Datenblatt-Suchmaschine für elektronische Bauteile |
|
LM25056A Datenblatt(PDF) 11 Page - Texas Instruments |
|
|
LM25056A Datenblatt(HTML) 11 Page - Texas Instruments |
11 / 39 page SDA SCL SMBA VREF DIODE ADR0 ADR1 ADR2 VDD DGND AGND VAUX ENABLE VIN VS+ VS- SMBus Interface MMBT3904 POL REGULATOR LM25056 RS +12V CVDD VIN VOUT CVREF VDD CIN NC NC LM25056A www.ti.com SNVS785A – JANUARY 2011 – REVISED APRIL 2013 Additionally, VDD can be driven from an external source to maintain telemetry readings for VIN and temperature if the VIN drops below its operation point. To do this, use an external 5V supply driving the VDD through a Schottky diode. This allows for telemetry readings down to VIN=0. A large capacitor (100uF) can also be placed at on the VDD line to momentarily supply current to the device to similarly maintain telemetry readings that would normally shutdown and reset the device. Note that when using an external VDD drive, ENABLE will not operate independently. To use this functionality, simply connect the external VDD source to ENABLE and lower this source to put the LM25056A into low power mode. Remote Temperature Sensing The LM25056A is designed to measure temperature remotely using an MMBT3904 NPN transistor. The base and collector of the MMBT3904 should be connected to the DIODE pin and the emitter of the MMBT3904 connected to AGND. Place the MMBT3904 near the device whose temperature is to be monitored. In noisy environments with large currents or switching noise, it is especially important to bring this connection back to AGND and not just to the nearest ground plane. If the temperature of a pass MOSFET is to be measured, the MMBT3904 should be placed as close to device as the layout allows. The temperature is measured by means of a change in an external diode voltage in response to a step in current supplied by DIODE. DIODE sources 9.2 µA but pulses 240 µA once every millisecond in order to measure the diode temperature. Care must be taken in the PCB layout to keep the parasitic resistance between DIODE and the MMBT3904 low so as not to degrade the measurement. Additionally, a small 100 pF bypass capacitor can be placed in parallel with the MMBT3904 to reduce the effects of noise. The temperature can be read using the READ_TEMPERATURE_1 PMBus command (8Dh). The default warning limit of the LM25056A will cause SMBA to be pulled low if the measured temperature code exceeds 07D0h. The PMBus will also indicate an over temperature fault if the measured temperature code exceeds 0960h. These thresholds can be reprogrammed via the PMBus interface using the OT_WARN_LIMIT (51h) and OT_FAULT_LIMIT (4Fh) commands. If the temperature measurement and protection capability of the LM25056A is not used the DIODE pin should be grounded. Application Section Figure 16. Typical Application Circuit DESIGN-IN PROCEDURE (Refer to Figure 16 for Typical Application Circuit) Shown here is the step-by-step procedure for hardware design of the LM25056A. This procedure refers to section numbers that provide detailed information on the following design steps. The recommended design-in procedure is as follows: Copyright © 2011–2013, Texas Instruments Incorporated Submit Documentation Feedback 11 Product Folder Links: LM25056A |
Ähnliche Teilenummer - LM25056A |
|
Ähnliche Beschreibung - LM25056A |
|
|
Link URL |
Privatsphäre und Datenschutz |
ALLDATASHEETDE.COM |
War ALLDATASHEET hilfreich? [ DONATE ] |
Über Alldatasheet | Werbung | Kontakt | Privatsphäre und Datenschutz | Linktausch | Hersteller All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |