150°C
Voltage on Any Pin with
Respect to Ground .........................................-2.0V to +7.0V(1)
Voltage on A9 with
Respect to Ground ......................................-2.0V to +14.0V(1)
VPP Supply Voltage with
Respect to Ground .......................................-2.0V to +14.0V(1)
4
0014M–EPROM–12/07
AT27C256R
Notes: 1. X can be VIL or VIH.
2. Refer to Programming Characteristics.
3. VH = 12.0 ± 0.5V.
4. Two identifier bytes may be selected. All Ai inputs are held low (VIL), except A9 which is set to VH and A0 which is toggled
low (VIL) to select the Manufacturer’s Identification byte and high (VIH) to select the Device Code byte.
Notes: 1. VCC must be applied simultaneously with or before VPP
, and removed simultaneously with or after VPP
..
2. VPP may be connected directly to VCC, except during programming. The supply current would then be the sum of ICC and IPP
.
6. Operating Modes
Mode/Pin CE OE Ai VPP Outputs
Read VIL VIL Ai VCC DOUT
Output Disable VIL VIH X
(1) VCC High Z
Standby VIH X
(1) X
(1) VCC High Z
Rapid Program(2) VIL VIH Ai VPP DIN
PGM Verify(2) X
(1) VIL Ai VPP DOUT
Optional PGM Verify(2) VIL VIL Ai VCC DOUT
PGM Inhibit(2) VIH VIH X(1) VPP High Z
Product Identification(4) VIL VIL
A9 = VH(3)
A0 = VIH or VIL
A1 - A14 = VIL
VCC Identification Code
7. DC and AC Operating Conditions for Read Operation
AT27C256R
-45 -70
Operating Temp. (Case) Ind. -40°C - 85°C-40°C - 85°C
Auto. -40°C - 125°C
VCC Supply 5V ± 10% 5V ± 10%
8. DC and Operating Characteristics for Read Operation
Symbol Parameter Condition Min Max Units
ILI Input Load Current VIN = 0V to VCC
Ind. ±1 µA
Auto. ±5 µA
ILO Output Leakage Current VOUT = 0V to VCC
Ind. ±5 µA
Auto. ±10 µA
IPP1(2) VPP(1) Read/Standby Current VPP = VCC 10 µA
ISB VCC(1) Standby Current ISB1 (CMOS), CE = VCC ± 0.3V 100 µA
ISB2 (TTL), CE = 2.0 to VCC + 0.5V 1 mA
ICC VCC Active Current f = 5 MHz, IOUT = 0 mA, E = VIL 20 mA
VIL Input Low Voltage -0.6 0.8 V
VIH Input High Voltage 2.0 VCC + 0.5 V
VOL Output Low Voltage IOL = 2.1 mA 0.4 V
VOH Output High Voltage IOH = -400 µA 2.4 V
5
0014M–EPROM–12/07
AT27C256R
.
Note: 1. See AC Waveforms for Read Operation.
10. AC Waveforms for Read Operation(1)
Notes: 1. Timing measurement reference level is 1.5V for -45 devices. Input AC drive levels are VIL = 0.0V and VIH = 3.0V. Timing mea-
surement reference levels for all other speed grades are VOL = 0.8V and VOH = 2.0V. Input AC drive levels are VIL = 0.45V
and VIH = 2.4V.
2. OE may be delayed up to tCE - tOE after the falling edge of CE without impact on tCE.
3. OE may be delayed up to tACC - tOE after the address is valid without impact on tACC.
4. This parameter is only sampled and is not 100% tested.
5. Output float is defined as the point when data is no longer driven.
9. AC Characteristics for Read Operation
Symbol Parameter Condition
AT27C256R
Units
-45 -70
Min Max Min Max
tACC(1) Address to Output Delay CE = OE = VIL 45 70 ns
tCE(1) CE to Output Delay OE = VIL 45 70 ns
tOE(1) OE to Output Delay CE = VIL 20 30 ns
tDF(1) OE or CE High to Output
Float, Whichever Occurred First 20 25 ns
tOH
Output Hold from Address, CE or OE,
Whichever Occurred First 77 ns
6
0014M–EPROM–12/07
AT27C256R
11. Input Test Waveforms and Measurement Levels
12. Output Test Load
Note: 1. CL = 100 pF including jig capacitance, except for the -45 devices, where CL = 30 pF.
Note: 1. Typical values for nominal supply voltage. This parameter is only sampled and is not 100% tested.
tR, tF < 5 ns (10% to 90%)
For -45 devices only:
tR, tF < 20 ns (10% to 90%)
For -70 devices:
13. Pin Capacitance
f = 1 MHz, T = 25°C(1)
Symbol Typ Max Units Conditions
CIN 46pFV
IN = 0V
COUT 812pFV
OUT = 0V
7
0014M–EPROM–12/07
AT27C256R
14. Programming Waveforms(1)
Notes: 1. The Input Timing Reference is 0.8V for VIL and 2.0V for VIH.
