MAX66240ISA+T - Maxim Integrated

General Description

DeepCover® embedded security solutions cloak sensitive

data under multiple layers of advanced physical security

to provide the most secure key storage possible.

The DeepCover Secure Authenticator (MAX66240) is a

transponder IC that combines an ISO/IEC 15693 and ISO

18000-3 Mode 1-compatible RF front-end, a FIPS 180-

based SHA-256 engine, and 4096 bits of user EEPROM

in a single chip. A bidirectional security model enforces

two-way authentication between a host system and the

MAX66240. Each device has its own guaranteed unique

64-bit ROM ID that is factory programmed into the chip.

This ROM ID is used as a fundamental input parameter

for cryptographic operations and serves as an electronic

serial number within the application.

Features and Benets

●Dedicated Hardware-Accelerated SHA Engine

●Strong Authentication with a High Bit Count User-

Programmable Secret and Input Challenge

●4096 Bits of User EEPROM with User-Programmable

R/W Protection Options Including OTP/EPROM

Emulation Mode

●Unique Factory-Programmed 64-Bit Identification

Number

●ISO/IEC 15693: Up to 26kbps

●±2kV HBM ESD Protection for All Pins

Applications

●Access Control

●Asset Tracking

● Printer Cartridge Conguration and Monitoring

●Medical Sensor Authentication and Calibration

●System Intellectual Property Protection

Ordering Information appears at end of data sheet.

DeepCover is a registered trademark of Maxim Integrated

Products, Inc.

For related parts and recommended products to use with this part, refer

to www.maximintegrated.com/MAX66240.related.

13.56MHz READER

TRANSMITTER

RECEIVER

TX_OUT

RX_IN

MAGNETIC

COUPLING

ANTENNA

MAX66240

SWITCHED

LOAD

IC LOAD

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

219-0042; Rev 3; 4/18

Typical Application Circuit

EVALUATION KIT AVAILABLE

ABRIDGED DATA SHEET

Voltage Range on Any Pin Relative to GND ........-0.5V to +4.0V

Maximum RMS Current, AC1 to AC2 ................................. 30mA

Maximum Incident Magnetic Field Strength

(ISO/IEC 7810-compliant antenna) ................... 141.6dBµA/m

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

Junction-to-Ambient Thermal Resistance (θJA).........136°C/W

Junction-to-Case Thermal Resistance (θJC) ...............38°C/W

TDFN

Junction-to-Ambient Thermal Resistance (θJA)...........60°C/W

Junction-to-Case Thermal Resistance (θJC) ...............30°C/W

(TA = -40°C to +85°C, unless otherwise noted.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SHA-256 ENGINE

Computation Time tCSHA (Note 3) 2 ms

EEPROM

Programming Time for a 32-Bit

Page Block or Protection tPROG (Note 4) 10 ms

Write/Erase Cycling Endurance NCY TA = +85°C (Notes 5, 6) 100k —

Data Retention tDR TA = +85°C (Notes 7, 8, 9) 10 Years

RF PORT

Carrier Frequency fC(Note 10) 13.553 13.560 13.567 MHz

Internal Tuning Cap CTUN f = 13.56MHz (Note 11) 27.5 pF

Operating Field HISO (Note 10) 150 5000 mA/m

Activation Field Strength

HMIN_10 TA = +25°C, 10% modulation

(Notes 11, 12) 94

dBµA/mHMIN_30 TA = +25°C, 30% modulation

(Notes 11, 12) 104

HMIN_100 TA = +25°C, 100% modulation

(Notes 11, 12) 103.5

Write/SHA Field Strength HWR TA = +25°C (Notes 11, 12, 13) 113 dBµA/m

RF Access in Progress Time tRFAIP 1.1 ms

10% Carrier Modulation Index

MI = (A - B)/(A + B) CMI_10 (Notes 10, 11) 10 30 %

100% Carrier Modulation Index

MI = (A - B)/(A + B) CMI_100 (Notes 10, 11) 95 100 %

10% Modulation Min Pulse

Width t1 MIN Refer to ISO 15693-2 Section

7.1 (Notes 11, 14) 7.0 µs

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

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Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer

board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.

Absolute Maximum Ratings

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.

(Note 1)

Package Thermal Characteristics

Electrical Characteristics

ABRIDGED DATA SHEET

(TA = -40°C to +85°C, unless otherwise noted.) (Note 2)

Note 2: Limits are 100% production tested at TA = +25°C or TA = +85°C. Limits over the operating temperature range and relevant

supply voltage range are guaranteed by design and characterization. Typical values are at +25°C.

Note 3: For commands where the tCSHA interval occurs see the applicable communication examples sections. For RF commands,

the interval begins after the EOF of a valid request frame. The interval ends once the device’s self-timed SHA-256 compu-

tation cycle is complete.

Note 4: For commands where the tPROG interval occurs see the applicable communication examples sections. For RF commands,

the interval begins after the EOF of a valid request frame. The interval ends once the device’s self-timed EEPROM write

cycle is complete.

Note 5: Write-cycle endurance is tested in compliance with JESD47G.

Note 6: Not 100% production tested; guaranteed by reliability qualification.

Note 7: Data retention is tested in compliance with JESD47G.

Note 8: 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 9: EEPROM writes can become nonfunctional after the data-retention time is exceeded. Long-term storage at elevated tem-

peratures is not recommended.

Note 10: System requirement.

