Features

Support:

-organlec A, B, C, D bands

--Rib std-t84, FCC

] --Fsk, sfsk, and nb-organ

conforming:

--en50065-1, -2, -7

–FCC, No. 1 Part 15

--Rib STD-T84

Standard:

–G3, Prime, P1901.2, ITU-G.HNEM

] Integrated power cord drive with heat protection and overcurrent protection

pins optional static current consumption:

- 40 μA in the standby mode (typical)

–51 ma, suitable for CENELEC A, B, C, D bands (typical)

–78 ma, suitable for FCC, Arib STD-T84, FCC (typical)

Packaging: 5 mm × 5 mm 20 stitches vqfn

Extended operating temperature range:

ta u003d --40 ° C to+125 ° C [ 123]

Application

EMETERING

Family Regional Network

Lighting Application [123 ]

Solar application

electric conductors and electric vehicle power supply equipment

Explanation

OPA521 is an power line communication (PLC) line line Drivers meet the conductive launch requirements in part 15 and FCC in the CENELEC A, B, C, and D bands. This device is used to drive up to 1.9A high -current and low impedance lines to enter the powerless load. With the optimized internal protection structure, OPA521 requires the smallest external protection component to achieve the minimum system solution cost.

The closed -loop gain of OPA521 is 7 and the bandwidth is 3.8MHz. Single -chip microcomputers have high reliability in power line communication applications.

OPA521 transmitting power amplifier work from 7 V to 24 V. Under the typical load current (IOUT u003d 1.9 APEAK), the wide output width makes the nominal 24 V power supplyWith 10-VPP capabilities.

Inside the device has overheating and short circuit protection. The fault detection sign indicates the current and thermal limit. Turn off the pin and place the equipment in a low power consumption, consume 40 μA (typical).

OPA521 has surface installation, 5 mm × 5 mm qfn, 20pack packaging (RGW). It is stipulated that the extended industrial connection temperature range -40 ° C to+125 ° C is operated.

Equipment information

(1), please refer to the appointment appendix at the end of the data table.

Detailed instructions

Overview

OPA521 is a power amplifier designed for power line communication (PLC) applications. This device has a fixed gain of -7V/V, a low-pass filter response, good linearity and low distortion through bandwidth. The amplifier uses 7-V to 24-V power supply, which can provide continuous currents up to ± 1.9 A within the range of -40 ° C to+125 ° C.

Figure Figure

Feature description

OPA521 provides optional output current limit (ILIM), static current (IQSet) selection lead Enable pins of the feet and equipment. Iflag output alarm quotes to indicate the output current warning. When the internal temperature inside the device is forced to close the device, the TFLAG alert trigger.

IQSET pin

The pin sets the operating frequency band of the amplifier by adjusting the static current.

IQSet GT; 2 V sets the device to work in FCC or ARIB band

IQSet LT; 0.8 V Set the device in the centerlec band

EN pin

When the transformer is not used, when the EN pin is reduced, the output is disabled and in a high impedance state. For typical operations, connect EN pins to 3.3 V. In the disable mode, the entire device consumes 40 μA (typical) current.

ILIM pin restrictions

ILIM pin (pin 12) provides a resistance to programming output current limit. Formula 1 determines the external RSET resistance value connected to the pin.

In the formula:

RSET u003d the value of the external resistor connected between the needle 26 and the ground,

] and

ILIM u003d The current limit value required.

The ILIM value given by Formula 1 has a tolerance of 30%.

IFLAG and TFLAG pin

Iflag and TFLAG pins are high levels, open drainning output, and indicate whether OPA521 is at a current or thermal limit. Connect these resistors (for example, 10Ω to 3Ω).

The maximum output current of the power amplifier is programmed to program the external ILIM resistor between ILIM (needle 12) and ground. If a failure occurs, if the amplifier enters the current limit state, the IFLAG is set. This will cause the current to be generated or absorbed by a power amplifier than the limit of programming. Iflag shows transient pulses under typical operations. The real state of iflag more than 100 milliseconds is a clear instructions for the fault current state.

The device contains internal heat shutdown protection circuits. When the knot temperature exceeds 165 ° C, the circuit can automatically turn off the output stage. Only when the knot temperature drops to less than 150 ° C, the installation heat shutdown protection circuit allows the amplifier to work normally. When the device is in the heat clearance mode.

