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DS28EL25
DeepCover Secure Authenticator
with 1-Wire SHA-256 with 4Kb User EEPROM
General Description
DeepCover® embedded security solutions cloak sensitive
data under multiple layers of advanced physical security
to provide the industry’s most secure key storage possible. The Deepcover Secure Authenticator (DS28EL25)
combines crypto-strong, bidirectional, secure challengeand-response authentication functionality with an implementation based on the FIPS 180-3-specified Secure
Hash Algorithm (SHA-256). A 4Kb user-programmable
EEPROM array provides nonvolatile storage of application data and additional protected memory holds a readprotected 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 programmed into the chip. This unique ROM ID is
used as a fundamental input parameter for cryptographic
operations 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 DS28EL25. Slave-to-host authentication is used by a host system to securely validate that
an attached or embedded DS28EL25 is authentic. Hostto-slave authentication is used to protect DS28EL25 user
memory from being modified by a nonauthentic host. The
SHA-256 message authentication code (MAC), which the
DS28EL25 generates, is computed from data in the user
memory, an on-chip secret, a host random challenge, and
the 64-bit ROM ID. The DS28EL25 communicates over
the single-contact 1-Wire® 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.
Features
● Symmetric Key-Based Bidirectional Secure
Authentication Model Based on SHA-256
● Dedicated Hardware-Accelerated SHA Engine for
Generating SHA-256 MACs
● Strong Authentication with a High Bit Count, UserProgrammable Secret, and Input Challenge
● 4096 Bits of User EEPROM Partitioned Into 16
Pages of 256 Bits
● User-Programmable and Irreversible EEPROM
Protection Modes Including Authentication, Write and
Read Protect, and OTP/EPROM Emulation
● Unique, Factory-Programmed 64-Bit Identification
Number
● Single-Contact 1-Wire Interface Communicates with
Host at Up to 76.9kbps
● Operating Range: 1.8V ±5%, -40°C to +85°C
● Low-Power 5µA (typ) Standby
● ±8kV Human Body Model ESD Protection (typ)
● 6-Pin TDFN Package
Typical Application Circuit
1.8V
RP
(I2C PORT)
SLPZ
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
RP = 820Ω
MAXIMUM I2C BUS CAPACITANCE 400pF
VCC
DS24L65
µC
Applications
●
●
●
●
●
●
●
SDA
SCL
IO
1-Wire LINE
DS28EL25
Ordering Information appears at end of data sheet.
1-Wire and DeepCover are registered trademarks of Maxim Integrated Products, Inc.
219-0022; Rev 1; 6/21
© 2021 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners.
One Analog Way, Wilmington, MA 01887 U.S.A.
|
Tel: 781.329.4700
|
© 2021 Analog Devices, Inc. All rights reserved.
ABRIDGED DATA SHEET
DS28EL25
DeepCover Secure Authenticator
with 1-Wire SHA-256 with 4Kb User EEPROM
ABSOLUTE MAXIMUM RATINGS
IO Voltage Range to GND.......................................-0.5V to 4.0V
IO Sink Current...................................................................20mA
Operating Temperature Range ........................... -40°C to +85°C
Junction Temperature.......................................................+150°C
Storage Temperature Range............................. -55°C to +125°C
Lead Temperature (soldering, 10s).................................. +300°C
Soldering Temperature (reflow)........................................+260°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation
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
(TA = -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
IO PIN: GENERAL DATA
1-Wire Pullup Voltage
VPUP
(Note 2)
1.71
1.89
V
1-Wire Pullup Resistance
RPUP
VPUP = 1.8V ±5% (Note 3)
300
750
Ω
Input Capacitance
Input Load Current
High-to-Low Switching Threshold
CIO
IL
(Notes 4, 5)
1500
IO pin at VPUP
pF
5
19.5
µA
VTL
(Notes 6, 7)
Input Low Voltage
VIL
(Notes 2, 8)
Low-to-High Switching Threshold
VTH
(Notes 6, 9)
Switching Hysteresis
VHY
(Notes 6, 10)
Output Low Voltage
VOL
IOL = 4mA (Note 11)
Recovery Time
tREC
RPUP = 750Ω (Notes 2, 12)
5
µs
Time-Slot Duration
tSLOT
(Notes 2, 13)
13
µs
0.65 x VPUP
V
0.3
0.75 x VPUP
0.3
V
V
V
0.4
V
IO PIN: 1-Wire RESET, PRESENCE-DETECT CYCLE
Reset Low Time
tRSTL
(Note 2)
48
Reset High Time
tRSTH
(Note 14)
48
80
µs
Presence-Detect Sample Time
tMSP
(Notes 2, 15)
8
10
µs
Write-Zero Low Time
tW0L
(Notes 2, 16)
8
16
µs
Write-One Low Time
tW1L
(Notes 2, 16)
0.25
2
µs
tRL
(Notes 2, 17)
0.25
2-d
µs
tMSR
(Notes 2, 17)
tRL + d
2
µs
VPUP = 1.89V (Notes 5, 18)
1
mA
10
ms
200
ms
µs
IO PIN: 1-Wire WRITE
IO PIN: 1-Wire READ
Read Low Time
Read Sample Time
EEPROM
Programming Current
IPROG
Programming Time for a 32-Bit
Segment or Page Protection
tPRD
(Note 19)
Programming Time for the Secret
tPRS
Refer to the full data sheet.
