参数资料
型号: MAX1298CEAE+T
厂商: Maxim Integrated
文件页数: 16/20页
文件大小: 299K
描述: IC TEMP SENS W/ADC 16-SSOP
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 2,000
功能: 温度监控系统(传感器)
传感器类型: 内部和外部
感应温度: -40°C ~ 85°C,外部传感器
精确度: ±4°C(最小值)
拓扑: ADC,多路复用器,寄存器库
输出类型: MICROWIRE?,QSPI?,SPI?
输出警报:
输出风扇:
电源电压: 4.75 V ~ 5.25 V
工作温度: -40°C ~ 85°C
安装类型: 表面贴装
封装/外壳: 16-SSOP(0.209",5.30mm 宽)
供应商设备封装: 16-SSOP
包装: 带卷 (TR)
12-Bit Serial-Output Temperature Sensors
with 5-Channel ADC
16   ______________________________________________________________________________________
Place the MAX1298/MAX1299 in a low-current power-
down state between conversions to conserve power.
Select standby, standby-plus, or shutdown through bits
PM1 and PM0 of the initialization byte (Table 4).
The MAX1298/MAX1299 assume the shutdown power
mode when V
DD
is first applied.
Standby Mode
Standby mode turns off the MAX1298/MAX1299 ADC,
internal clock, and reference buffer amplifier. Special
circuitry for temperature conversions is also deactivat-
ed. Wake-up time is limited by the reference buffer
amplifier and the associated bypass capacitor (see
Internal Reference). When an external reference is
used, wake-up time is 0.1ms.
Standby-Plus Mode
Standby-plus mode is similar to the standby mode, but
the internal reference output buffer remains active to
shorten the wake-up time to 0.1ms for internal refer-
ence mode. When using an external reference, stand-
by-plus mode is equivalent to standby mode.
Shutdown Mode
Shutdown mode turns off all functions other than start-
up circuitry, thereby reducing typical supply current to
2礎. Data registers are cleared. Use this power mode
when interconversion times are no less than 5ms.
Monitoring V
DD
This mode of operation samples and converts the sup-
ply voltage, V
DD
/4, which is internally generated. The
reference voltage must be larger than V
DD
/8 for the
operation to work properly. From the result of a conver-
sion (CODE), CODE = 256 V
DD
/ V
REF
.
Temperature Measurements
The MAX1298/MAX1299 perform temperature measure-
ments with internal or external diode-connected transis-
tors through a three-step process. First, the diode bias
current changes from 31.6礎 to 10礎 to produce a
temperature-dependent bias voltage difference, which
is amplified by a factor of 20 and converted to digital
format. Second, the bias current changes from 31.6礎
to 100礎, and the bias voltage difference is similarly
amplified by a factor of 20 and converted to digital for-
mat. Third, the intermediate results are subtracted to
achieve a digital output that is proportional to absolute
temperature in degrees Kelvin.
The reference voltage used in conjunction with tempera-
ture measurements is derived from the internal reference
source to ensure that 1LSB corresponds to 1/8 of a
degree. To convert to degrees Celsius, subtract 273.15
from the temperature inferred from the ADC output.
Temperature measurements require a conversion time
of 2.2ms.
Shield Output Buffer
The MAX1298/MAX1299 provide a shield output buffer
voltage at SHO that is approximately 0.6V (one diode
drop) above V
DD
/2. When performing temperature
measurements with an external diode, use this voltage
to suppress error-producing leakage currents (see
Remote Diode Shielding). Figure 7 shows the SHO out-
put circuit.
Applications Information
Remote Diode Selection
Temperature accuracy depends on having a good-
quality, diode-connected small-signal transistor.
Accuracy has been experimentally verified for 2N3904
devices. CPUs and other ICs having on-board temper-
ature-sensing diodes can also be monitored if the
diode connections are uncommitted.
The transistor must be a small-signal type with a base
resistance less than 100&. Tight specifications for for-
ward current gain (+50 to +150, for example) indicate
that the manufacturer has good process controls and
that the devices have consistent V
be
characteristics.
(See Table 6 for recommended devices.)
For heatsink mounting, the 500-32BT02-000 thermal
sensor from Fenwal Electronics is a good choice. This
device consists of a diode-connected transistor, an alu-
minum plate with screw hole, and twisted-pair cable
(Fenwal Inc., Milford MA, 508-478-6000).
Table 4. Power-Mode Selection
PM1
PM0
MODE
0
0
Shutdown
0
1
Standby-plus
1
0
Standby
1
1
Normal operation
5
SHO
V
DD
2
Figure 7. SHO Output Circuit
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MAX1299AEAE+ 功能描述:板上安装温度传感器 RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor
MAX1299AEAE+T 功能描述:板上安装温度传感器 12-Bit Serial-Output Temperature Sensors with 5-Channel ADC RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor
MAX1299AEAE-T 功能描述:板上安装温度传感器 RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor
MAX1299BEAE 功能描述:板上安装温度传感器 RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor