DS1624S+T&R - Hytronics

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FEATURES

 Temperature measurements require no

external components

 Measures temperatures from -55°C to +125°C

in 0.03125°C increments. Fahrenheit

equivalent is -67°F to +257°F in 0.05625°F

increments

 Temperature is read as a 13-bit value (two

byte transfer)

 Converts temperature to digital word in 1

second (max)

 256 bytes of E2 memory on board for storing

information such as frequency compensation

coefficients

 Data is read from/written via a 2-wire serial

interface (open drain I/O lines)

 Applications include temperature-

compensated crystal oscillators for test

equipment and radio systems

 8-pin DIP or SOIC packages

PIN ASSIGNMENT

PIN DES CRIPTION

SDA - 2-Wire Serial Data Input/Output

SCL - 2-Wire Serial Clock

GND - Ground

A0 - Chip Address Input

A1 - Chip Address Input

A2 - Chip Address Input

VDD - Power Supply (+2.7V to +5.5V)

NC - No Connection

DESCRIPTION

The DS1624 consists of a digital thermometer and 256 bytes of E2 memory. The thermometer provides

13-bit temperature readings which indicate the temperature of the devic e. The E2 memory allows a user to

store frequency compensation coefficients for digital correction of crystal frequency due to temperature.

Any other type of information may also reside in this user space.

DS1624

Digital Thermometer and Memory

19-6288; Rev 5/12

www.maxim-ic.com

SDA

SCL

GND

VDD

DS1624S 8-PIN SOIC (208 MIL)

SDA

SCL

GND

VDD

DS1624 8-PIN PDIP (30 0 MIL)

DS1624

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ORDERING INFORMATION

ORDERING

INFORMATION

PACKAGE

MARKING

DESCRIPTION

DS1624+

DS1624

DS1624 in Lead-Free 300 mil 8-pin DIP

DS1624S+

DS1624S

DS1624 in Lead-Free 208 mil 8-pin SO

DS1624S+T&R

DS1624S

DS1624 in Lead-Free 208 mil 8-pin SO, 2000 Piece Tape-

and-Reel

A “+” symbol will also be marked on the package near the Pin 1 indicator.

DET AILED PIN DE S CRIPTIO N Ta ble 1

SYMBOL

DESCRIPTION

SDA

Data input/output pin for 2-wire serial communication port.

SCL

Clock input/output pin for 2-wire serial communication port.

No connect. No Internal Connection.

GND

Ground pin.

Address input pin.

VDD

Supply Voltage 2.7V to 5.5V input power pin.

OVERVIEW

A block diagram of the DS1624 is shown in Figure 1. The DS1624 consists of two separate functional

units: 1) a 256–byte nonvolatile E2 memory, and 2) a direct–to–digital temperature sensor.

The nonvolatile memory is made up of 256 bytes of E2 memory. This memory may be used to store any

type of information the user wishes; for example, frequency compensation coefficients may be placed in

this memory to allow for compensation of measured frequency depending upon the temperature at which

the measurement is made. These memory locations are accessed through the 2–wire serial bus.

The direct to digital temperature sensor allows the DS1624 to measure the ambient temperature and

report the temperature value in a 13–bit word, wit h 0.03125°C resolution. The temperature sensor and i ts

related registers are accessed through the 2–wire serial interface.

DS1624

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DS1624 FUNCTIONAL BLOCK DIAGR AM Figure 1

2-WIRE SERIAL DATA BUS

The DS1624 supports a bi–directional two–wire bus and data transmission protocol. A device that sends

data onto the bus is defined as a transmitter, and a device receiving data as a receiver. The device that

control s the mes sage is called a “m aster”. The de vices t hat are cont roll ed b y the m aster are “slaves ”. The

bus must be controlled by a master device which generates the serial clock (SCL), controls the bus access,

and generates the START and STOP conditions. The DS1624 operates as a slave on the two–wire bus.

Connections to the bus are made via the open–drain I/O lines SDA and SCL. The following bus protocol

has been defined (See Figure 2):

• Data transfer may be initiated only when the bus is not busy.

• During data transfer, the data line must remain stable whenever the clock line is HIGH. Changes in

the data line while the clock line is high will be interpreted as control signals.

