TPA3123D2PWPR DataSheet
DATASHEET
TPA3123D2PWPR Description
• Average CRT cut-off voltages • Maximum average beam currents • Highest duty cycle Once these parameters are known, the system designer can then calculate the maximum ambient temperature surround- ing the TPA3123D2PWPR without a heat sink. A small, low-cost heat sink may be used if the calculated maximum ambient tem- perature does not satisfy the worst-case operating tempera- ture inside the TV. The following example shows how to determine the maxi- mum power dissipation and maximum ambient temperature and assumes the recommended application circuit is used (see Figure 6). Example The TPA3123D2PWPR uses 1.0W of static power from the 220V and 8V supplies, assuming the worst-case supply currents. If the average CRT cut-off voltage of all channels is 180V and each TPA3123D2PWPR output sinks a maximum average beam cur- rent of 1.0 mA at 77% duty cycle (480p format) at the highest brightness setting, the TPA3123D2PWPR will dissipate: PDISS = PSTATIC + 3 x (VCUT-OFF x IAVGMAX) x ä, or PDISS = 1.0W + 3 x (180V x 1.0 mA) x 0.77 = 1.42W. The maximum thermal resistance from junction-to-air, JA, and maximum junction temperature, TJMAX, are stated in the Section Absolute Maximum Ratings . Therefore, the maxi- mum ambient temperature surrounding the TPA3123D2PWPR can be calculated: TAMAX = TJMAX - (PDISS x JA), or TAMAX = 150˚C - (1.42W x 68˚C/W) = 53˚C.
TPA3123D2PWPR Features
ADJ: In the adjustable version, the user programs the output voltage with two external resistors. The resistors should be 0.1% for high accuracy. The output amplifier is configured as a noninverting operational amplifier. The resistors should meet the criteria of R3 || R4 < 100 Ω. Connect ADJ to VOUT for an output voltage of 1.2 V. Note that the point at which the feedback network is connected to the output is the Kelvin sense point.
TPA3123D2PWPR Applicatioins
Technical/Catalog InformationTPA3123D2PWPRVendorTexas Instruments (VA)CategoryIntegrated Circuits (ICs) Package / Case