Note 11: Guaranteed by design and/or characterization only. Not production tested.

Note 12: Characterized in accordance with ISO/IEC 10373-7.

Note 13: Applies to Read/Write Scratchpad (writing), Write Memory, Compute and Read Page MAC, Set Protection, Authenticated

Write Memory RF Setup, Authenticated Write Memory RF Execute, Authenticated Set Protection RF Setup, and

Authenticated Set Protection RF Execute commands.

Note 14: Field strength between 350mA/m and 3A/m.

Note 15: Field strength between 350mA/m and 5A/m.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

10% Modulation Max Pulse

Width t1 MAX Refer to ISO 15693-2 Section

7.1 (Note 11) 9.44 µs

10% Modulation Min Low Time t2 MIN Refer to ISO 15693-2 Section

7.1 (Notes 11, 14) 7.0 µs

10% Modulation Max Low Time t2 MAX Refer to ISO 15693-2 Section

7.1 (Note 11) 9.44 µs

10% Modulation Min Rise Time t3 MIN Refer to ISO 15693-2 Section

7.1 (Note 11) 0 µs

10% Modulation Max Rise Time t3 MAX Refer to ISO 15693-2 Section

7.1 (Notes 11, 14) 2.5 µs

100% Modulation Min Pulse

Width t1 MIN Refer to ISO 15693-2 Section

7.1 (Notes 11, 15) 6.5 µs

100% Modulation Min Pulse

Width t1 MAX Refer to ISO 15693-2 Section

7.1 (Note 11) 9.44 µs

100% Modulation Max Pulse

Width t2 MIN Refer to ISO 15693-2 Section

7.1 (Notes 11, 15) 6.5 µs

100% Modulation Max Low

Time t2 MAX Refer to ISO 15693-2 Section

7.1 (Note 11) 9.44 µs

100% Modulation Min Rise

Time t3 MIN Refer to ISO 15693-2 Section

7.1 (Note 11) 0 µs

100% Modulation Max Rise

Time t3 MAX Refer to ISO 15693-2 Section

7.1 (Notes 11, 15) 3.0 µs

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

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Electrical Characteristics (continued)

ABRIDGED DATA SHEET

PIN NAME FUNCTION

SO TDFN

1, 4–8 1, 3, 5–10 D.N.C. Do Not Connect

2 2 AC2 Antenna Connection

3 4 AC1 Antenna Connection

TDFN

TOP VIEW

D.N.C.

AC2

AC1

D.N.C.

MAX66240

+D.N.C.

D.N.C.

AC1

D.N.C.

AC2

D.N.C.

MAX66240

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

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Pin Descriptions

Pin Congurations

ABRIDGED DATA SHEET

Detailed Description

The MAX66240 transponder combines an ISO 15693 RF

front-end, a SHA-256 engine, 4096 bits of user EEPROM

organized as 16 256-bit pages, protection control, status

memory, and a 64-bit ROM ID in a single chip. A 256-bit

scratchpad assists when installing a new secret or stores

the challenge when computing a page MAC.

It is common for a secure authentication IC to be attacked

using a variety of sophisticated die-level methods to

extract secure data, reverse device settings, etc., in an

effort to compromise a system security implementation.

To provide the highest affordable protection against this

inevitable malicious attack, the MAX66240 employs pro-

prietary die-level physical techniques, circuits, and crypto

methods to protect sensitive data, control signals, and

control settings.

There are multiple programmable options for the 4Kb user

array including unrestricted read/write and four protection

modes: read protection, write protection, EPROM emula-

tion mode, and authentication protection. Read protection

prevents user read-access to the memory, which effec-

tively extends the secret into the protected memory. The

data remains accessible only for the SHA-256 engine.

Write protection prevents changes to the memory data.

EPROM emulation mode logically ANDs memory data

with incoming new data, which allows changing bits from

1 to 0, but not vice versa. By changing one bit at a time,

this mode could be used to create a nonvolatile, nonreset-

table counter. EPROM emulation mode requires that the

memory is not write protected. Authentication protection,

if activated, requires that the host prove itself as authentic

(i.e., knows the MAX66240 secret) to modify the memory

by supplying a correct MAC that is based on the device

secret, its ROM ID, memory data, and the new data to

be copied to EEPROM. If the authentication hurdle is

passed, the write protection and EPROM emulation mode

protections still determine the effect of the write access.

Any protection, if activated, applies to individual memory

pages. As a factory default, none of the protections is

activated. Once authentication protection is activated, the

reader must authenticate itself for memory writes as well

as for additional changes to the memory protection.

In addition to its important use as a unique data value in

cryptographic SHA-256 computations, the device’s 64-bit

ROM ID can be used to electronically identify the object

to which the MAX66240 is associated. Applications of the

MAX66240 include, access control, asset tracking, printer

cartridge configuration and monitoring, medical sensor

authentication and calibration, and system intellectual

property protection.

Overview

The block diagram in Figure 1 shows the relationships

between the major control and memory sections of the

MAX66240.

Figure 2 shows the applicable commands and the

affected data fields. The network function commands

allow the reader to identify all transponders in its range

and to change their state, e.g., to select one for further

communication. The protocol required for these network

function commands is described in the Network Function

Commands section. The memory and control functions

fall into five categories: ISO 15693 generic commands,

secret installation, memory access, protection setting,

and MAC computation. The protocol for these com-

mands is described in the Memory and Control Function

Commands section. All data is read and written least

significant bit (LSb) first, starting with the least significant

byte (LSB).

