DS7505 ,High-Precision Digital Thermometer and ThermostatApplications with Multidrop Capability• Up to Eight Devices Can Operate on a 2-Wire Bus● Any Therma ..
DS7505U+ ,High-Precision Digital Thermometer and ThermostatElectrical Characteristics(1.7V ≤ V ≤ 3.7V, T = -55°C to +125°C, unless otherwise noted.)DD APARAME ..
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ECH8604 ,N CHANNEL MOS SILICON TRANSISTOR
DS7505-DS7505U+
High-Precision Digital Thermometer and Thermostat
General DescriptionThe DS7505 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
±0.5°C accuracy over a -0°C to +70°C range. A 9-bit reso-
lution mode is software compatible with the LM75.
The DS7505 thermostat has a dedicated open-drain
output (O.S.) and programmable fault tolerance, which
allows the user to define the number of consecutive error
conditions that must occur before O.S. is activated. There
are two thermostatic operating modes that control thermo-
stat operation based on user-defined trip points (TOS and
THYST) that are stored in EEPROM registers.
Applications●Networking Equipment●Cellular Base Stations●Ofice Equipment●Medical Equipment●Any Thermally Sensitive System
Beneits and Features●Extends Performance Range with a Low-Voltage,
1.7V to 3.7V Operating Range●Maximizes System Accuracy in Broad Range of
Thermal Management ApplicationsMeasures Temperature from -55°C to +125°C
(-67°F to +257°F)±0.5°C Accuracy Over a 0°C to +70°C RangeUser-Conigurable Resolution from 9 Bits (Default)
to 12 Bits (0.5°C to 0.0625°C Resolution)●Reduces Cost with No External Components and
Stand Alone Thermostat Capability●Increases Reliability and System RobustnessInternally Filtered Data Lines for Noise Immunity
(50ns Deglitch)Bus Timeout Feature Prevents Lockup on a 2-Wire
Interface●Simplifies Distributed Temperature-Sensing
Applications with Multidrop CapabilityUp to Eight Devices Can Operate on a 2-Wire Bus●Fast 25ms (max) 9-Bit Conversion Time●Flexible and Nonvolatile (NV) User-Defined
Thermostatic Modes
μMAX is a registered trademark of Maxim Integrated Products, Inc.
Commands are capitalized for clarity.
+Denotes a lead(Pb)-free/RoHS-compliant package.
T&R = Tape and reel.
PARTTEMP RANGEPIN-PACKAGEDS7505S+-55°C to +125°C8 SO (150 mils)
DS7505S+T&R-55°C to +125°C8 SO (150 mils),
2500-Piece T&R
DS7505U+-55°C to +125°C8 µMAX®
DS7505U+T&R-55°C to +125°C8 µMAX,
3000-Piece T&R
TOP VIEW7A0SCL8VDDSDAO.S.36GND45
DS7505
µMAX7A0SCL8VDDSDAO.S.36GND45
DS7505
DS7505Digital Thermometer and Thermostat
Pin Conigurations
Ordering Information
Voltage Range on VDD Relative to Ground .........-0.3V to +4.0V
Voltage Range on Any Other PinRelative to Ground............................................-0.3V to +6.0V
Operating Temperature Range .........................-55°C to +125°C
Storage Temperature Range ............................-55°C to +125°C
Soldering Temperature .........................Refer to the IPC/JEDEC
J-STD-020 Specification.
(1.7V ≤ VDD ≤ 3.7V, TA = -55°C to +125°C, unless otherwise noted.)