Accordingly, the following bus conditions have been defined:

Bus not busy: Both data and clock lines remain HIGH.

Start data transfer: A change in the state of the data line, from HIGH to LOW, while the clock is HIGH,

defines a START condition.

Stop data transfer: A change in the state of the data line, from LOW to HIGH, while the clock line is

HIGH, defines the STOP condition.

STATU S RE G ISTE R &

CONTROL LOGIC

TEMPERATURE SENSOR

EEPROM MEMORY (256 BYTES)

ADDRESS

AND

I/O CONTROL

VDD

SCL

SDA

GND

DS1624

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Data valid: The state of the data line represents valid data when, after a START condition, the data line

is stable for the duration of the HIGH period of the clock signal. The data on the line must be changed

during the LOW period of the clock signal. There is one clock pulse per bit of data.

Each data transfer is initiated with a START condition and terminated with a STOP condition The

number of data bytes transferred between START and STOP conditions is not limited, and is determined

by the master device. The information is transferred byte–wise and each receiver acknowledges with a

ninth bit.

Within the bus specifications a regular mode (100 KHz clock rate) and a fast mode (400 KHz clock rate)

are defined. The DS1624 works in both modes.

Acknowledge: Each receiving device, when addressed, is obliged to generate an acknowledge after the

reception of each byte. The master device must generate an extra clock pulse which is associated with this

acknowledge bit.

A device that acknowledges must pull down the SDA line during the acknowledge clock pulse in such a

way that the SDA line is stable LOW during the HIGH period of the acknowledge related clock pulse. Of

course, setup and hold times must be taken into account. A master must signal an end of data to the slave

by not generating an acknowledge bit on the last byte that has been clocked out of the sl ave. In thi s case,

the slave must leave the data line HIGH to enable the master to generate the STOP condition.

DATA TRANSFER ON 2-WIRE SERIAL BUS Figure 2

Figure 2 details how data transfer is accomplished on the two–wire bus. Depending upon the state of the

bit, two types of data transfer are possible:

1. Data transfer from a master transmitter to a slave receiver. The first byte transmitted by the

master is the slave address. Next follows a number of data bytes. The slave returns an acknowledge

bit after each received byte.

2. Data transfer from a slave transmitter to a master receiver. The first byte (the slave

address) is transmitted by the master. The slave then returns an acknowledge bit. Next follows a

number of data bytes transmitted by the slave to the master. The master returns an acknowledge bit

DS1624

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after all received bytes other than the last byte. At the end of the last received byte, a ‘not

acknowledge’ is returned.

The master device generates all of the serial clock pulses and the START and STOP conditions. A

transfer is ended with a STOP condition or with a repeated START condition. Since a repeated START

condition is also the beginning of the next serial transfer, the bus will not be released.

The DS1624 may operate in the following two modes:

1. Slave receiver mode: Serial data and cl ock a re recei ved thr ough S DA an d SC L. After each byte i s

received an acknowledge bit is transmitted. START and STOP conditions are recognized as the

beginning and end of a serial transfer. Address recognition is performed by hardware after reception

of the slave address and direction bit.

2. Slave transmitter mode: The first byte is received and handled as in the slave receiver mode.

However, in this mode the direction bit will indicate that the transfer d irectio n is reversed . Serial d ata

is transmitted on SDA by the DS1624 while the serial clock is input on SCL. START and STOP

conditions are recognized as the beginning and end of a serial transfer.

SLAVE ADDRESS

A control byte is the first byte received following the START condition from the master device. The

control byte consists of a four bit control code; for the DS1624, this is set as 1001 binary for read and

write operations. The next three bits of the control byte are the device s elect bits (A2, A1, A0). They are

used b y t he master d evice to s elect which o f eight dev ices are to be accessed . These bits a re in effe ct the

three least significant bits of the slave address. The last bit of the control byte (R/

) defines the

operation to be performed. When set to a “1”, a read operation is selected, when set to a “0”, a write

operation is selected. Following the START condition the DS1624 monitors the SDA bus checking the

device type identifier being transmitted. Upon receiving the 1001 code and appropriate device select bits,

the slave device outputs an acknowledge signal on the SDA line.