Write/Erase Cycling Endurance
NCY
TA = +85°C (Notes 21, 22)
Data Retention
tDR
TA = +85°C (Notes 23, 24, 25)
www.analog.com
100k
—
10
Years
Analog Devices │ 2
ABRIDGED DATA SHEET
DS28EL25
DeepCover Secure Authenticator
with 1-Wire SHA-256 with 4Kb User EEPROM
ELECTRICAL CHARACTERISTICS (continued)
(TA = -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
1
mA
3
ms
SHA-256 ENGINE
Computation Current
ICSHA
Computation Time
tCSHA
Refer to the full data sheet.
Note 1: Limits are 100% production tested at TA = +25°C and/or TA = +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 VPUP 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: VTL, VTH, and VHY are a function of the internal supply voltage, which is a function of VPUP, RPUP, 1-Wire timing, and
capacitive loading on IO. Lower VPUP, higher RPUP, shorter tREC, and heavier capacitive loading all lead to lower values of
VTL, VTH, and VHY.
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 VILMAX 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 VTH is crossed during a rising edge on IO, the voltage on IO must drop by at least VHY 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/(tW0LMIN + tRECMIN).
Note 14: An additional reset or communication sequence cannot begin until the reset high time has expired.
Note 15: Interval after tRSTL during which a bus master can read a logic 0 on IO if there is a DS28EL25 present. The power-up presence detect pulse could be outside this interval. See the Typical Operating Characteristics for details.
Note 16: ε in Figure 11 represents the time required for the pullup circuitry to pull the voltage on IO up from VIL to VTH. The actual
maximum duration for the master to pull the line low is tW1LMAX + tF - ε and tW0LMAX + tF - ε, respectively.
Note 17: δ in Figure 11 represents the time required for the pullup circuitry to pull the voltage on IO up from VIL to the input-high
threshold of the bus master. The actual maximum duration for the master to pull the line low is tRLMAX + tF.
Note 18: Current drawn from IO during the EEPROM programming interval or SHA-256 computation. The pullup circuit on IO during the programming and computation interval should be such that the voltage at IO is greater than or equal to VPUPMIN.
A low-impedence bypass of RPUP activated during programming and computation is the recommended way to meet this
requirement.
Note 19: Refer to the full data sheet.
Note 20: Refer to the full data sheet.
21: Write-cycle endurance is tested in compliance with JESD47G.
22: Not 100% production tested; guaranteed by reliability monitor sampling.
23: Data retention is tested in compliance with JESD47G.
24: 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 25: EEPROM writes can become nonfunctional after the data retention time is exceeded. Long-term storage at elevated temperatures is not recommended.
Note
Note
Note
Note
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Analog Devices │ 3
ABRIDGED DATA SHEET
DS28EL25
DeepCover Secure Authenticator
with 1-Wire SHA-256 with 4Kb User EEPROM
ELECTRICAL CHARACTERISTICS (continued)
(TA = -40°C to +85°C, unless otherwise noted.) (Note 1)
Note 26: Refer to the full data sheet.
Typical Operating Characteristics
(VPUP = 1.71V, VIL = 0.3V)
Pin Configuration
TOP VIEW
POWER-UP TIME
DS28EL25 toc01
180
160
DS28EL25
N.C. 1
120
IO 2
100
GND 3
+
6 N.C.
28L25
ymrrF
TIME (ms)
140
5 N.C.
4 N.C.
EP
80
60
TDFN
(3mm × 3mm)
40
20
0
-40
-20
0
20
40
TEMPERATURE (°C)
60
80
Pin Description
PIN
NAME
3
GND
2
IO
1, 4,
5, 6
N.C.
—
www.analog.com
EP
FUNCTION
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.
Analog Devices │ 4
ABRIDGED DATA SHEET
DS28EL25
DeepCover Secure Authenticator
with 1-Wire SHA-256 with 4Kb 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/DS28EL25
and click on Request Full Data Sheet.
Ordering Information
PART
DS28EL25Q+T
TEMP RANGE
-40°C to +85°C
Package Information
PIN-PACKAGE
6 TDFN-EP* (2.5k pcs)
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
*EP = Exposed pad.
www.analog.com
For the latest package outline information and land patterns (footprints), 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.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
6 TDFN-EP
T633+2
21-0137
90-0058
Analog Devices │ 43
ABRIDGED DATA SHEET
DS28EL25
DeepCover Secure Authenticator
with 1-Wire SHA-256 with 4Kb User EEPROM
Revision History
REVISION
NUMBER
REVISION
DATE
0
12/12
Initial release
1
6/21
Updated Electrical Characteristics table, Detailed Description
DESCRIPTION
PAGES
CHANGED
—
2, 32
Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is
assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that
may result from its use.Specifications subject to change without notice. No license is granted by implicationor
otherwise under any patent or patent rights of Analog Devices. Trademarks andregistered trademarks are the
property of their respective owners.
w w w . a n a l o g . c o m
Analog Devices │ 44