tionality with an implementation based on the FIPS
180-3-specified Secure Hash Algorithm (SHA-256). A
2Kb user-programmable EEPROM array provides non-
volatile storage of application data and additional pro-
tected memory holds a read-protected secret for SHA-
256 operations and settings for user memory control.
Each device has its own guaranteed unique 64-bit
ROM identification number (ROM ID) that is factory pro-
grammed into the chip. This unique ROM ID is used as
a fundamental input parameter for cryptographic opera-
tions and also serves as an electronic serial number
within the application. A bidirectional security model
enables two-way authentication between a host system
and slave-embedded DS28E22. Slave-to-host authenti-
cation is used by a host system to securely validate that
an attached or embedded DS28E22 is authentic. Host-
to-slave authentication is used to protect DS28E22 user
memory from being modified by a nonauthentic host. The
SHA-256 message authentication code (MAC), which the
DS28E22 generates, is computed from data in the user
memory, an on-chip secret, a host random challenge,
and the 64-bit ROM ID. The DS28E22 communicates
over the single-contact 1-Wire
M
bus at overdrive speed.
The communication follows the 1-Wire protocol with the
ROM ID acting as node address in the case of a multiple-
device 1-Wire network.
EVALUATION KIT AVAILABLE
Features
S
Symmetric Key-Based Bidirectional Secure
Authentication Model Based on SHA-256
S
Dedicated Hardware-Accelerated SHA Engine for
Generating SHA-256 MACs
S
Strong Authentication with a High Bit Count, User-
Programmable Secret, and Input Challenge
S
2048 Bits of User EEPROM Partitioned Into 8
Pages of 256 Bits
S
User-Programmable and Irreversible EEPROM
Protection Modes Including Authentication, Write
and Read Protect, and OTP/EPROM Emulation
S
Unique, Factory-Programmed 64-Bit Identification
Number
S
Single-Contact 1-Wire Interface Communicates
with Host at Up to 76.9kbps
S
Operating Range: 3.3V
±10%,
-40NC to +85NC
S
Low-Power 5µA (typ) Standby
S
±8kV
Human Body Model ESD Protection (typ)
S
6-Pin TDFN, 6-Lead TSOC Packages
Typical Application Circuit
3.3V
R
P
(I
2
C PORT)
µC
SLPZ
SDA
SCL
V
CC
R
P
= 1.1kΩ
MAXIMUM I
2
C BUS CAPACITANCE 320pF
Applications
Authentication of Network-Attached Appliances
Printer Cartridge ID/Authentication
Reference Design License Management
System Intellectual Property Protection
Sensor/Accessory Authentication and Calibration
Secure Feature Setting for Configurable Systems
Key Generation and Exchange for Cryptographic
Systems
Ordering Information
appears at end of data sheet.
1-Wire is a registered trademark of Maxim Integrated Products, Inc.
DS2465
1-Wire LINE
IO
DS28E22
For related parts and recommended products to use with this part, refer to:
www.maximintegrated.com/DS28E22.related
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
219-0020; Rev 0; 9/12
ABRIDGED DATA SHEET
DS28E22
1-Wire SHA-256 Secure Authenticator
with 2Kb User EEPROM
ABSOLUTE MAXIMUM RATINGS
IO Voltage Range to GND...................................... -0.5V to 4.0V
IO Sink Current ...................................................................20mA
Operating Temperature Range ......................... -40NC to +85NC
Junction Temperature .....................................................+150NC
Storage Temperature Range............................ -55NC to +125NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(T
A
= -40NC to +85NC, unless otherwise noted.) (Note 1)
PARAMETER
IO PIN: GENERAL DATA
1-Wire Pullup Voltage
1-Wire Pullup Resistance
Input Capacitance
Input Load Current
High-to-Low Switching Threshold
Input Low Voltage
Low-to-High Switching Threshold
Switching Hysteresis
Output Low Voltage
Recovery Time
Time-Slot Duration
Reset Low Time
Reset High Time
Presence-Detect Sample Time
IO PIN: 1-Wire WRITE
Write-Zero Low Time
Write-One Low Time
IO PIN: 1-Wire READ
Read Low Time
Read Sample Time
EEPROM
Programming Current
Programming Time for a 32-Bit
Segment
Write/Erase Cycling Endurance
Data Retention
Maxim Integrated
SYMBOL
V
PUP
R
PUP
C
IO
I
L
V
TL
V
IL
V
TH
V
HY
V
OL
t
REC
t
SLOT
t
RSTL
t
RSTH
t
MSP
t
W0L
t
W1L
t
RL
t
MSR
I
PROG
t
PROG
N
CY
t
DR
(Note 2)
CONDITIONS
MIN
2.97
300
TYP
MAX
3.63
1500
UNITS
V
I
pF
FA
V
V
PUP
= 3.3V
Q
10% (Note 3)
(Notes 4, 5)
IO pin at V
PUP
(Notes 6, 7)
(Notes 2, 8)
(Notes 6, 9)
(Notes 6, 10)
I
OL
= 4mA (Note 11)
R
PUP
= 1500I (Notes 2, 12)
(Notes 2, 13)
(Note 2)
(Note 14)
(Notes 2, 15)
(Notes 2, 16)
(Notes 2, 16)
(Notes 2, 17)
(Notes 2, 17)
V
PUP
= 3.63V (Notes 5, 18)
(Note 19)
T
A
= +85NC (Notes 20, 21)
T
A
= +125NC (storage) (Notes 22, 23, 24)
1500
5
0.65 x
V
PUP
0.3
0.75 x
V
PUP
0.3
0.4
5
13
48
48
8
8
1
1
t
RL
+
d
10
16
2
2-
d
2
1
10
100k
10
80
19.5
V
V
V
V
Fs
Fs
Fs
Fs
Fs
Fs
Fs
Fs
Fs
mA
ms
—
Years
2
IO PIN: 1-Wire RESET, PRESENCE-DETECT CYCLE
ABRIDGED DATA SHEET
DS28E22
1-Wire SHA-256 Secure Authenticator
with 2Kb User EEPROM
ELECTRICAL CHARACTERISTICS (continued)
(T
A
= -40NC to +85NC, unless otherwise noted.) (Note 1)
PARAMETER
SHA-256 ENGINE
Computation Current
Computation Time
I
CSHA
t
CSHA
Refer to the full data sheet.
mA
ms
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Note 1:
Limits are 100% production tested at T
A
= +25°C and/or T
A
= +85°C. Limits over the operating temperature range and
relevant supply voltage range are guaranteed by design and characterization. Typical values are not guaranteed.
Note 2:
System requirement.
Note 3:
Maximum allowable pullup resistance is a function of the number of 1-Wire devices in the system and 1-Wire recovery
times. The specified value here applies to systems with only one device and with the minimum 1-Wire recovery times.
Note 4:
Typical value represents the internal parasite capacitance when V
PUP
is first applied. Once the parasite capacitance is
charged, it does not affect normal communication.
Note 5:
Guaranteed by design and/or characterization only; not production tested.
Note 6:
V
TL
, V
TH
, and V
HY
are a function of the internal supply voltage, which is a function of V
PUP
, R
PUP
, 1-Wire timing, and
capacitive loading on IO. Lower V
PUP
, higher R
PUP
, shorter t
REC
, and heavier capacitive loading all lead to lower values
of V
TL
, V
TH
, and V
HY
.
Note 7:
Voltage below which, during a falling edge on IO, a logic-zero is detected.
Note 8:
The voltage on IO must be less than or equal to V
ILMAX
at all times when the master is driving IO to a logic-zero level.
Note 9:
Voltage above which, during a rising edge on IO, a logic-one is detected.
Note 10:
After V
TH
is crossed during a rising edge on IO, the voltage on IO must drop by at least V
HY
to be detected as logic-zero.