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

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ABRIDGED DATA SHEET

Figure 1. Block Diagram

ISO 15693

PROTOCOL

SHA-256

ENGINE

DEVICE FUNCTION

CONTROL

MEMORY

MANAGEMENT

MAX66240

VOLTAGE

REGULATOR

FRONT

END

64 BIT UID

64 BIT UID ROM ID

SCRATCHPAD

SECRET

4kBIT EEPROM

ARRAY

AC2

AC1

DATA

MOD

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

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ABRIDGED DATA SHEET

Figure 2. Commands Overview

NETWORK FUNCTION

COMMANDS

COMMAND

TYPE:

AVAILABLE

COMMANDS:

INVENTORY

STAY QUIET

SELECT

RESET TO READY

DATA FIELD

AFFECTED:

UID, AFI, DSFID

UID

(N/A)

GET SYSTEM INFORMATION

WRITE MEMORY

READ MEMORY

READ SINGLE BLOCK

READ MULTIPLE BLOCKS

SET PROTECTION

READ STATUS

READ/WRITE SCRATCHPAD

LOAD AND LOCK SECRET

COMPUTE AND LOCK SECRET

COMPUTE AND READ PAGE MAC

AUTHENTICATED WRITE

MEMORY RF SETUP

AUTHENTICATED WRITE

MEMORY RF EXECUTE

AUTHENTICATED SET

PROTECTION RF SETUP

AUTHENTICATED SET

PROTECTION RF EXECUTE

GET 1-WIRE ROM ID

WRITE AFI

LOCK AFI

WRITE DSFID

LOCK DSFID

UID, AFI, DSFID, CONSTANTS

MFGCODE, USER MEMORY, PROTECTION

SETTINGS

MFGCODE, USER MEMORY, PROTECTION

SETTINGS

SELECTED MEMORY BLOCK, PROTECTION

SETTINGS

SELECTED MEMORY BLOCKS, PROTECTION

SETTINGS

MFGCODE, PROTECTION SETTINGS

MFGCODE, PROTECTION SETTINGS,

PERSONALITY BYTES

MFGCODE, SCRATCHPAD

MFGCODE, SECRET AND LOCK STATUS,

SCRATCHPAD

MFGCODE, SECRET AND LOCK STATUS, USER

MEMORY, SCRATCHPAD, PROTECTION SETTING

MFGCODE, SECRET, ROM ID, USER MEMORY,

SCRATCHPAD

MFGCODE, USER MEMORY, PAGE BLOCK

NUMBER, SECRET, PROTECTION SETTINGS

MFGCODE, USER MEMORY

MFGCODE, MEMORY PAGE NUMBER, SECRET,

PROTECTION SETTINGS

MFGCODE, PROTECTION SETTINGS

MFGCODE, ROM ID

AFI BYTE

AFI LOCK STATUS

DSFID BYTE

DSFID LOCK STATUS

MEMORY AND CONTROL

FUNCTION COMMANDS

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

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ABRIDGED DATA SHEET

Parasite Power

The MAX66240 receives all energy necessary for its

operation from the surrounding RF field, which needs to

have a minimum strength as specified in the Electrical

Characteristics table.

Unique Identication Number (UID)

Each MAX66240 contains a factory-programmed and

locked identification number that is 64 bits long (Figure 3).

The lower 28 bits are the serial number of the chip. The

upper 36 bits are fixed at E02B00800h. The code in bit

locations 49 to 56 identifies the chip manufacturer, accord-

ing to ISO/IEC 7816-6/AM1. This code is 2Bh for Maxim.

The UID is read accessible through the Inventory and Get

System Information commands.

ROM ID

The read-only ROM ID is similar to the UID (Figure 4). The

first 8 bits are a family code, which is E0h. The next 28

bits are a unique serial number. The next 20 bits are fixed

at 2B000h. The last 8 bits are a cyclic redundancy check

(CRC) of the first 56 bits. The CRC is generated using the

polynomial X8 + X5 + X4 + 1 (Figure 5). Additional infor-

mation about this CRC is available in Application Note

27: Understanding and Using Cyclic Redundancy Checks

with Maxim iButton® Products. The ROM ID is part of the

input data to the SHA-256 engine. It is read accessible

through the command Get 1-Wire ROM ID.

iButton is a registered trademark of Maxim Integrated Products,

Inc.

Figure 3. 64-Bit UID

Figure 4. 64-Bit ROM ID

Figure 5. 8-Bit CRC for the ROM ID

MSb LSb

64 57 48 4556 49 44 37 36 29 28 1

E0h 0h2Bh 04h 00h Serial Number

MSb

MSb LSb

8-bit

CRC Code 2Bh 0h 00h 28-bit

Serial Number

8-bit Family Code

(E0h)

MSb LSb

LSb

MSb LSb

POLYNOMIAL = X

+ X

+ 1

MSb

1ST

STAGE

2ND

STAGE

3RD

STAGE

4TH

STAGE

5TH

STAGE

6TH

STAGE

7TH

STAGE

8TH

STAGE

LSb

INPUT DATA

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

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Memory Resources

The memory of the MAX66240 consists of user

EEPROM, secret memory, an SRAM scratchpad, per-

sonality registers, ROM ID, and two ISO 15693-specific

bytes. Table 1 shows the size, access mode, and purpose

of the various memory areas. Brackets around an access

mode indicate possible restrictions, such as write protec-

tion or read protection.