2-WIRE SERIAL COMMUNIC ATION WI TH DS 1 6 2 4 Figure 3

DS1624

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OPERATION-ME ASURING TEM P E RATURE

A block diagram of the DS1624 is shown in Figure 1. The DS1624 measures temperatures through the

use of an on–board proprietary temperature measurement technique. A block diagram of the temperature

measurement circuitry is shown in Figure 4.

The DS1624 measures temperature by counting the number of clock cycles that an oscillator with a low

temperature coefficient goes through during a gate period determined by a high temperature coefficient

oscillator. The counter is preset with a base count that corresponds to –55°C. If the counter reaches zero

before the gate period is over the temperature register, which is also preset to the –55°C value, is

incremented indicating that the temperature is higher than –55°C.

At the same time, the counter is preset with a value determined by the slope accumulator circuitry. This

circuitry is needed to compensate for the parabolic behavior of the oscillators over temperature. The

counter is then clocked again until it reaches zero. If the gate period is still not finished, then this process

repeats.

The slope accumulator is used to compensate for the nonlinear behavior of the oscillators over

temperature, yielding a high resolution temperature measurement. This is done by changing the number

of counts necessary for the counter to go through for each incremental degree in temperature. To obtain

the desired resolution, both the value of the counter and the number of counts per °C (the value of the

slope accumulator) at a given temperature must be known.

DS1624

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TEMPE RATURE MEASURING CI RCUITRY Figure 4

Internally, this calculation is performed by the DS1624 to provide 0.03125°C resolution. The temperature

reading is provided in a 13–bit, two’s complement reading by issuing READ TEMPERATURE

command. Table 2 describes the exact relationship of output data to measured temperature. The data is

transmitted serially through the 2–wire serial interface, MSB fi rst. The DS 1624 can measu re temperatur e

over the range of -55°C to +125°C in 0.03125°C increments. For Fahrenheit usage a lookup table or

conversion factor must be used.

TEMPE RATURE/DATA RELATIONSHIP S Table 2

TEMP

DIGITAL OUTPUT

(Binary)

DIGITAL OUTPUT

(Hex)

+125˚C

01111101 00000000

7D00h

+25.0625˚C

00011001 00010000

1910h

+½˚C

00000000 10000000

0080h

0˚C

00000000 00000000

0000h

-½˚C

11111111 10000000

FF80h

-25.0625˚C

11100110 11110000

E6F0h

-55˚C

11001001 00000000

C900h

Since data is transmitted over the 2–wire bus MSB first, temperature data may be written to/read fr om the

DS1624 as either a single byte (with temperature resolution of 1°C) or as two bytes, the second byte

containing the value of the 5 least significant bits of the temperature reading as shown in Table 1. Note

that the remaining three bits of this byte are set to all 0’s.

SLOPE AC CUMUL ATOR

PRESET

COMPARE

LOW TEMPERATURE

COEFFICIENT OSCILLATOR

COUNTER

PRESET

TEMPERATURE REGISTER

HIGH TEMPERATURE

COEFFICIENT OSCILLATOR

COUNTER

INC

STOP

SET/CLEAR

LSB

DS1624

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Temperature is represented in the DS1624 in terms of a 0.03125°C LSB, yielding the following 13–bit

format:

OPER ATION AND CONTROL

A configuration/status register is used to determine the method of operation of the DS1624 will use in a

particular application as well as indicating the status of the temperature conversion operation.

The configuration register is defined as follows:

CONFIGURATION/STATUS REGISTER

where

DONE = Conversion Done bit. “1” = Conversion complete, “0” = conversion in progress.

1SHOT = One Shot Mode. If 1SHOT is “1”, the DS1624 will perform one temperature conversion upon

receipt of the Start Convert T protocol. If 1SHOT is “0”, the DS1624 will continuously perform

temperature conversions. This bit is nonvolatile and the DS1624 is shipped with 1SHOT = “0”.

Since the configuration register is implemented in E2, writes to the register require 10 ms to complete.

After issuing a command to write to the configuration register, no further accesses to the DS1624 should

be made for at least 10 ms.

OPERATION – MEMORY

BYTE PROGRAM MODE

In this mode, the master sends addresses and one data byte to the DS1624.

Following a START condition, the device code (4–bit), the slave address (3 bit), and the R/

bit, which

is lo gic LOW, are plac ed ont o t he b us b y the m aster. T he mast er then send s the Access Memor y protocol.

