Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsDS75LVU+

General Description

The DS75LV low-voltage (1.7V to 3.7V) digital thermom-

eter and thermostat provides 9-, 10-, 11-, or 12-bit digital

temperature readings over a -55°C to +125°C range with

±2°C accuracy over a -25°C to +100°C range. At power-up,

the DS75LV defaults to 9-bit resolution for software com-

patibility with the LM75. Communication with the DS75LV

is achieved through a simple 2-wire serial interface.

The DS75LV thermostat has a dedicated open-drain out-

put (OS) and programmable fault tolerance, which allows

the user to define the number of consecutive error condi-

tions that must occur before OS is activated. There are two

thermostatic operating modes that control thermostat oper-

ation based on user-defined trip-points (T

and T

HYST

Applications

● Personal Computers

● Cellular Base Stations

● Ofce Equipment

● Any Thermally Sensitive System

Benets and Features

● Extend Performance Range with Low-Voltage,

1.7V to 3.7V Operating Range

● Maximize System Accuracy in Broad Range of

Thermal Management Applications

• Measures Temperature from -55°C to +125°C

(-67°F to +257°F)

• ±2°C Accuracy over a -25°C to 100°C Range

• User-Congurable Resolution from 9 Bits (Default)

to 12 Bits (0.5°C to 0.0625°C)

● Easy Upgrade to LM75: Pin and Software Compatible

● Simplify Distributed Temperature-Sensing

Applications with Multidrop Capability

• Up to Eight DS75LVs Can Operate on 2-Wire Bus

● Increase Reliability and System Robustness

• Internally Filtered Data Lines for Noise Immunity

(50ns Deglitch)

• Bus Timeout Feature Prevents Lockup on 2-Wire

Interface

● Minimize Power Consumption with Built-In Shutdown

Mode

● Flexible User-Defined Thermostatic Modes with

Programmable Fault Tolerance

19-7469; Rev 2; 12/14

DS75LV Digital Thermometer and Thermostat

Functional Block Diagram

TOS AND THYST

REGISTERS

CONFIGURATION

TEMPERATURE

OVERSAMPLING

MODULATOR

PRECISION

REFERENCE

DIGITAL

DECIMATOR

ADDRESS

AND

I/O CONTROL

SCL

SDA

GND

THERMOSTAT

COMPARATOR

DS75LV

Summary of content (14 pages)