The user memory is organized as 16 pages of 32 bytes

each (Figure 6). A page is divided into 8 page blocks of

32 bits each. With the MAX66240, the page protection

applies to individual memory pages. The user memory is

written in page blocks. If not read protected, the memory

can be read starting at any page block of any page. The

protocol allows reading multiple page blocks and pages up

to the end of the memory in a single read command flow.

The secret is either directly written (loaded) or computed.

This write access always encompasses the entire 32-byte

secret. To protect against transmission errors, the new

secret (loading) or a partial secret (computing) is first

written to the scratchpad from where it can be read for

verification. As the name implies, the secret memory is

not user readable. To protect a secret from changes, it

must be write protected (locked).

Page protection control is activated through the Write

Page Protection command. Besides write protection, read

protection and EPROM emulation mode, the MAX66240

supports authentication protection. If authentication pro-

tection is activated, changes to the page protection set-

tings as well as writing to the protected user memory

require that the reader provide a valid MAC for the opera-

tion. Once a protection is activated, it cannot be reversed.

The protection settings as well as the personality registers

are read accessible through the Read Status command.

Note that the ISO 15693 standard commands Read

Single Block and Read Multiple Blocks do not address the

user memory by page number and page block number.

Instead, they use absolute block numbers counting from 0

to 127. Figure 7 shows how these absolute numbers map

to the user memory.

Table 1. Memory Resources

NAME SIZE

(BYTES) ACCESS MODE PURPOSE

User Memory

(EEPROM) 512 (Read), (Write),

Internal Read Application-specic data storage; also used for MAC computations.

Scratchpad

(SRAM) 32 Read, Write,

Internal Read

Intermediate data storage when installing a secret; also used to

store the challenge for a MAC computation.

Personality Registers 4Read,

Internal Read

Lock status indicator for the secret and read access to the device’s

manufacturer ID (factory preprogrammed parts).

ROM ID 8 Read,

Internal Read Used for MAC computations.

Application Family

Identier (AFI) 1 Read, (Write)

Can be used during the inventory phase to narrow the number

of transponders that participate in the discovery or anti-collision

process.

Data Storage Format

Identier (DSFID) 1 Read, (Write) User byte that can provide details on how the data in the user

memory is structured.

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

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ABRIDGED DATA SHEET

Figure 7. User Memory Access Using Absolute Block Numbers

Figure 6. User Memory Map

PG. BLOCK 7 PG. BLOCK 6 PG. BLOCK 5 PG. BLOCK 4 PG. BLOCK 3 PG. BLOCK 2 PG. BLOCK 1 PG. BLOCK 0

Page 0

Page 1

Page 2

Page 3

Page 4

Page 5

Page 6

Page 7

Page 8

Page 9

Page 10

Page 11

Page 12

Page 13

Page 14

Page 15

PG. BLOCK 7 PG. BLOCK 6 PG. BLOCK 5 PG. BLOCK 4 PG. BLOCK 3 PG. BLOCK 2 PG. BLOCK 1 PG. BLOCK 0

Page 0 Block 7 Block 6 Block 5 Block 4 Block 3 Block 2 Block 1 Block 0

Page 1 Block 15 Block 14 Block 13 Block 12 Block 11 Block 10 Block 9 Block 8

Page 2 Block 23 Block 22 Block 21 Block 20 Block 19 Block 18 Block 17 Block 16

Page 3 Block 31 Block 30 Block 29 Block 28 Block 27 Block 26 Block 25 Block 24

Page 4 Block 39 Block 38 Block 37 Block 36 Block 35 Block 34 Block 33 Block 32

Page 5 Block 47 Block 46 Block 45 Block 44 Block 43 Block 42 Block 41 Block 40

Page 6 Block 55 Block 54 Block 53 Block 52 Block 51 Block 50 Block 49 Block 48

Page 7 Block 63 Block 62 Block 61 Block 60 Block 59 Block 58 Block 57 Block 56

Page 8 Block 71 Block 70 Block 69 Block 68 Block 67 Block 66 Block 65 Block 64

Page 9 Block 79 Block 78 Block 77 Block 76 Block 75 Block 74 Block 73 Block 72

Page 10 Block 87 Block 86 Block 85 Block 84 Block 83 Block 82 Block 81 Block 80

Page 11 Block 95 Block 94 Block 93 Block 92 Block 91 Block 90 Block 89 Block 88

Page 12 Block 103 Block 102 Block 101 Block 100 Block 99 Block 98 Block 97 Block 96

Page 13 Block 111 Block 110 Block 109 Block 108 Block 107 Block 106 Block 105 Block 104

Page 14 Block 119 Block 118 Block 117 Block 116 Block 115 Block 114 Block 113 Block 112

Page 15 Block 127 Block 126 Block 125 Block 124 Block 123 Block 122 Block 121 Block 120

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

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ISO/IEC 15693 Interface

The communication between an HF reader and MAX66240

(transponder) is a master-transponder type transaction,

and is based on the exchange of data packets. The

reader initiates every transaction; only one side (reader

or transponder) transmits information at any time. Each

data packet begins with a start-of-frame (SOF) pattern

and ends with an end-of-frame (EOF) pattern. A data

packet delimited by an SOF and an EOF is called a frame

(Figure 8). The last 2 bytes of an ISO 15693 frame are

an inverted 16-bit CRC of the preceding data generated

according to the CRC-16-CCITT polynomial X16 + X12 +

X5 + 1 (Figure 9). This CRC is transmitted with the LSB

first. For more details on the CRC-16-CCITT, refer to ISO

15693-3, Annex C. Frame information is modulated on

a 13.56MHz carrier. The subsequent paragraphs are a

concise description of the required modulation, coding,

and basic timing.

