Datasheet

ManualsBrandsMaxim ManualsDigitalTemperature sensor SO-8

1 of 17 021907

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 E

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 DESCRIPTION

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

- Digital Power Supply (+3V - +5V)

NC - No Connection

DESCRIPTION

The DS1624 consists of a digital thermometer and 256 bytes of E

memory. The thermometer provides

13-bit temperature readings which indicate the temperature of the device. The E

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

www.maxim-ic.com

SDA

GND

DS1624S 8-PIN SOIC (208 MIL)

SDA

GND

DS1624 8-PIN DIP (300 MIL)

Summary of content (17 pages)

PAGE 1
DS1624 Digital Thermometer and Memory www.maxim-ic.com FEATURES PIN ASSIGNMENT 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.
PAGE 2
DS1624 ORDERING INFORMATION ORDERING INFORMATIO N DS1624 DS1624+ DS1624S DS1624S+ DS1624S/T&R DS1624S+T&R PACKAGE MARKING DS1624 DS1624 (See Note) DS1624S DS1624S (See Note) DS1624S DS1624S (See Note) DESCRIPTION DS1624 in 300 mil 8-pin DIP DS1624 in Lead-Free 300 mil 8-pin DIP DS1624 in 208 mil 8-pin SO DS1624 in Lead-Free 208 mil 8-pin SO DS1624 in 208 mil 8-pin SO, 2000 Piece Tape-and-Reel DS1624 in Lead-Free 208 mil 8-pin SO, 2000 Piece Tapeand-Reel Note: A “+” symbol will also be marked on the pac
PAGE 3
DS1624 DS1624 FUNCTIONAL BLOCK DIAGRAM Figure 1 STATUS REGISTER & CONTROL LOGIC VDD SCL TEMPERATURE SENSOR ADDRESS AND I/O CONTROL SDA EEPROM MEMORY (256 BYTES) A0 A1 A2 GND 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 controls the message is called a “master”.
PAGE 4
DS1624 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.
PAGE 5
DS1624 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 clock are received through SDA and SCL. After each byte is received an acknowledge bit is transmitted.
PAGE 6
DS1624 OPERATION-MEASURING TEMPERATURE 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.
PAGE 7
DS1624 TEMPERATURE MEASURING CIRCUITRY Figure 4 SLOPE ACCUMULATOR PRESET COMPARE LOW TEMPERATURE COEFFICIENT OSCILLATOR COUNTER PRESET SET/CLEAR LSB INC TEMPERATURE REGISTER =0 HIGH TEMPERATURE COEFFICIENT OSCILLATOR COUNTER STOP =0 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.
PAGE 8
DS1624 Temperature is represented in the DS1624 in terms of a 0.03125°C LSB, yielding the following 13–bit format: MSB 0 LSB 0 0 1 1 0 0 1 0 0 0 1 0 0 0 0 = +25.0625°C OPERATION 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.
PAGE 9
DS1624 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 device code, the 3–bit slave address, and the R/ W 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 acknowledge pulse to the master during the ninth clock pulse.
PAGE 10
DS1624 Access 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 Config [ACh] If R/ W 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.
PAGE 11
DS1624 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 FUNCTION EXAMPLE BUS MASTER DS1624 DATA (MSB COMMENTS MODE MODE FIRST) {Command protocol for configuration register} {Start here} TX RX START Bus Master Initiates a Start condition. TX RX Bus Master sends DS1624 address; R/ W =”0”; RX TX ACK DS1624 generates acknowledge bit.
PAGE 12
DS1624 BUS MASTER MODE TX DS1624 MODE RX DATA (MSB FIRST) NACK TX RX STOP {Command protocol for writing to EEPROM} {Start here} TX RX START TX RX COMMENTS NOTES Bus Master sends “NO ACKNOWLEDGE” bit. Bus Master initiates the STOP condition. Bus Master initiates a Start condition. Bus Master sends DS1624 address; R/ W =0; RX TX ACK DS1624 generates acknowledge bit. TX RX 17h Bus Master sends Access Memory command protocol. RX TX ACK DS1624 generates acknowledge bit.
PAGE 13
DS1624 BUS MASTER MODE RX TX . . . . RX TX DS1624 MODE TX RX . . . . TX RX DATA (MSB FIRST) ACK . . . . NACK TX RX STOP COMMENTS DS1624 sends the second byte of data. Bus Master generates acknowledge bit. . . . . DS1624 sends the n-th byte of data. Bus Master send “NO KWOWLEDGE” bit. Bus Master initiates the STOP condition. NOTES 5 NOTES: 1. If this protocol follows a write and the DS1624 does not acknowledge here, restart the protocol at the Start here.
PAGE 14
DS1624 ABSOLUTE MAXIMUM RATINGS* Voltage on Any Pin Relative to Ground Operating Temperature Storage Temperature Soldering Temperature –0.5V to +7.0V –55°C to +125°C –55°C to +125°C 260°C for 10 seconds * This is a stress rating only and functional operation of the device at these or any 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.
PAGE 15
DS1624 AC ELECTRICAL CHARACTERISTICS PARAMETERS Temperature Conversion Time NV Write Cycle Time EEPROM Writes EEPROM Data Retention SLK Clock Frequency Bus Free Time Between a STOP and START Condition Hold Time (Repeated) START Condition Low Period of SCL Clock High Period of SCL Clock Setup Time for a Repeated START Condition Data Hold Time Data Setup Time SYMBOL TTC CONDITION tWR (-55°C to +125°C; VDD=2.7V to 5.
PAGE 16
DS1624 AC ELECTRICAL CHARACTERISTICS PARAMETER Input Capacitance SYMBOL CI (-55°C to +125°C; VDD=2.7V to 5.5V) MIN TYP 5 MAX UNITS pF NOTES 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.
PAGE 17
DS1624 TIMING DIAGRAM tSP Note: The DS1624 does not delay the SDA line internally with respect to SCL for any length of time TYPICAL PERFORMANCE CURVE DS1624 DIGITAL THERMOMETER AND THERMOSTAT TEMPERATURE READING ERROR TEMPERATURE (deg.