Note 11:
The I-V characteristic is linear for voltages less than 1V.
Note 12:
Applies to a single device attached to a 1-Wire line.
Note 13:
Defines maximum possible bit rate. Equal to 1/(t
W0LMIN
+ t
RECMIN
).
Note 14:
An additional reset or communication sequence cannot begin until the reset high time has expired.
Note 15:
Interval after t
RSTL
during which a bus master can read a logic 0 on IO if there is a DS28E22 present. The power-up pres-
ence detect pulse could be outside this interval, but will be complete within 2ms after power-up.
Note 16:
ε
in
Figure 11
represents the time required for the pullup circuitry to pull the voltage on IO up from V
IL
to V
TH
. The actual
maximum duration for the master to pull the line low is t
W1LMAX
+ t
F
-
ε
and t
W0LMAX
+ t
F
-
ε,
respectively.
Note 17:
d
in
Figure 11
represents the time required for the pullup circuitry to pull the voltage on IO up from V
IL
to the input-high
threshold of the bus master. The actual maximum duration for the master to pull the line low is t
RLMAX
+ t
F
.
Note 18:
Current drawn from IO during the EEPROM programming interval or SHA-256 computation. The pullup circuit on IO dur-
ing the programming and computation interval should be such that the voltage at IO is greater than or equal to V
PUPMIN
.
A low-impedence bypass of R
PUP
activated during programming and computation is the recommended way to meet this
requirement.
Note 19: Refer to the full data sheet.
20:
Write-cycle endurance is tested in compliance with JESD47G.
21:
Not 100% production tested; guaranteed by reliability monitor sampling.
22:
Data retention is tested in compliance with JESD47G.
23:
Guaranteed by 100% production test at elevated temperature for a shorter time; equivalence of this production test to the
data sheet limit at operating temperature range is established by reliability testing.
Note 24:
EEPROM writes can become nonfunctional after the data retention time is exceeded. Long-term storage at elevated tem-
peratures is not recommended.
Note 25: Refer to the full data sheet.
Note
Note
Note
Note
Maxim Integrated
3
ABRIDGED DATA SHEET
DS28E22
1-Wire SHA-256 Secure Authenticator
with 2Kb User EEPROM
Pin Configuration
TOP VIEW
TOP VIEW
DS28E22
6 N.C.
DS28E22
5
4
N.C.
N.C.
N.C.
IO
GND
1
2
3
+
GND
IO
N.C.
1
2
3
+
28E22
ymrrF
6
5
4
N.C.
N.C.
N.C.
TSOC
EP
TDFN
(3mm × 3mm)
Pin Description
PIN
TSOC
1
2
3, 4, 5, 6
—
TDFN-EP
3
2
1, 4, 5, 6
—
NAME
GND
IO
N.C.
EP
Ground Reference
1-Wire Bus Interface. Open-drain signal that requires an external pullup resistor.
Not Connected
Exposed Pad (TDFN only). Solder evenly to the board’s ground plane for proper
operation. Refer to Application Note 3273:
Exposed Pads: A Brief Introduction
for
additional information.
FUNCTION
Maxim Integrated
4
ABRIDGED DATA SHEET
DS28E22
1-Wire SHA-256 Secure Authenticator
with 2Kb User EEPROM
Note to readers:
This document is an abridged version of the full data sheet. Additional device information is
available only in the full version of the data sheet. To request the full data sheet, go to
www.maximintegrated.
com/DS28E22
and click on
Request Full Data Sheet.
Ordering Information
PART
DS28E22P+*
DS28E22P+T*
DS28E22Q+T
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
6 TSOC
6 TSOC (4k pcs)
6 TDFN-EP** (2.5k pcs)
Package Information
For the latest package outline information and land patterns (foot-
prints), go to
www.maximintegrated.com/packages.
Note that
a “+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but the
drawing pertains to the package regardless of RoHS status.
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