This indicates to the addressed DS1624 that a byte with a word address will follow after it has generated

an acknowledge bit. Therefore, the next byte transmitted by the master is the word address and will be

written into the address pointer of the DS1624. After receiving the acknowledge of the DS1624, the

master device transmits the data word to be written into the addressed memory location. The DS1624

acknowledges again and the master generates a STOP condition. This initiates the internal programming

cycle of the DS1624. A repeated START condition, instead of a STOP condition, will abort the

programming operation.

During the programming cycle the DS1624 will not acknowledge any further accesses to the device until

the programming cycle is complete (approximately 10 ms.)

LSB

= +25.0625°C

MSB

DONE

1SHOT

DS1624

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PAGE PROGRAM MODE

To program the DS1624 the master sends addresses and data to the DS1624 which is the slave. This is

done by supplying a START condition followed by the 4–bit devi ce code, t he 3–bit slave address, and the

bit which is defined as a logic LOW for a write. The master then sends the Access Memory

protocol. This indicates to the addressed slave that a word address will follow. The slave outputs the

acknowled ge pulse to the master during the ninth clock pulse. When the word address is received by the

DS1624 it is placed in the address pointer definin g which memory location is to be w ritten. The DS1624

will gener at e an ack no wl ed ge aft e r every 8–bits received and store th em consecu ti vely in an 8–byte RAM

until a STOP condition is detected which initiates the internal programming cycle.

A repeated START condition, instead of a STOP condition, will abort the programming operation.

During the programming cycle the DS1624 will not acknowledge any further accesses to the device until

the programming cycle is complete (approximately 10 ms).

If more than 8 bytes are transmitted by the master the DS1624 will roll over and overwrite the data

beginning with the first received b yt e. This does n ot affect erase/ write cycles of the EEPROM array and

is accomplished as a result of only allowing the address register’s bottom 3 bits to increment while the

upper 5 bits remain unchanged. The DS1624 is capable of 50,000 writes (25,000 erase/write cycles)

before EEPROM wear out may occur.

If the master generates a STOP condition after transmitting the first data word, byte programming mode

is entered.

READ MODE

In this mode, the master is reading data from the DS1624 E2 memory. The master first provides the slave

address to the device with R/

set to “0”. T he master th en sends t he Access Memo ry protocol an d, after

receiving an acknowledge, then provides the word address, which is the address of the memory location

at which it wishes to begin reading. Note that while this is a read operation the address pointer must first

be written. During this period the DS1624 generates acknowledge bits as defined in the appropriate

section.

The mast er now generate s another S TART condition and transmits the slave address. This time the R/

bit is set to “1” to put the DS1624 in read mode. After the DS1624 generates the acknowledge bit it

outputs the data from the addressed location on the SDA pin, increments the address pointer, and, if it

receives an acknowledge from the master, transmits the next consecutive byte. This auto-increment

sequence is only aborted when the master sends a STOP condition instead of an acknowledge. When the

address pointer reaches the end of the 256–byte memory space (address FFh) it will increment from the

end of the memory back to the first location of the memory (address 00h).

COMMAND SET

Data and control information is read from and written to the DS1624 in the format shown i n Figure 3. To

write to the DS1624, the master will issue the slave address of the DS1624 and the R/

bit will be set to

“0”. After receiving an acknowledge the bus master provides a command protocol. After receiving this

protocol the DS1624 will issue an acknowledge then the master may send data to the DS1624. If the

DS1624 is to be read, the master must send the command protocol as before then issue a repeated START

condition and the control byte again, this time with the R/

bit set to “1” to allow reading of the data

from the DS1624. The command set for the DS1624 as shown in Table 3 is as follows:

DS1624

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A ccess Memory [17h]

This command instructs the DS1624 to access its E2 memory. After issuing this command, the next data

byte is the value of the word address to be accessed. See OPERATION–MEMORY section for detailed

explanations of the use of this protocol and data format following it.

Access Confi g [ACh]

If R/

is “0”, this command writes to the configuration register. After issuing this command, the next

data byte is the value to be written into the configuration register. If R/

is “1”, the next data byte read is

the value stored in the configuration register.

