ZHCSGB8C May 2017 – October 2019 TMP464
PRODUCTION DATA.
- 1 特性
- 2 應用
- 3 說明
- 4 修訂歷史記錄
- 5 Pin Configuration and Functions
- 6 Specifications
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3 Feature Description
- 7.4 Device Functional Modes
- 7.5 Programming
- 7.6
Register Maps
- 7.6.1
Register Information
- 7.6.1.1 Pointer Register
- 7.6.1.2 Local and Remote Temperature Value Registers
- 7.6.1.3 Software Reset Register
- 7.6.1.4 THERM Status Register
- 7.6.1.5 THERM2 Status Register
- 7.6.1.6 Remote Channel Open Status Register
- 7.6.1.7 Configuration Register
- 7.6.1.8 η-Factor Correction Register
- 7.6.1.9 Remote Temperature Offset Register
- 7.6.1.10 THERM Hysteresis Register
- 7.6.1.11 Local and Remote THERM and THERM2 Limit Registers
- 7.6.1.12 Block Read - Auto Increment Pointer
- 7.6.1.13 Lock Register
- 7.6.1.14 Manufacturer and Device Identification Plus Revision Registers
- 7.6.1
Register Information
- 8 Application and Implementation
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文檔支持
- 12機械、封裝和可訂購信息
10.1 Layout Guidelines
Remote temperature sensing on the TMP464 device measures very small voltages using very low currents; therefore, noise at the device inputs must be minimized. Most applications using the TMP464 device have high digital content, with several clocks and a multitude of logic-level transitions that create a noisy environment. Layout must adhere to the following guidelines:
- Place the TMP464 device as close to the remote junction sensor as possible.
- Route the D+ and D– traces next to each other and shield them from adjacent signals through the use of ground guard traces, as shown in Figure 23. If a multilayer PCB is used, bury these traces between the ground or V+ planes to shield them from extrinsic noise sources. TI recommends 5-mil (0.127 mm) PCB traces.
- Minimize additional thermocouple junctions caused by copper-to-solder connections. If these junctions are used, make the same number and approximate locations of copper-to-solder connections in both the D+ and D– connections to cancel any thermocouple effects.
- Use a 0.1-μF local bypass capacitor directly between the V+ and GND of the TMP464. For optimum measurement performance, minimize filter capacitance between D+ and D– to 1000 pF or less. This capacitance includes any cable capacitance between the remote temperature sensor and the TMP464.
- If the connection between the remote temperature sensor and the TMP464 is wired and is less than eight inches (20.32 cm) long, use a twisted-wire pair connection. For lengths greater than eight inches, use a twisted, shielded pair with the shield grounded as close to the TMP464 device as possible. Leave the remote sensor connection end of the shield wire open to avoid ground loops and 60-Hz pickup.
- Thoroughly clean and remove all flux residue in and around the pins of the TMP464 device to avoid temperature offset readings as a result of leakage paths between D+ and GND, or between D+ and V+.
NOTE: Use a minimum of 5-mil (0.127 mm) traces with 5-mil spacing.
Figure 23. Suggested PCB Layer Cross-Section