Figure 8. ISO/IEC 15693 Frame Format

Figure 9. CRC-16-CCITT Generator

SOF 1 OR MORE DATA BYTES CRC (LSB) CRC (MSB) EOF

TIME

POLYNOMIAL = X16 + X12 + X5 + 1

9TH

STAGE

10TH

STAGE

11TH

STAGE

12TH

STAGE

X8X9X10 X11 X12

13TH

STAGE

14TH

STAGE

15TH

STAGE

16TH

STAGE

X13 X14 X15

LSb

INPUT DATA

MSb

1ST

STAGE

2ND

STAGE

3RD

STAGE

4TH

STAGE

X0X1X2X3

6TH

STAGE

7TH

STAGE

8TH

STAGE

X5X6X7

5TH

STAGE

X16

MAX66240 DeepCover Secure Authenticator with

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Reader to Transponder Communication

The communication from reader to transponder uses

amplitude modulation (Figure 10); the modulation index

can be either in the range of 10% to 30% or 100% (ISO

15693-2, Section 7.1). The standard defines two pulse-

position data coding modes. The “1 out of 256” data

coding mode transmits one 1 byte in 4.833ms, equivalent

to a data rate of 1655bps (Figure 11). The location of a

modulation pause during the 4.833ms conveys the value

of the byte. The “1 out of 4” data coding mode

transmits

2 bits in 75.52µs, equivalent to a data rate of 26,484bps

(Figure 12

)

. The location of a modulation pause during

the 75.52µs conveys the value of the 2 bits. A byte is

transmitted as a concatenation of four 2-bit transmissions,

with the least significant 2 bits of the byte being transmit-

ted first. The transmission of the SOF pattern also takes

75.52µs. The SOF pattern has two modulation pauses.

The position of the second pause determines whether the

frame uses the “1 out of 256” or “1 out of 4” data coding

mode (Figure 13 and Figure 14, respectively). The trans-

mission of the EOF pattern takes 37.76µs; the EOF is

the same for both coding modes and has one modulation

pause (Figure 15). For full details, refer to ISO 15693-2,

Sections 7 and 8.

Figure 10. Reader to Transponder Modulation

CARRIER

AMPLITUDE

105%

95%

60%

100% MODULATION

CARRIER

AMPLITUDE

10% MODULATION

MI = (A - B)/(A + B)

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

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Figure 11. Reader to Transponder “1 Out of 256” Data Coding

Figure 12. Reader to Transponder “1 Out of 4” Data Coding (Carrier Not Shown)

PULSE-

MODULATED

CARRIER

01234......

....... . . ... . . ..

.....

~ 9.44µs

~ 18.88µs

~ 4.833ms

PULSE POSITION "00"

PULSE POSITION "01" (1 = LSB)

PULSE POSITION "10" (0 = LSB)

PULSE POSITION "11"

~ 9.44µs ~ 9.44µs

~ 75.52µs

~ 28.32µs

~ 47.20µs ~ 9.44µs

~ 9.44µs

~ 75.52µs

~ 66.08µs ~ 9.44µs

~ 75.52µs

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

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Figure 13. Reader to Transponder SOF for “1 Out of 256” Data Coding (Carrier Not Shown)

Figure 14. Reader to Transponder SOF for “1 Out of 4” Data Coding (Carrier Not Shown)

Figure 15. Reader to Transponder EOF (Identical for Both Coding Modes, Carrier Not Shown)

~ 9.44µs~ 9.44µs

~ 37.76µs ~ 37.76µs

~ 9.44µs

~ 37.76µs ~ 37.76µs

~ 9.44µs ~ 9.44µs

~ 9.44µs

~ 37.76µs

~ 9.44µs

MAX66240 DeepCover Secure Authenticator with

ISO 15693, SHA-256, and 4Kb User EEPROM

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Transponder to Reader Communication

The Subcarrier_flag bit in the request data frame specifies

the use of one or two subcarrier in the response frame.

For the one subcarrier case, the subcarrier frequency

is 423.75kHz. For the two subcarrier case, the subcar-

rier frequencies are 423.75kHz and 484.28kHz. The

Data_rate_flag bit in the request data frame specifies the

response frame data rate. Low data rate is approximately

6,600bps, and high data rate is approximately 26,500bps.

The data rate varies slightly depending on the use of one

or two subcarriers. The LSb is transmitted first.

In the single subcarrier high data rate case, one bit is

transmitted in 37.76µs. For a logic 0, the transponder

modulates for 16 cycles then does not modulate for 16

cycles, which is repeated 8 times. This is followed by 256

cycles of no modulation. For a logic 1, the transponder

does not modulate for 256 cycles. It then modulates for

16 cycles then does not modulate for 16 cycles, which

is repeated 8 times. An SOF or EOF is transmitted in

approximately 151µs. For an SOF, the transponder does

not modulate for 768 cycles. It then modulates for 16

cycles then does not modulate for 16 cycles, which is

repeated 24 times. This is followed by a logic 1. For an

EOF, the transponder sends a logic 0. It then modulates

for 16 cycles then does not modulate for 16 cycles, which

is repeated 24 times. This is followed by no modulation for

768 cycles. See Figure 16 and Figure 18 for more details.