Read Temperat ure [ AAh]

This command reads the last temperature conversion result. The DS1624 will send two bytes in the

format described earlier, which are the contents of this register.

Star t Conver t T [ EEh]

This command begins a temperature conversion. No further data is required. In one–shot mode the

temperature conversion will be performed and then the DS1624 will remain idle. In continuous mode this

command will initiate continuous conversions.

Stop Convert T [ 22h]

This command stops temperature conversion. No further data is required. This command may be used to

halt a DS1624 in continuous conversion mode. After issuing this command, the current temperature

measurement will be completed then the DS1624 will remain idle until a Start Convert T is issued to

resume continuous operation.

DS1624 COMMAND SET Table 3

INSTRUCTION

DESCRIPTION

PROTOCOL

2-WIRE BUS

DATA AFTER

ISSUING

PROTOCOL

NOTES

TEMPERATURE CONVERSION COMMANDS

Read

Temperature

Reads last converted temperature

value from temperature register.

AAh

<read 2 bytes

data>

Start Convert T

Initiates temperature conversion.

EEh

idle

Stop Convert T

Halts temperature conversion.

22h

idle

THERMOSTAT COMMANDS

Access Memory

Reads or writes to 256-byte

EEPROM memory.

17h

Access Config

Reads or writes configuration data

to configuration register.

ACh

NOTES:

1. In continuous conversion mode a Stop Convert T command will halt continuous conversion. To

restart, the Start Convert T command must be issued. In one–shot mode a Start Convert T command

must be issued for every temperature reading desired.

2. Writing to the E2 typically requires 10 ms at room temperature. After issuing a write command, no

further reads or writes should be requested for at least 10 ms.

DS1624

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During the programming cycle the DS1624 will not acknowledge any further accesses to the device until

the programming cycle is complete (approximately 10 ms).

MEMORY FUNCTI O N E XAMPLE

BUS MASTER

MODE

DS1624

MODE

DATA (MSB

FIRST)

COMMENTS

NOTES

{Command protocol for configuration register}

{Start here}

START

Bus Master Initiates a Start condition.

<cadr,0>

Bus Master sends DS1624 address;

=”0”;

ACK

DS1624 generates acknowledge bit.

ACh

Bus Master sends Access Config

command protocol.

ACK

DS1624 generates acknowledge bit.

00h

Bus Master sets up DS1624 for continuous

conversion.

ACK

DS1624 generates acknowledge bit.

2, 4

STOP

Bus Master initiates the STOP condition.

{Command protocol for Start Convert T}

{Start here}

START

Bus Master initiates a Start condition.

<cadr,0>

Bus Master sends DS1624 address;

=0;

ACK

DS1624 generates acknowledge bit.

EEh

Bus Master sends Start Convert T

command protocol.

ACK

DS1624 generates acknowledge bit.

STOP

Bus Master initiates the STOP condition.

{Command protocol for reading the Temperature}

{Start here}

START

Bus Master initiates a Start condition.

<cadr,0>

Bus Master sends DS1624 address;

=0;

ACK

DS1624 generates acknowledge bit.

AAh

Bus Master sends Read Temp command

protocol.

ACK

DS1624 generates acknowledge bit.

START

Bus Master initiates a Repeated Start

condition.

<cadr,1>

Bus Master sends DS1624 address;

=1;

ACK

DS1624 generates acknowledge bit.

<data>

DS1624 sends the MSB byte of

Temperature.

ACK

Bus Master generates acknowledge bit.

DS1624

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<data>

DS1624 sends the LSB byte of

Temperature.

BUS MASTER

MODE

DS1624

MODE

DATA (MSB

FIRST)

COMMENTS

NOTES

NACK

Bus Master sends “NO

ACKNOWLEDGE” bit.

STOP

Bus Master initiates the STOP condition.

{Command protocol for writing to EEPROM}

{Start here}

START

Bus Master initiates a Start condition.

<cadr,0>

Bus Master sends DS1624 address;

=0;

ACK

DS1624 generates acknowledge bit.

17h

Bus Master sends Access Memory

command protocol.

ACK

DS1624 generates acknowledge bit.

<madr>

Bus Master sets the starting memory

address.

ACK

DS1624 generates acknowledge bit.