2. tOE and tDFP are characteristics of the device but must be accommodated by the programmer.
3. When programming the AT27C256R a 0.1 µF capacitor is required across VPP and ground to suppress spurious voltage
transients.
15. DC Programming Characteristics
TA = 25 ± 5°C, VCC = 6.5 ± 0.25V, VPP = 13.0 ± 0.25V
Symbol Parameter Test Conditions
Limits
UnitsMin Max
ILI Input Load Current VIN = VIL,VIH ±10 µA
VIL Input Low Level -0.6 0.8 V
VIH Input High Level 2.0 VCC + 1 V
VOL Output Low Volt IOL = 2.1 mA 0.4 V
VOH Output High Volt IOH = -400 µA 2.4 V
ICC2 VCC Supply Current (Program and Verify) 25 mA
IPP2 VPP Current CE = VIL 25 mA
VID A9 Product Identification Voltage 11.5 12.5 V
8
0014M–EPROM–12/07
AT27C256R
Notes: 1. VCC must be applied simultaneously or before VPP and removed simultaneously or after VPP
.
2. This parameter is only sampled and is not 100% tested. Output Float is defined as the point where data is no longer
driven – see timing diagram.
3. Program Pulse width tolerance is 100 µsec ± 5%.
16. AC Programming Characteristics
TA = 25 ± 5°C, VCC = 6.5 ± 0.25V, VPP = 13.0 ± 0.25V
Symbol Parameter Test Conditions(1)
Limits
UnitsMin Max
tAS Address Setup Time
Input Rise and Fall Times
(10% to 90%) 20 ns
Input Pulse Levels
0.45V to 2.4V
Input Timing Reference Level
0.8V to 2.0V
Output Timing Reference Level
0.8V to 2.0V
2µs
tOES OE Setup Time 2 µs
tDS Data Setup Time 2 µs
tAH Address Hold Time 0 µs
tDH Data Hold Time 2 µs
tDFP OE High to Output Float Delay(2) 0130ns
tVPS VPP Setup Time 2 µs
tVCS VCC Setup Time 2 µs
tPW CE Program Pulse Width(3) 95 105 µs
tOE Data Valid from OE(2) 150 ns
tPRT VPP Pulse Rise Time During Programming 50 ns
17. Atmel’s AT27C256R Integrated Product Identification Code
Codes
Pins Hex
DataA0 O7 O6 O5 O4 O3 O2 O1 O0
Manufacturer 000011110 1E
Device Type 110001100 8C
9
0014M–EPROM–12/07
AT27C256R
18. Rapid Programming Algorithm
A 100 µs CE pulse width is used to program. The address is set to the first location. VCC is
raised to 6.5V and VPP is raised to 13.0V. Each address is first programmed with one 100 µs
CE pulse without verification. Then a verification/reprogramming loop is executed for each
address. In the event a byte fails to pass verification, up to 10 successive 100 µs pulses are
applied with a verification after each pulse. If the byte fails to verify after 10 pulses have been
applied, the part is considered failed. After the byte verifies properly, the next address is
selected until all have been checked. VPP is then lowered to 5.0V and VCC to 5.0V. All bytes
are read again and compared with the original data to determine if the device passes or fails.
10
0014M–EPROM–12/07
AT27C256R
19. Ordering Information
Note: 1. The 28-pin SOIC package is not recommended for new designs.
19.1 Standard Package
tACC
(ns)
ICC (mA)
Ordering Code Package Operation RangeActive Standby
45 20 0.1 AT27C256R-45JI
AT27C256R-45PI
AT27C256R-45RI
AT27C256R-45TI
32J
28P6
28R(1)
28T
Industrial
(-40°C to 85°C)
70 20 0.1 AT27C256R-70JI
AT27C256R-70PI
AT27C256R-70RI
AT27C256R-70TI
32J
28P6
28R(1)
28T
Industrial
(-40°C to 85°C)
20 0.1 AT27C256R-70JA
AT27C256R-70PA
AT27C256R-70RA
32J
28P6
28R(1)
Automotive
(-40°C to 125°C)
Note: Not recommended for new designs. Use Green package option.
19.2 Green Package (Pb/Halide-free)
tACC
(ns)
ICC (mA)
Ordering Code Package Operation RangeActive Standby
45 20 0.1 AT27C256R-45JU
AT27C256R-45PU
AT27C256R-45RU
AT27C256R-45TU
32J
28P6
28R(1)
28T
Industrial
(-40°C to 85°C)
70 20 0.1 AT27C256R-70JU
AT27C256R-70PU
AT27C256R-70RU
AT27C256R-70TU
32J
28P6
28R(1)
28T
Industrial
(-40°C to 85°C)
Package Type
32J 32-lead, Plastic J-Leaded Chip Carrier (PLCC)
28P6 28-lead, 0.600" Wide, Plastic Dual Inline Package (PDIP)
28R 28-lead, 0.330" Wide, Plastic Gull Wing Small Outline (SOIC)
28T 28-lead, Thin Small Outline Package (TSOP)
11
0014M–EPROM–12/07
AT27C256R
20. Packaging Information
20.1 32J – PLCC
DRAWING NO. REV.
2325 Orchard Parkway
San Jose, CA 95131
R
TITLE
32J, 32-lead, Plastic J-leaded Chip Carrier (PLCC) B
32J
10/04/01
1.14(0.045) X 45˚ PIN NO. 1
IDENTIFIER
1.14(0.045) X 45˚
0.51(0.020)MAX
0.318(0.0125)
0.191(0.0075)
A2
45˚ MAX (3X)
A
A1
B1 E2
B
e
E1 E
D1
D
D2
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
Notes: 1. This package conforms to JEDEC reference MS-016, Variation AE.
2. Dimensions D1 and E1 do not include mold protrusion.
Allowable protrusion is .010"(0.254 mm) per side. Dimension D1
and E1 include mold mismatch and are measured at the extreme
material condition at the upper or lower parting line.
3. Lead coplanarity is 0.004" (0.102 mm) maximum.
A 3.175 – 3.556
A1 1.524 – 2.413
A2 0.381 – –
D 12.319 – 12.573
D1 11.354 – 11.506 Note 2
D2 9.906 – 10.922
E 14.859 – 15.113
E1 13.894 – 14.046 Note 2
E2 12.471 – 13.487
B 0.660 – 0.813
B1 0.330 – 0.533
e 1.270 TYP
12
0014M–EPROM–12/07
AT27C256R
20.2 28P6 – PDIP
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
28P6, 28-lead (0.600"/15.24 mm Wide) Plastic Dual
Inline Package (PDIP) B
28P6
09/28/01
PIN
1
E1
A1
B
REF
E
B1
C
L
SEATING PLANE
A
0º ~ 15º
D
e
eB
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
A – – 4.826
A1 0.381 – –
D 36.703 – 37.338 Note 2
E 15.240 – 15.875
E1 13.462 – 13.970 Note 2
B 0.356 – 0.559
B1 1.041 – 1.651
L 3.048 – 3.556
C 0.203 – 0.381
eB 15.494 – 17.526
e 2.540 TYP
Notes: 1. This package conforms to JEDEC reference MS-011, Variation AB.
2. Dimensions D and E1 do not include mold Flash or Protrusion.
Mold Flash or Protrusion shall not exceed 0.25 mm (0.010").
13
0014M–EPROM–12/07
AT27C256R
20.3 28R – SOIC
A 2.39 – 2.79
A1 0.050 – 0.356
D 18.00 – 18.50 Note 1
E 11.70 – 12.50
E1 8.59 – 8.79 Note 1
B 0.356 – 0.508
C 0.203 – 0.305
L 0.94 – 1.27
e 1.27 TYP
PIN 1
0º ~ 8º
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
28R, 28-lead, 0.330" Body Width,
Plastic Gull Wing Small Outline (SOIC) C
28R
5/18/2004
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
A
E
C
A1
E1
e
D
L
B
Note: 1. Dimensions D and E1 do not include mold Flash
or protrusion. Mold Flash or protrusion shall not exceed
0.25 mm (0.010").
14
0014M–EPROM–12/07
AT27C256R
20.4 28T – TSOP
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
28T, 28-lead (8 x 13.4 mm) Plastic Thin Small Outline
Package, Type I (TSOP) C
28T
12/06/02
PIN 1 0º ~ 5º
D1 D
Pin 1 Identifier Area
b
e
EA
A1
A2
c
L
GAGE PLANE
SEATING PLANE
L1
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
Notes: 1. This package conforms to JEDEC reference MO-183.
2. Dimensions D1 and E do not include mold protrusion. Allowable
protrusion on E is 0.15 mm per side and on D1 is 0.25 mm per side.
3. Lead coplanarity is 0.10 mm maximum.
A – – 1.20
A1 0.05 – 0.15
A2 0.90 1.00 1.05
D 13.20 13.40 13.60
D1 11.70 11.80 11.90 Note 2
E 7.90 8.00 8.10 Note 2
L 0.50 0.60 0.70
L1 0.25 BASIC
b 0.17 0.22 0.27
c 0.10 – 0.21
e 0.55 BASIC
0014M–EPROM–12/07
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Atmel Corporation
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USA
Tel: 1(408) 441-0311
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