For low data rate, multiply all cycle counts and times by 4.

In the two subcarrier low data rate case, one bit is transmit-

ted in 37.46µs. For a logic 0, the transponder modulates

for 16 cycles then does not modulate for 16 cycles, which

is repeated 8 times. Next, the transponder modulates for

14 cycles then does not modulate for 14 cycles, which is

repeated 9 times. For a logic 1, the transponder modu-

lates for 14 cycles then does not modulate for 14 cycles,

which is repeated 9 times. Next, the transponder modu-

lates for 16 cycles then does not modulate for 16 cycles,

which is repeated 8 times. An SOF or EOF is transmitted

in approximately 149.8µs. For an SOF, the transponder

modulates for 14 cycles then does not modulate for 14

cycles, which is repeated 27 times. Next, the transponder

modulates for 16 cycles then does not modulate for 16

cycles, which is repeated 24 times. This is followed by a

logic 1. For an EOF, the transponder sends a logic 0. It

then modulates for 16 cycles then does not modulate for

16 cycles, which is repeated 24 times. Next, the transpon-

der modulates for 14 cycles then does not modulate for

14 cycles, which is repeated 27 times. See Figure 17 and

Figure 19 for more details. For low data rate, multiply all

cycle counts and times by 4.

Figure 16. Transponder to Reader Coding, Single Subcarrier Bit Coding (High Data-Rate Timing)

TRANSMITTING A ZERO

TRANSMITTING A ONE

423.75kHz, ~ 18.88µs ~ 18.88µs

~ 37.76µs

~ 18.88µs 423.75kHz, ~ 18.88µs

~ 37.76µs

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Figure 17. Transponder to Reader Coding, Two Subcarriers Bit Coding (High Data-Rate Timing)

Figure 18. Transponder to Reader SOF, One Subcarrier (High Data Rate)

Figure 19. Transponder to Reader SOF, Two Subcarriers (High Data Rate)

TRANSMITTING A ZERO

TRANSMITTING A ONE

423.75kHz, ~ 18.88µs

~ 37.46µs

484.28kHz, ~ 18.58µs

484.28kHz, ~ 18.58µs 423.75kHz, ~ 18.88µs

423.75kHz 423.75kHz

~ 56.64µs ~ 56.64µs ~ 37.76µs

484.28kHz484.28kHz 423.75kHz 423.75kHz

~ 55.75µs ~ 56.64µs ~ 37.46µs

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ISO 15693 Transponder States

and State Transitions

ISO 15693 defines four transponder states and three

address modes. The states are power-off, ready, quiet,

and selected. The address modes are nonaddressed,

addressed, and select. The addressed mode requires that

the reader include the transponder’s UID in the request.

Figure 20 shows how the Reset to Ready, Stay Quiet, and

Select commands respond when changing the transpon-

der’s state. Table 2 shows how other commands respond

depending on address mode and the transponder’s state.

Note that Stay Quiet never generates a response. For full

details, refer to ISO 15693-2, Section 7.

Power-Off State

This state applies if the transponder is outside the read-

er’s RF field. A transponder transitions to the power-off

state when leaving the power-delivering RF field. When

entering the RF field, the transponder automatically tran-

sitions to the ready state.

Ready State

In this state, a transponder has enough power to perform

any of its functions. The purpose of the ready state is to

have the transponder population ready to process the

inventory command as well as other commands sent in

the addressed or nonaddressed mode. A transponder

can exit the ready state and transition to the quiet or the

selected state upon receiving the Stay Quiet or Select

command sent in addressed mode.

Quiet State

In this state, a transponder has enough power to perform

any of its functions. The purpose of the quiet state is to

silence transponders with which the reader does not want

to communicate. Only commands sent with the addressed

mode are processed. This way the reader can use the

nonaddressed mode for communication with remaining

transponders in the ready state. A transponder can exit the

quiet state and transition to the ready state upon receiving

the Reset to Ready command in addressed or nonad-

dressed mode. It can also transition to the selected state

upon receiving Select commands sent in addressed mode.

Selected State

In this state, a transponder has enough power to perform

any of its functions. The purpose of the selected state is

to isolate the transponder with which the reader wants

to communicate. Commands are processed regardless

of the address mode in which they are sent, including

the Inventory command. With multiple transponders in

the RF field, the reader can put one transponder in the

selected state, leaving all others in the ready state. For a

transponder in the selected state, the reader can use the

selected mode, which keeps the request data packets as

short as with the nonaddressed mode. A new transponder

entering the RF field will not disturb communication since

it powers up in the ready state. A transponder can exit

the selected state and transition to the ready state upon

receiving the Reset to Ready command sent in nonad-

dressed or addressed mode. It can also transition to the

quiet state upon receiving the Stay Quiet command sent

in the addressed mode. A transponder also transitions

from selected to ready upon receiving a Select command

if the UID in the request is different from the transponder’s

own UID. In this case, the reader’s intention is to transi-

tion another transponder with the matching UID to the

selected state. If the transponder already in the selected

state does not recognize the command, e.g., due to a bit

error, two transponders could be in the selected state. To

prevent this from happening, the reader should use the

Reset to Ready or the Stay Quiet command to transition

a transponder out of the selected state.

