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| 型号： | DS1857B-050 |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 10/22页 |
| 文件大小： | 0K |
| 描述： | IC RES TEMP 50/50K W/2MON 16-BGA |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 810 |
| 接片： | 256 |
| 电阻（欧姆）： | 50k |
| 电路数： | 2 |
| 温度系数： | 标准值 50 ppm/°C |
| 存储器类型： | 非易失 |
| 接口： | I²C（设备位址） |
| 电源电压： | 3 V ~ 5.5 V |
| 工作温度： | -40°C ~ 95°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-LBGA，CSPBGA |
| 供应商设备封装： | 16-CSBGA（4x4） |
| 包装： | 托盘 |
DS1857
Dual Temperature-Controlled Resistors with
External Temperature Input and Monitors
18
____________________________________________________________________
Temperature Conversion
Temperature is sensed from an external sensor. The sen-
sor’s scale is +10mV/°C for gain and +500mV for offset at
0°C. The DS1857 accommodates a temperature range of
-40°C to 102°C for its look-up tables. The resistor look-up
tables are stepped through according to this temperature
every 2°C. The relationship between the voltage and tem-
perature is shown in Equation 2.
The direct-to-digital temperature sensor measures tem-
perature through the use of an on-chip temperature
measurement technique with an operating range from
-40°C to +102°C. Temperature conversions are initiated
upon power-up, and the most recent conversion is
stored in memory locations 60h and 61h of the Main
Device, which are updated every tframe. Temperature
conversions do not occur during an active read or write
to memory.
The value of each resistor is determined by the tempera-
ture-addressed look-up table. The look-up table assigns
a unique value to each resistor for every 2°C increment
with a 1°C hysteresis at a temperature transition over the
operating temperature range (see Figure 4).
Power-Up and Low Voltage Operation
During power-up, the device is inactive until VCC
exceeds the digital power-on-reset voltage (POD). At
this voltage, the digital circuitry, which includes the 2-
wire interface, becomes functional. However, EEPROM
backed registers/settings cannot be internally read
(recalled into shadow SRAM) until VCC exceeds the
analog power-on-reset voltage (POA) at which time the
remainder of the device becomes fully functional. Once
VCC exceeds POA, the RDYB bit in byte 6Eh of the
Main Device memory is timed to go from a 1 to a 0 and
indicates when analog to digital conversions begin. If
VCC ever dips below POA, the RDYB bit will read as a
1 again. Once a device exceeds POA and the EEP-
ROM is recalled, the values remain active (recalled)
until VCC falls below POD.
For 2-wire device addresses sourced from EEPROM
(ADFIX = 1), the device address defaults to the
address determined by the address pins until VCC
exceeds POA and the EEPROM values are recalled.
The Auxiliary Device (A0h) is always available within
this voltage window (between POD and the EEPROM
recall) regardless of the programmed state of ADEN.
Furthermore, as the device powers-up, the VCClo alarm
flag (bit 4 of 70h in Main Device) will default to a 1 until
the first VCC analog-to-digital conversion occurs and
sets or clears the flag accordingly.
2-Wire Operation
Clock and Data Transitions: The SDA pin is normally
pulled high with an external resistor or device. Data on
the SDA pin may only change during SCL-low time
periods. Data changes during SCL-high periods will
indicate a start or stop condition depending on the con-
ditions discussed below. See the timing diagrams in
Figures 5 and 6 for further details.
Start Condition: A high-to-low transition of SDA with
SCL high is a start condition, which must precede any
other command. See the timing diagrams in Figures 5
and 6 for further details.
Stop Condition: A low-to-high transition of SDA with
SCL high is a stop condition. After a read or write
sequence, the stop command places the DS1857 into a
low-power mode. See the timing diagrams in Figures 5
and 6 for further details.
Acknowledge: All address and data bytes are trans-
mitted through a serial protocol. The DS1857 pulls the
SDA line low during the ninth clock pulse to acknowl-
edge that it has received each word.
Standby Mode: The DS1857 features a low-power
mode that is automatically enabled after power-on,
after a stop command, and after the completion of all
internal operations.
Device Addressing: The DS1857 must receive an 8-bit
device address word following a start condition to enable
a specific device for a read or write operation. The
address word is clocked into this part’s MSB to LSB. The
address byte consists of Ah (1010) followed by the value
of the address pins (A1, A2, and A0) then the R/W bit. This
T
VV
mV
=
05
10
.
(1)
M6
M5
M4
M3
M2
M1
24
6
8
10
12
TEMPERATURE (°C)
MEMORY
LOCATION
INCREASING
TEMPERATURE
DECREASING
TEMPERATURE
Figure 4. Look-Up Table Temperature Hysteresis
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1857B-050+ | 功能描述:数字电位计 IC Dual Temp-Controlled Resistors RoHS:否 制造商:Maxim Integrated 电阻:200 Ohms 温度系数:35 PPM / C 容差:25 % POT 数量:Dual 每 POT 分接头:256 弧刷存储器:Volatile 缓冲刷: 数字接口:Serial (3-Wire, SPI) 描述/功能:Dual Volatile Low Voltage Linear Taper Digital Potentiometer 工作电源电压:1.7 V to 5.5 V 电源电流:27 uA 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:TQFN-16 封装:Reel |
| DS1857E-050 | 功能描述:数字电位计 IC RoHS:否 制造商:Maxim Integrated 电阻:200 Ohms 温度系数:35 PPM / C 容差:25 % POT 数量:Dual 每 POT 分接头:256 弧刷存储器:Volatile 缓冲刷: 数字接口:Serial (3-Wire, SPI) 描述/功能:Dual Volatile Low Voltage Linear Taper Digital Potentiometer 工作电源电压:1.7 V to 5.5 V 电源电流:27 uA 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:TQFN-16 封装:Reel |
| DS1857E-050/R | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Dual Temperature-Controlled Resistors with External Temperature Input and Monitors |
| DS1857E-050/T | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Dual Temperature-Controlled Resistors with External Temperature Input and Monitors |
| DS1857E-050+ | 功能描述:数字电位计 IC Dual Temp-Controlled Resistors RoHS:否 制造商:Maxim Integrated 电阻:200 Ohms 温度系数:35 PPM / C 容差:25 % POT 数量:Dual 每 POT 分接头:256 弧刷存储器:Volatile 缓冲刷: 数字接口:Serial (3-Wire, SPI) 描述/功能:Dual Volatile Low Voltage Linear Taper Digital Potentiometer 工作电源电压:1.7 V to 5.5 V 电源电流:27 uA 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:TQFN-16 封装:Reel |
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