Self-Calibrating TPOS Gear Tooth Sensor ICs
Optimized for Automotive Cam Sensing Applications
ATS673 and
ATS674
17
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
The device must be operated below the maximum junction
temperature of the device, T
J(max)
. Under certain combinations of
peak conditions, reliable operation may require derating sup-
plied power or improving the heat dissipation properties of the
application. This section presents a procedure for correlating
factors affecting operating T
J
. (Thermal data is also available on
the Allegro MicroSystems Web site.)
The Package Thermal Resistance, R
qJA
, is a figure of merit sum-
marizing the ability of the application and the device to dissipate
heat from the junction (die), through all paths to the ambient air.
Its primary component is the Effective Thermal Conductivity,
K, of the printed circuit board, including adjacent devices and
traces. Radiation from the die through the device case, R
qJC
, is
relatively small component of R
qJA
. Ambient air temperature,
T
A
, and air motion are significant external factors, damped by
overmolding.
The effect of varying power levels (Power Dissipation, P
D
), can
be estimated. The following formulas represent the fundamental
relationships used to estimate T
J
, at P
D
.
  P
D
= V
IN
 
?/DIV>
 I
IN
 
(1)
    DT = P
D
 
?/DIV>
 R
qJA
  (2)
    T
J
 = T
A
 + 擳     (3)
For example, given common conditions such as: T
A
= 25癈,
V
IN
= 12 V, I
IN
= 4 mA, and R
qJA
 = 140 癈/W, then:
    P
D
= V
IN
 
?/DIV>
 I
IN
= 12 V
?/DIV>
 4 mA = 48 mW
   DT = P
D
 
?/DIV>
 R
qJA
 = 48 mW
?/DIV>
 140 癈/W = 7癈
    T
J
 = T
A
 + DT = 25癈 + 7癈 = 32癈
A worst-case estimate, P
D(max)
, represents the maximum allow-
able power level, without exceeding T
J(max)
, at a selected R
qJA
 
and T
A
.
Example: Reliability for V
CC
 at T
A
=
 
150癈, package SE, using
minimum-K PCB.
Observe the worst-case ratings for the device, specifically:
R
qJA
=
 
101 癈/W, T
J(max)
=
 
165癈, V
CC(max)
=
 
26.5
 
V, and
I
CC(max)
=
 
11
 
mA. Note that I
CC(max)
 at T
A
=
 
150癈 is lower than
the I
CC(max)
 at T
A
=
 
25癈 given in the Operating Characteristics
table.
Calculate the maximum allowable power level, P
D(max)
. First,
invert equation 3:
  DT
max
 = T
J(max)
  T
A
 = 165
 
 

 
150
 
癈 = 15
 
This provides the allowable increase to T
J
 resulting from internal
power dissipation. Then, invert equation 2:
  P
D(max)
= DT
max
 ?R
qJA
= 15癈 ?101 癈/W = 91 mW
Finally, invert equation 1 with respect to voltage:
  V
CC(est)
 = P
D(max)
? I
CC(max)
 = 91 mW ?11 mA = 8.3 V
The result indicates that, at T
A
, the application and device can
dissipate adequate amounts of heat at voltages dV
CC(est)
.
Compare V
CC(est)
 to V
CC(max)
. If V
CC(est)
 d V
CC(max)
, then reli-
able operation between V
CC(est)
 and V
CC(max)
 requires enhanced
R
qJA
. If V
CC(est)
 e V
CC(max)
, then operation between V
CC(est)
 and
V
CC(max)
 is reliable under these conditions.
相关PDF资料
ATS682LSHTN-T IC HALL EFFECT SENSOR 4SIP
ATS685LSHTN-T IC HALL EFFECT GEAR SENSOR 4SIP
BU52001GUL-E2 IC HALL EFFECT SW BIPO VCSP50L1
BU52003GUL-E2 IC HALL EFFECT SW BIPO VCSP50L1
BU52014HFV-TR IC HALL EFFECT SW BIPO HVSOF5
BU52040HFV-TR IC HALL EFFECT BIPO LATCH HVSOF5
D6B-2P SENSR TILT 35-65DEG 1MA SMD GUL
D7E-3 SENSOR TILT 50-80DEG 0.1A GRY
相关代理商/技术参数
ATS675LSE 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications
ATS675LSETN-HT-T 制造商:Allegro MicroSystems LLC 功能描述:
ATS675LSETN-LT-T 功能描述:IC SENSOR GEAR TOOTH 4-SIP RoHS:是 类别:传感器,转换器 >> 磁性 - 霍尔效应,数字式开关,线性,罗盘 (IC) 系列:- 标准包装:1 系列:- 传感范围:20mT ~ 80mT 类型:旋转 电源电压:4.5 V ~ 5.5 V 电流 - 电源:15mA 电流 - 输出(最大):- 输出类型:数字式,PWM,8.5 位串行 特点:可编程 工作温度:-40°C ~ 150°C 封装/外壳:20-SSOP(0.209",5.30mm 宽) 供应商设备封装:20-SSOP 包装:Digi-Reel® 其它名称:AS5132-HSST-500DKR
ATS679532-1 制造商:APPLICATION TOOLING 功能描述:
ATS682LSH 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Miniature, Two-Wire, True Zero Speed Differential Peak-Detecting Sensor IC
ATS682LSHTN-T 功能描述:IC HALL EFFECT SENSOR 4SIP RoHS:是 类别:传感器,转换器 >> 磁性 - 霍尔效应,数字式开关,线性,罗盘 (IC) 系列:- 标准包装:1 系列:- 传感范围:20mT ~ 80mT 类型:旋转 电源电压:4.5 V ~ 5.5 V 电流 - 电源:15mA 电流 - 输出(最大):- 输出类型:数字式,PWM,8.5 位串行 特点:可编程 工作温度:-40°C ~ 150°C 封装/外壳:20-SSOP(0.209",5.30mm 宽) 供应商设备封装:20-SSOP 包装:Digi-Reel® 其它名称:AS5132-HSST-500DKR
ATS684LSNTN-T 功能描述:TWO-WIRE DIFF SPEED SENSOR IC WI 制造商:allegro microsystems, llc 系列:- 包装:剪切带(CT) 零件状态:在售 功能:专用型 技术:霍尔效应 极化:单向 感应范围:70% 跳闸,30% 释放 测试条件:25°C 电压 - 电源:4 V ~ 24 V 电流 - 电源(最大值):16mA 电流 - 输出(最大值):- 输出类型:电流源 特性:- 工作温度:-40°C ~ 150°C 封装/外壳:3-SIP 供应商器件封装:3-SIP 标准包装:1
ATS685LSH 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Two-Wire, Zero Speed Differential Gear Tooth Sensor IC