Table 2. Command Response vs. Transponder State and Address Mode Combinations

TRANSPONDER

STATES

ADDRESS MODES

NONADDRESSED MODE

(Address_ag = 0;

Select_ag = 0)

ADDRESSED MODE

(Address_ag = 1;

Select_ag = 0)

SELECT MODE

(Address_ag = 0;

Select_ag = 1)

Power-Off (Inactive) (Inactive) (Inactive)

Ready Respond Respond Do not respond

Quiet Do not respond Respond Do not respond

Selected Respond Respond Respond

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Figure 20. ISO 15693 State Transition Diagram

POWER-OFF

READY

SELECTEDQUIET

IN FIELD

NOTE 1

NOTE 3

OUT OF FIELD

RESET TO READY

[S]

OUT OF FIELD

NOTE 2

RESPONSE LEGEND:

NOTE 1: THE TRANSPONDER PROCESSES THE INVENTORY COMMAND, AND PROCESSES OTHER COMMANDS IN NONADDRESSED

MODE OR ADDRESSED MODE WITH MATCHING UID.

NOTE 2: THE TRANSPONDER DOES NOT PROCESS THE INVENTORY COMMAND, AND PROCESSES OTHER COMMANDS IN

ADDRESSED MODE WITH MATCHING UID.

NOTE 3: THE TRANSPONDER PROCESSES THE INVENTORY COMMAND, AND PROCESSES OTHER COMMANDS IN NONADDRESSED

MODE, ADDRESSED MODE WITH MATCHING UID, OR SELECT MODE.

RESPONSE TO

RESET TO READY

STAY QUIET [A],

MATCHING UID

SELECT [A],

NONMATCHING UID

RESPONSE TO

SELECT

NO RESPONSE

STAY QUIET [A], MATCHING UID

SELECT [A],

MATCHING UID

SELECT [A], MATCHING UID

ADDRESS MODE LEGEND:

[N] NONADDRESSED MODE

[A] ADDRESSED MODE

[S] SELECT MODE

RESET TO READY

[N,A], MATCHING UID

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Wait Times

ISO 15693 defines several standard wait times. For full

details, refer to ISO 15693-2, Section 9.

The wait time from request frame EOF to response

frame SOF is t1. t1 min is 318.6µs (4320 cycles), t1 nom

is 320.9µs (4352 cycles), and t1 max is 323.3µs (4384

cycles). Commands that perform MAC calculations or

write memory will extend t1 by a command specific combi-

nation of tRFAIP, tCSHA, and tPROG. If a 100% modulation

pulse is detected during t1, the transponder must restart

its t1 counter.

The 10% modulation ignore time after a request frame

EOF is received is tMIT. tMIT min is 323.3µs (4384 cycles)

+ tNRT, where tNRT is the nominal response frame length.

The wait time between a response frame and a subse-

quent request frame is t2. t2 min is 309.2µs (4192 cycles).

The wait time between slot EOFs in an Inventory com-

mand where Nb_slots_flag is t3. For 100% modulation,

t3MIN is 323.3µs (4384 cycles) + tSOF, where tSOF is the

time requires to transmit a request frame SOF. For 10%

modulation, t3 min is 323.3µs (4384 cycles) + tNRT +

t2MIN, where tNRT is the nominal response frame length.

Network Function Commands

The ISO 15693 standard defines four network function

commands: Inventory, Stay Quiet, Select, and Reset to

Ready. Their purpose is to identify the UIDs of all tran-

sponders in the field (to Inventory) and to manage access

to these transponders. Figure 20 shows how the network

function commands are used to transition a transponder

from one state to another.

Network Function Command Errors

Various error conditions can occur. If an error occurs, and

the request is sent in addressed mode with matching UID

or in select mode with the transponder in the Selected

state, the transponder will transmit an error response. In

any other mode/state combination, an error will result in

no response. In case of an error response, the response

begins with response flags of 01h, followed by a single-

byte error code. Table 5 shows a matrix of commands,

errors, and error codes.

Table 5. Network Function Command

Error Code Matrix

ERROR EXPLANATION

Invalid Request Packet

Option Flag Set

ERROR CODE 02h 03h

FAILING COMMAND

Reset to Ready ü ü

Select ü ü

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Detailed Command Descriptions

Inventory

This command allows the reader to learn the UIDs and

DSFIDs of all transponders in its RF field in an iterative

process.

The AFI_flag determines if the AFI byte must be included

in the request frame. The AFI byte is compared to the

transponders AFI. The parameter byte determines the

length of the mask. The LSb of the mask aligns with the

LSb of the transponder’s UID. The mask is compared to

the transponder’s UID. The Nb_slots_flag determines if

a slot counter is concantenated with the mask for com-

parison to the transponder’s UID. The slot counter starts

at 0000b after the Inventory request frame is transmitted,

and increments during the course of the Inventory com-

mand with every subsequent EOF sent by the reader. The

AFI byte (if used) must match the transponder’s AFI or be

00h, and the mask concatenated with the slot counter (if

used) must match the transponder’s UID for a response to

be generated. This allows the reader to select transpon-

ders to respond to the Inventory command. The process-

ing of an Inventory command ends if the transponder

receives an SOF of a new request frame.

If a transponder meets all conditions to respond, it trans-

mits a response frame. If multiple transponders meet the

conditions, the response frames collide and may not be

readable. The reader must eliminate the collision.