PARAMETERSYMBOLCONDITIONSMINMAXUNITSSupply VoltageVDD1.73.7V
Input Voltage Range (SDA, SCL,
O.S., A0, A1, A2)(Note 1)-0.3+5.5V
Thermometer Error
(Note 2, 3)TERR0°C to +70°C
±0.5°C
-55°C to +125°C
±2.0Input Logic-HighVIH(Note 1)0.7 x VDDV
Input Logic-LowVIL(Note 1)0.3 x VDDV
SDA Output Logic-Low Voltage VOL16mA sink current (Note 1)00.6V
O.S. Saturation VoltageVOL24mA sink current (Notes 1, 2)0.8V
Input Current Each I/O pin0.4V < VI/O < 0.9 x VDD-10+10µA
I/O CapacitanceCI/O10pF
Standby CurrentIDD1(Notes 4, 5, 6)2µA
Active Current
(Notes 4, 5, 6)IDD
Active temp conversions750Communication only100
E2 Copy only500
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSResolution912Bits
Temperature Conversion TimetCONVT
9-bit conversions25
10-bit conversions50
11-bit conversions100
12-bit conversions200
SCL FrequencyfSCL400kHz
EEPROM Copy TimetWR-40°C to +85°C10ms
EEPROM Copy EnduranceNEEWR-40°C ≤ TA ≤ +85°C (Note 7)10k20kCycles
TA = +25°C (Note 7)40k80k
DS7505Digital Thermometer and Thermostat
Absolute Maximum RatingsStresses 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.
AC Electrical Characteristics(1.7V ≤ VDD ≤ 3.7V, TA = -55°C to +125°C, unless otherwise noted.)
DC Electrical Characteristics
(1.7V ≤ VDD ≤ 3.7V, TA = -55°C to +125°C, unless otherwise noted.)
Note 1: All voltages are referenced to ground.
Note 2: Internal heating caused by O.S. loading causes the DS7505 to read approximately 0.5°C higher if O.S. is sinking the max-
rated current.
Note 3: Specified in 12-bit conversion mode. Quantization error must be considered when converting in lower resolutions.
Note 4: IDD specified with O.S. pin open.
Note 5: IDD specified with VDD at 3.0V and SDA, SCL = 3.0V, TA = -55°C to +85°C.
Note 6: IDD specified with A0, A1, A2 = 0V or VDD.
Note 7: VDD must be > 2.0V.
Note 8: E2 Copy occurs at +25°C.
Note 9: See the timing diagram (Figure 1). All timing is referenced to 0.9 x VDD and 0.1 x VDD.
Note 10: After this period, the first clock pulse is generated.
Note 11: The DS7505 provides an internal hold time of at least 75ns on the SDA signal to bridge the undefined region of SCL’s fall-
ing edge.
Note 12: This timeout applies only when the DS7505 is holding SDA low. Other devices can hold SDA low indefinitely and the DS7505 does not reset.
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSEEPROM Data RetentiontEEDR-40°C to +125°C (Note 8)10Years
Bus Free Time Between a STOP
and START ConditiontBUF(Note 9)1.3µs
START and Repeated START Hold
Time from Falling SCLtHD:STA(Notes 9, 10)600ns
Low Period of SCL tLOW(Note 9)1.3µs
High Period of SCL tHIGH(Note 9)0.6µs
Repeated START Condition Setup
Time to Rising SCL tSU:STA(Note 9)600ns
Data-Out Hold Time from Falling
SCLtHD:DAT(Notes 9, 11)00.9µs
Data-In Setup Time to Rising SCLtSU:DAT(Note 9)100ns
Rise Time of SDA and SCL
(Receive)tR(Notes 9, 12)1000ns
Fall Time of SDA and SCL
(Receive)tF(Notes 9, 12)300ns
Spike Suppression Filter Time
(Deglitch Filter) tSS050ns
STOP Setup Time to Rising SCL tSU:STO(Note 9)600ns
Capacitive Load for Each Bus LineCB400pF
Input CapacitanceCI5pF
Serial Interface Reset TimetTIMEOUTSDA time low (Note 12)75325ms
DS7505Digital Thermometer and Thermostat
AC Electrical Characteristics (continued)
Figure 1. Timing Diagram
PINNAMEFUNCTIONSDAData Input/Output. For 2-wire serial communication port. Open drain.SCLClock Input. For 2-wire serial communication port.O.S.Thermostat Output. Open drain.GNDGroundA2Address InputA1Address InputA0Address InputVDDSupply Voltage. +1.7V to +3.7V supply pin.
OVERSAMPLING
MODULATOR
DIGITAL
DECIMATOR
PRECISION
REFERENCE
ADDRESS
AND
I/O CONTROL
VDD
CONFIGURATION
REGISTER
TEMPERATURE
REGISTER
SCL
SDA
O.S.