<data>

Bus Master sends the first byte of data.

ACK

DS1624 generates acknowledge bit.

<data>

Bus Master sends the second byte of data.

ACK

DS1624 generates acknowledge bit.

<data>

Bus Master sends the n-th byte of data.

ACK

DS1624 generates acknowledge bit.

STOP

Bus Master initiates the STOP condition.

2, 4

{Command protocol for reading from EEPROM}

{Start here}

START

Bus Master initiates a Start condition.

<cadr,0>

Bus Master sends DS1624 address;

=0;

ACK

DS1624 generates acknowledge bit.

17h

Bus Master sends Access Memory

command protocol.

ACK

DS1624 generates acknowledge bit.

<madr>

Bus Master sends the starting memory

address.

ACK

DS1624 generates acknowledge bit.

START

Bus Master initiates a Repeated Start

condition.

<cadr,1>

Bus Master sends DS1624 address;

=1;

ACK

DS1624 generates acknowledge bit.

DS1624

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<data>

DS1624 sends the first byte of data.

ACK

Bus Master generates acknowledge bit.

DS1624

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BUS MASTER

MODE

DS1624

MODE

DATA (MSB

FIRST)

COMMENTS

NOTES

<data>

DS1624 sends the second byte of data.

ACK

Bus Master generates acknowledge bit.

<data>

DS1624 sends the n-th byte of data.

NACK

Bus Master send “NO KWOWLEDGE”

bit.

STOP

Bus Master initiates the STOP condition.

NOTES:

1. If this protocol follows a write and the DS1624 does not acknowledge here, restart the protocol at the

Start here. If it does acknowledge, continue on.

2. Wait for write to complete (10 ms typ. 50 ms max). If DS1624 does not acknowledge the command

protocol immediately following a configure register or write mem protocol, the DS1624 has not

finished writing. Restart the new command protocol until the DS1624 acknowledges.

3. If n is greater than eight, the last eight bytes are the only bytes saved in memory. If the starting

address is 00 and the incoming data is 00 11 22 33 44 55 66 77 88 99, the result will be mem00=88

mem01=99 mem02=22 mem03=33 mem04=44 mem05=55 mem06=66 mem07=77. The data wraps

around and overwrites itself.

4. The STOP condition causes the DS1624 to initiate the write to EEPROM sequence. If a START

condition comes instead of the STOP condition, the write is aborted. The data is not saved.

5. For reading, the address is incremented. If the starting address is 04h and 30 bytes of data are read

out, 21h is the final address read.

DS1624

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ABSOLUT E MAXIMUM RA T INGS*

Voltage on Any Pin Relative to Ground ............................................................................... -0.5V to +6.0V

Operating Temperature Range ........................................................................................... -55°C to +125°C

Storage Tem per at ure Range .............................................................................................. -55°C to +125°C

Soldering Temperature (reflow) ....................................................................................................... +260°C

Lead Temperature (soldering, 10s) ................................................................................................... +300°C

* This is a stress rating onl y and functional operation of the device at these or an y other conditions above

those indicated in the operation sections of this specification is not implied. Exposure to absolute

maximum rating conditions for extended periods of time may affect reliability.

RECOMME NDE D DC OPE RATING CONDITI O NS

PARAMETER

SYMBOL

MIN

TYP

MAX

UNITS

NOTES

Supply Voltage

VDD

2.7

5.0

5.5

DC ELECTRICAL CHARACTERIS TICS (-55°C to +125°C; VDD=2.7V to 5.5V)

PARAMETER

SYMBOL

CONDITION

MIN

TYP

MAX

UNITS

NOTES

Thermometer Error

ERR

0°C to 70°C

-55°C to +0°C

and +70°C to

+125°C

±½

°C

See Typical Curve

Low Level Input

Voltage

-0.5

0.3V

High Level Input

Voltage

0.7V

0.5

Pulse width of spikes

which must be

suppressed by the input

filter

Fast Mode

Low Level Output

Voltage

OL1

3 mA sink

current

0.4

OL2

6 mA sink

current

0.6

Input Current each I/O

0.4<V

I/O

<0.9VDD

-10

+10

µA

I/O Capacitance

CI/O

Active Supply Current

Temperature

Conversion

1000

E2 Write

400

µA

3, 4

Communica-

tion Only

100

Standby Supply Current

ISTBY

µA

3, 4

DS1624

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AC ELECTRICAL CHARACTERIS TICS (-55°C to +125°C; VDD=2.7V to 5.5V)