To identify all transponders in the RF field, the reader

could begin with a mask length of 0 and activate the

slot counter (Nb_slots_flag = 0). By using this method

and going through all 16 slots, the reader has a chance

to receive clean responses (i.e., the transponder is

identified) as well as colliding responses. To prevent a

transponder that has been identified from further partici-

pating in the collision management sequence, the reader

transitions it to the quiet state. Next, the reader issues

another Inventory command where the slot number that

previously generated a collision is now used as a 4-bit

mask, and runs again through all 16 slots. If a collision

is found, another Inventory command is issued, this time

with a mask that is extended at the higher bits by the slot

counter value that produced the collision. This process

is repeated until all transponders are identified. For a full

description of the Inventory command processing by the

transponder and the timing specifications, refer to ISO

15693 Part 3, Sections 8 to 9.

Inventory

Command Code 01h

Parameter Byte Mask Length (Table 6)

Conditions, Restrictions The command is ignored unless the transponder is in the Ready or Selected state.

Protocol Variations

• Nb_slot_ag = 0, AFI_ag = 0, mask length = 0

• Nb_slot_ag = 0, AFI_ag = 0, mask length ≠ 0

• Nb_slot_ag = 0, AFI_ag = 1, mask length = 0

• Nb_slot_ag = 0, AFI_ag = 1, mask length ≠ 0

• Nb_slot_ag = 1, AFI_ag = 0, mask length = 0

• Nb_slot_ag = 1, AFI_ag = 0, mask length ≠ 0

• Nb_slot_ag = 1, AFI_ag = 1, mask length = 0

• Nb_slot_ag = 1, AFI_ag = 1, mask length ≠ 0

Other Notes

For the setting of the request ags (RQF), see Table 4.

The mask pattern is transmitted only if the mask length is ≠ 0.

The AFI is transmitted only if the AFI_ag bit in the request ags is set to 1.

Error Conditions

(Error Response) An error will result in no response.

t1 (Request Frame to

Response Frame Delay) 318.6µs to 323.3µs

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Bits [7:0]: Mask Length (MLEN). These bits specify the length of the mask. The mask (MASK) is transmitted only if

MLEN is ≠ 0. The maximum mask length is 60 (3Ch, if Nb_slots_flag = 0) or 64 (40h, if Nb_slots_flag = 1).

Stay Quiet

This command addresses an individual transponder and transitions it to the Quiet state. The transponder does not send

a response.

Select

This command addresses an individual transponder and transitions it to the Selected state. The transponder transitioning

to the Selected state sends a response. If there was a transponder with a different UID in the Selected state, then that

transponder transitions to the Ready state without sending a response.

Table 6. Parameter Byte Bitmap

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

MLEN

Stay Quiet

Command Code 02h

Parameter Byte N/A

Conditions, Restrictions To transition to the Quiet state, the request must be sent in addressed mode with matching UID.

Protocol Variations None

Other Notes For the setting of the request ags (RQF), see Table 3.

Error Conditions

(Error Response) An error will result in no response.

t1 (Request Frame to

Response Frame Delay) None

Select

Command Code 25h

Parameter Byte N/A

Conditions, Restrictions To transition to the Selected state, the request must be sent in addressed mode with matching UID.

Protocol Variations None

Other Notes For the setting of the request ags (RQF), see Table 3.

Error Conditions

(Error Response)

• Request data format error (response error code = 02h)

• The Option_ag is set (response error code = 03h)

t1 (Request Frame to

Response Frame Delay) 318.6µs to 323.3µs

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Reset to Ready

This command addresses an individual transponder and transitions it to the Ready state. The transponder transitioning

to the Ready state sends a response.

Reset to Ready

Command Code 26h

Parameter Byte N/A

Conditions, Restrictions

To transition from the Quiet state to the Ready state, the request must be sent in nonaddressed mode

or in addressed mode with matching UID. To transition from the Selected state to the Ready state, the

request must be sent in select mode.

Protocol Variations • If the transponder is in the Selected state, and the request is sent in addressed mode with

nonmatching UID, the transponder transitions to the Ready state, but will not respond.

Other Notes For the setting of the request ags (RQF), see Table 3.

Error Conditions

(Error Response)

• Request data format error (response error code = 02h)

• The Option_ag is set (response error code = 03h)

t1 (Request Frame to

Response Frame Delay) 318.6µs to 323.3µs

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+Denotes a lead(Pb)-free/RoHS-compliant package.

T = Tape and reel.

†Contact factory for further details.

PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.

8 SO (150 mils) S8+2 21-0041 90-0096

10 TDFN (3mm x 4mm) T1034N+1 21-0268 90-0247

Wafer — — —

PART TEMP RANGE PIN-PACKAGE

MAX66240ESA+ -40°C to +85°C 8 SO

MAX66240ESA+T -40°C to +85°C8 SO

(2.5k pcs)

MAX66240ETB+ -40°C to +85°C10 TDFN

MAX66240ETB+T -40°C to +85°C10 TDFN

(2.5k pcs)

MAX66240E/W+† -40°C to +85°C

AU bumped,

tested, diced

wafer

MAX66240/W+† -40°C to +85°C Tested wafer

Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses

are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time. The parametric values (min and max limits)

shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.

Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.

MAX66240 DeepCover Secure Authenticator with

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Package Information

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.

Ordering Information

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.

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