GND
TOS AND THYST
REGISTERS
THERMOSTAT
COMPARATOR
DS7505SDA
SCLP
tHD:STA
tLOW
tHD:DAT
tSU:DAT
tHD:STA
tSU:STA
tSPtBUF
tSU:STO
DS7505Digital Thermometer and Thermostat
Pin Description
Operation—Measuring TemperatureThe DS7505 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 Celsius; for Fahrenheit applications a lookup
table or conversion routine must be used. The DS7505 is
factory-calibrated and requires no external components to
measure temperature.
The DS7505 can be configured to power up either auto-
matically converting temperature or in a low-power standby
state. The preferred power-up mode can be set using the
SD bit in the configuration register as explained in the Configuration Register section. The resolution of the digital
output data is user-configurable to 9, 10, 11, or 12 bits,
corresponding to temperature increments of 0.5°C, 0.25°C,
0.125°C, and 0.0625°C, respectively. The factory default
resolution at power-up is 9 bits (R1 = 0, R0 = 0), however
this can be programmed to 10, 11, or 12 bits using the R0
and R1 bits in the configuration register as explained in the Configuration Register section. Note that the conversion
time doubles for each additional bit of resolution.
After each temperature measurement and analog-to-digital
(A/D) conversion, the DS7505 stores the temperature as a
16-bit two’s complement number in the 2-byte temperature
register (see Figure 3). The sign bit (S) indicates if the tem-
perature is positive or negative: for positive numbers S =
0 and for negative numbers S = 1. The most recently con-
verted digital measurement can be read from the tempera-
ture register at any time. Since temperature conversions
are performed in the background, reading the temperature
register does not affect the operation in progress.
Bits 3 through 0 of the temperature register are hardwired
to 0. When the DS7505 is configured for 12-bit resolution,
the 12 MSBs (bits 15 through 4) of the temperature reg-
ister contain temperature data. For 11-bit resolution, the
11 MSBs (bits 15 through 5) of the temperature register
contain data, and bit 4 reads out as 0. Likewise, for 10-bit
resolution, the 10 MSBs (bits 15 through 6) contain data,
and for 9-bit the 9 MSBs (bits 15 through 7) contain data
and all unused LSBs contains 0s. Table 1 gives examples
of 12-bit resolution digital output data and the correspond-
ing temperatures.
Figure 3. Temperature, TOS, and THYST Register Format
Table 1. 12-Bit Resolution Temperature/Data Relationship
TEMPERATURE (°C)DIGITAL OUTPUT(BINARY)
DIGITAL OUTPUT(HEX)+1250111 1101 0000 00007D00
+25.06250001 1001 0001 00001910
+10.1250000 1010 0010 00000A20
+0.50000 0000 1000 000000800000 0000 0000 00000000
-0.51111 1111 1000 0000FF80
-10.1251111 0101 1110 0000F5E0
-25.06251110 0110 1111 0000E6F0
-551100 1001 0000 0000C900
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
MS Byte S 26 25 24 23 22 21 20Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
LS Byte 2-1 2-2 2-3 2-4 0 0 0 0
DS7505Digital Thermometer and Thermostat
Shutdown ModeFor power-sensitive applications, the DS7505 offers a
low-power shutdown mode. The SD bit in the configura-
tion register controls shutdown mode. When SD is pro-
grammed to 1, the conversion in progress is completed
and the result stored in the temperature register, after
which the DS7505 goes into a low-power standby state.
The O.S. output is cleared if the thermostat is operating
in interrupt mode and O.S remains unchanged in com-
parator mode. The 2-wire interface remains operational in
shutdown mode, and writing a 0 to the SD bit returns the
DS7505 to normal operation. Upon power-up in shutdown
mode, the DS7505 executes one temperature measure-
ment. The result is stored in the temperature register,
after which the DS7505 enters the shutdown state.
Operation—ThermostatThe DS7505 thermostat can be programmed to power
up in either comparator mode or interrupt mode, which
activate and deactivate the open-drain thermostat output
(O.S.) based on user-programmable trip points (TOS and
THYST). The THYST and TOS registers contain Celsius
temperature values in two’s complement format and
consist of EEPROM that is shadowed by SRAM. Once
written to the shadow SRAM, values can be stored in
EEPROM by issuance of a Copy Data command from the
master (see the Command Set section for more details).