PAGE 1
DS75LV Digital Thermometer and Thermostat General Description The DS75LV low-voltage (1.7V to 3.7V) digital thermometer and thermostat provides 9-, 10-, 11-, or 12-bit digital temperature readings over a -55°C to +125°C range with ±2°C accuracy over a -25°C to +100°C range. At power-up, the DS75LV defaults to 9-bit resolution for software compatibility with the LM75. Communication with the DS75LV is achieved through a simple 2-wire serial interface.
PAGE 2
DS75LV Digital Thermometer and Thermostat Absolute Maximum Ratings Voltage on VDD, Relative to Ground.....................-0.3V to +4.0V Voltage on Any Other Pin, Relative to Ground ....-0.3V to +6.0V Operating Temperature Range.......................... -55°C to +125°C Storage Temperature Range............................. -55°C to +125°C Lead Temperature (soldering, 10s)..................................
PAGE 3
DS75LV Digital Thermometer and Thermostat AC Electrical Characteristics (continued) (1.7V ≤ VDD ≤ 3.7V, TA = -55°C to +125°C, unless otherwise noted.) PARAMETER Low Period of SCL SYMBOL CONDITIONS MIN TYP MAX UNITS tLOW (Note 6) 1.3 µs tHIGH (Note 6) 0.6 µs Repeated START Condition Setup Time to Rising SCL tSU:STA (Note 6) 600 ns Data-Out Hold Time from Falling SCL tHD:DAT (Notes 6, 8) Data-In Setup Time to Rising SCL tSU:DAT (Note 6) High Period of SCL 0 0.
PAGE 4
DS75LV Digital Thermometer and Thermostat Pin Description PIN NAME FUNCTION 1 SDA Data Input/Output. For 2-wire serial communication port. Open drain. 2 SCL Clock Input. 2-wire serial communication port. 3 OS Thermostat Output. Open drain. 4 GND 5 A2 Address Input 6 A1 Address Input 7 A0 Address Input 8 VDD Ground Supply Voltage. +1.7V to +3.7V supply pin.
PAGE 5
DS75LV Digital Thermometer and Thermostat Detailed Description Measuring Temperature The DS75LV measures temperature using a bandgap temperature sensing architecture. An on-board delta-sigma analog-to-digital converter (ADC) converts the measured temperature to a digital value that is calibrated in degrees centigrade; for Fahrenheit applications a lookup table or conversion routine must be used. The DS75LV is factory-calibrated and requires no external components to measure temperature.
PAGE 6
DS75LV Shutdown Mode For power-sensitive applications, the DS75LV offers a low-power shutdown mode. The SD bit in the configuration register controls shutdown mode. When SD is changed to 1, the conversion in progress is completed and the result stored in the temperature register after which the DS75LV goes into a low-power standby state. The OS output is cleared if the thermostat is operating in interrupt mode and OS remains unchanged in comparator mode.
PAGE 7
DS75LV Digital Thermometer and Thermostat Configuration Register The configuration register allows the user to program various DS75LV options such as conversion resolution, thermostat fault tolerance, thermostat polarity, thermostat operating mode, and shutdown mode. The configuration IN THIS EXAMPLE THE DS75LV IS CONFIGURED TO HAVE A FAULT TOLERANCE OF 2. register is arranged as shown in Figure 5 and detailed descriptions of each bit are provided in Table 2.
PAGE 8
DS75LV Digital Thermometer and Thermostat Table 2. Configuration Register Bit Descriptions BIT NAME FUNCTION 0 Reserved Power-up state = 0 The master can write to this bit, but it will always read out as a 0. R1 Conversion Resolution Bit 1 Power-up state = 0 Sets conversion resolution (see Table 3) R0 Conversion Resolution Bit 0 Power-up state = 0 Sets conversion resolution (see Table 3) F1 Thermostat Fault Tolerance Bit 1 Power-up state = 0 Sets the thermostat fault tolerance (see Table 4).
PAGE 9
DS75LV Register Pointer The four DS75LV registers each have a unique 2-bit pointer designation, which is defined in Table 5. When reading from or writing to the DS75LV, the user must “point” the DS75LV to the register that is to be accessed. When reading from the DS75LV, once the pointer is set, it remains pointed at the same register until it is changed.
PAGE 10
DS75LV Digital Thermometer and Thermostat … SDA … SCL START CONDITION STOP CONDITION ACK (OR NACK) FROM RECEIVER Figure 6. START, STOP, and ACK Signals BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 1 0 0 1 A2 A1 A0 R/W BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 0 0 0 0 0 0 P1 P0 Figure 7. Address Byte Figure 8. Pointer Byte General 2-Wire Information ● All data is transmitted MSb first over the 2-wire bus.
PAGE 11
DS75LV Software POR: The soft power-on reset (POR) command is 54h. The master sends a START followed by an address byte containing the DS75LV bus address. The R/W bit must be a 0. The DS75LV responds with an ACK. If the next byte is a 0x54, the DS75LV resets as if power had been cycled. No ACK is sent by the IC after the POR command is received.
PAGE 12
DS75LV Digital Thermometer and Thermostat A) READ 2 BYTES FROM THE TEMPERATURE, T OS, OR THYST REGISTER (CURRENT POINTER LOCATION) SCL SDA S 1 0 START 0 1 A2 A1 A0 R ADDRESS BYTE A D7 D6 D5 D4 D3 D2 D1 D0 A D7 D6 D5 D4 D3 D2 D1 D0 N ACK (DS75LV) MS DATA BYTE (FROM DS75LV) ACK (MASTER) LS DATA BYTE (FROM DS75LV) P NACK STOP (MASTER) B) WRITE TO THE CONFIGURATION REGISTER SCL SDA S 1 0 START 0 1 A2 A1 A0 W ADDRESS BYTE A 0 0 ACK (DS75LV) 0 0 0 0 POINTER BYTE 0 1 A D7 D6 D5
PAGE 13
DS75LV Digital Thermometer and Thermostat Ordering Information PART TEMP RANGE TOP MARK PIN-PACKAGE DS75LVS -55°C to +125°C DS75L 8 SO DS75LVS+ -55°C to +125°C DS75L* 8 SO DS75LVS/T&R -55°C to +125°C DS75L 8 SO DS75LVS+T&R -55°C to +125°C DS75L* 8 SO DS75LVU -55°C to +125°C DS75L 8 µSOP (µMAX) DS75LVU+ -55°C to +125°C DS75L** 8 µSOP (µMAX) DS75LVU/T&R -55°C to +125°C DS75L 8 µSOP (µMAX) DS75LVU+T&R -55°C to +125°C DS75L** 8 µSOP (µMAX) +Denotes a lead(Pb)-free/RoHS-comp
PAGE 14
DS75LV Digital Thermometer and Thermostat Revision History REVISION NUMBER REVISION DATE DESCRIPTION PAGES CHANGED 0 5/06 Initial release — 1 11/06 Changed the max conversion time for R1 and R0 in Table 4 8 2 12/14 Updated Benefits and Features section 1 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.