PARAMETERS

SYMBOL

CONDITION

MIN

TYP

MAX

UNITS

NOTES

Temperature

Conversion Time

400

1000

NV Write Cycle

Time

0°C to 70°C

EEPROM Writes

NEEWR

-20°C to +70°C

50k

writes

EEPROM Data

Retention

EEDR

-20°C to +70°C

years

SLK Clock

Frequency

SCL

Fast Mode

Standard Mode

400

100

kHz

Bus Free Time

Between a

STOP and START

Condition

BUF

Fast Mode

Standard Mode

1.3

4.7

µs

Hold Time

(Repeated)

START Condition

HD:STA

Fast Mode

Standard Mode

0.6

4.0

µs

Low Period of

SCL Clock

LOW

Fast Mode

Standard Mode

1.3

4.7

µs

High Period of

SCL Clock

HIGH

Fast Mode

Standard Mode

0.6

4.0

µs

Setup Time for a

Repeated

START Condition

SU:STA

Fast Mode

Standard Mode

0.6

4.7

µs

Data Hold Time

HD:DAT

Fast Mode

Standard Mode

0.9

µs

Data Setup Time

SU:DAT

Fast Mode

Standard Mode

100

250

Rise Time of both

SDA and

SCL Signals

Fast Mode

Standard Mode

20+0.1C

300

1000

Fall Time of both

SDA and

SCL Signals

Fast Mode

Standard Mode

20+0.1C

300

Setup Time for

STOP

Condition

SU:STO

Fast Mode

Standard Mode

0.6

4.0

µs

Capacit iv e Load

for each Bus

Line

400

All values referred to VIH=0.9 VDD and VIL=0.1 VDD.

DS1624

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AC ELECTRICAL CHARACTERIS TICS (-55°C to +125°C; VDD=2.7V to 5.5V)

PARAMETER

SYMBOL

MIN

TYP

MAX

UNITS

NOTES

Input Capacitance

NOTES:

1. All voltages are referenced to ground.

2. I/O pins of fast mode devices must not obstruct the SDA and SCL lines if VDD is switched off.

3. ICC specified with SDA pin open.

4. ICC specified with VCC at 5.0V and SDA, SCL = 5.0V, 0°C to 70°C.

5. After this period, the first clock pulse is generated.

6. The maximum tHD:DAT has onl y to be met if the device does not stretch the LOW period (tLOW) of the

SCL signal.

7. A fast mode device can be used in a standard mode system, but the requirement tSU:DAT >250 ns must

then be m et. This will aut omaticall y b e the cas e if the devi ce does n ot stret ch the LOW period o f the

SCL signal. If such a device does stretch the LOW period of the SCL signal, it must output the next

data bit to the SDA line tRMAX+tSU:DAT = 1000+250 = 1250 ns before the SCL line is released.

8. Cb – total capacitance of one bus line in pF.

9. Writing to the nonvolatile memory should only take place in the 0°C to 70°C temperature range.

10. See Typical Curve for specification limits outside the 0°C to 70°C temperature range. Thermometer

error reflects sensor accuracy as tested during calibration.

DS1624

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TIMING DIAGRAM

Note: T he DS1624 do e s not delay the SDA line inte r nally with respe c t to SCL for any length of time

TYPICAL PERFORMANCE CURVE

DS1624 DIGITAL THERMOMETER AND THERMOSTAT

TEMPERATURE READING ERROR

TEMPERATURE (deg. C)

tSP

DS1624

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PACKAGE INFORMATION

For the latest pac kage outline infor mation and la nd patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-“

in the package code indicates RoHS status only. Package drawings may show a di fferent suffix character, but the drawing

pertains to the package regardless of RoHS status.

PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.

8 PDIP

P8+4

21-0043

—

8 SO W8+2 21-0262 90-0258

DS1624

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REVIS IO N HIS TO RY

REVISION

DATE

DESCRIPTION

PAGES

CHANGED

5/12 Updated ordering information, soldering, and package information

1, 2, 7, 14,