The device can operate using the shadow SRAM only or
using the EEPROM. If the EEPROM is used, the values
are NV and can be programmed prior to installation of the
DS7505 for standalone operation. The factory power-up
settings for the DS7505 are with the thermostat in com-
parator mode, active-low O.S. polarity, overtemperature
trip-point (TOS) register set to 80°C, the hysteresis trip-
point (THYST) register set to +75°C, and the number of
consecutive conversion to trigger O.S. set to 1. If these
power-up settings are compatible with the application, the
DS7505 can be used as a stand-alone thermostat (i.e.,
no 2-wire communication required) with no programming
required prior to installation. If interrupt mode operation,
active-high O.S. polarity, different TOS and THYST values,
or a different number of conversions to trigger O.S. are
desired, they must be programmed into the EEPROM
either after initial power-up or prior to IC installation. The
programmed values then become the new power-up
defaults.
In both operating modes, the user can program the ther-
mostat-fault tolerance, which sets how many consecutive
temperature readings (1, 2, 4, or 6) must fall outside the
thermostat limits before the thermostat output is triggered.
The fault tolerance is set by the F1 and F0 bits in the con-
figuration register. The default factory power-up setting for
fault tolerance is 1 (F1 = 0, F0 = 0).
The data format of the TOS and THYST registers is identi-
cal to that of the temperature register (see Figure 3), i.e.,
a 2-byte two’s complement representation of the trip-point
temperature in degrees Celsius with bits 3 through 0
hardwired to 0. After every temperature conversion, the
measurement is compared to the values stored in the TOS
and THYST registers. The O.S. output is updated based
on the result of the comparison and the operating mode
of the IC. The number of TOS and THYST bits used dur-
ing the thermostat comparison is equal to the conversion
resolution set by the R1 and R0 bits in the configuration
register. For example, if the resolution is 9 bits, only the
9 MSBs of TOS and THYST are used by the thermostat
comparator.
The active state of the O.S. output can be programmed
by the POL bit in the configuration register. The powerup
factory default is active low (POL = 0).
If the user does not wish to use the thermostat capabili-
ties of the DS7505, the O.S. output should be left uncon-
nected. Note that if the thermostat is not used, the TOS
and THYST registers can be used for general storage of
system data.
Comparator ModeWhen the thermostat is in comparator mode, O.S. can be
programmed to operate with any amount of hysteresis.
The O.S. output becomes active when the measured tem-
perature exceeds the TOS value a consecutive number of
times as defined by the F1 and F0 fault tolerance (FT) bits
in the configuration register. O.S. then stays active until
the first time the temperature falls below the value stored
in THYST. Putting the device into shutdown mode does
not clear O.S. in comparator mode. Thermostat compara-
tor mode operation with FT = 2 is illustrated in Figure 4.
DS7505Digital Thermometer and Thermostat
Interrupt ModeIn interrupt mode, the O.S. output first becomes active
when the measured temperature exceeds the TOS value
a consecutive number of times equal to the FT value in
the configuration register. Once activated, O.S. can only
be cleared by either putting the DS7505 into shutdown
mode or by reading from any register (temperature,
configuration, TOS, or THYST) on the device. Once O.S.
has been deactivated, it is only reactivated when the
measured temperature falls below the THYST value a
consecutive number of times equal to the FT value. Again,
O.S can only be cleared by putting the device into shut-
down mode or reading any register. Thus, this interrupt/
clear process is cyclical between TOS and THYST events
(i.e, TOS, clear, THYST, clear, TOS, clear, THYST, clear,
etc.). Thermostat interrupt mode operation with FT = 2 is
illustrated in Figure 4.
Figure 4. O.S. Output Operation Example
IN THIS EXAMPLE, THE DS7505 IS CONFIGURED
TO HAVE A FAULT TOLERANCE OF 2.
TOS
THYST
TEMPERATURE
O.S. OUTPUT—COMPARATOR MODE
O.S. OUTPUT—INTERRUPT MODE
INACTIVE
INACTIVE
ACTIVE
ACTIVE
CONVERSIONS
ASSUMES A READ
HAS OCCURED
DS7505Digital Thermometer and Thermostat