Device function mode

OPA521 from a power rail from 7 V to 24 V. The gain setting is -7 V/V, and can be increased by connected to the outer resistor of the gain settings and the —in pin.

Application and implementation

Note: The information in the following application chapters is not part of the TI component specification, TI does not guarantee its accuracy or integrity. TI's customers are responsible for determining the applicability of the component. Customers should verify and test their design implementation to confirm the system function.

Application information

OPA521 is an integrated power line communication power amplifier, which transmits PLC data to the power line through the line coupling circuit.

Typical application

The schematic diagram of typical applications is shown in Figure 1.

Design requirements

For typical power line applications, please use the following parameters:

Example :

PRIME or G3:

p Power supply to use an OFDM signal with a 2Ω load and 1-VRMS load voltage: p power supply u003d vload × OFDM multiplier × turning ratio+(2 × vswing) (2 × vswing) (2 × vswing) (2 × vswing) (2 × vswing)

P power supply u003d 6 V × 1.5 × 1.5+(2 × 2 V)

p Power supply u003d 17.5 v

Detailed design program

System examples

Power amplifier moldBlock

The power amplifier transmits the data to the power line through the line coupling circuit. The power amplifier is composed of high conversion rate, high voltage, and large current transport amplifier. The inverter gain of the amplifier is 7V/V, which maintains good linear and low distortion within the entire bandwidth. The operating voltage of the amplifier is 7 V to 24 V. In the specified temperature range of -40 ° C to+125 ° C, the continuous output current of up to ± 1.9 A can be provided. Connecting amplifiers in typical power line communication (PLC) requires some additional components. Figure 2 shows a typical connection with the amplifier.

+Connection

+in pin provides the correct semi -power bias for the static output voltage. +In pins always connect to the DC bias of (V+)/2.

-Conneys

External capacitors (CIN) introduced single-pole Qualcomm characteristics in the transmission function. Due to the inherent low -pass transmission function of the amplifier, the combination of the CIN and the amplifier has a common response. The value of Qualcomm's deadline is determined by CIN, and CIN reacts with the input resistance of the amplifier circuit. Formula 2 Calculate this value:

In the formula: cin u003d external input capacitor and

FHP u003d The deadline for Qualcomm required.

For example, setting CIN to 3.3 NF will cause the off -cut frequency of 2.9 kHz. The rated voltage of CIN must be determined to inherit the operation of the PA power supply voltage.

CIN sets DC gains. This will cause the DC output of the amplifier to shift to the same level as+in, and the level must always be connected to the low noise -free low impedance power supply at half of the power supply voltage (V+).

Line coupling circuit

The line coupling circuit is one of the most critical circuits in the power line modem. The low -frequency signal (usually 50 Hz or 60 Hzz) of the line coupling circuit is damaged by the low -voltage regulator circuit, and the modem signal is connected to the AC power supply. Figure 3 shows a typical line coupling circuit.

Circuit protection

Power line communication is usually in a very harsh working environment for electrical components connected to the communication circuit. If there is no proper protection, noise or waves from electrical abnormalities (such as lightning, capacitor group switching, induction switches, or other power grid fault conditions) will damage high -performance integrated circuits. By using various technologies to protect equipment, power amplifiers can survive under the worst conditions.

The protection circuit is arranged, and the metal oxide voltage -sensitive resistor (MOV),Transient voltage suppress the diode (TVS), Schottky diode, and Zina diode to eliminate electrical interference as much as possible. These components eliminated electrical interference before reaching the device. Figure 4 shows the recommended transient overvoltage protection strategy.

High -voltage coupling convergence container must be able to withstand the pulse of clamp protection provided by MOV. A metallic polypropylene capacitor (such as 474MKPA275KA capacitors in Illinois #8482;) rated voltage is 50 Hz to 60 Hz, and 250 volts of AC voltage to 310 volts, which can withstand 24 2.5 kV pulse.

Table 2 and Table 3 list several recommended transient protection elements.

(1), the Qina breakdown voltage is selected under the minimum availability of the working range beyond the range of the normal power supply. For example, 1SMB5931B design is used for systems with power factor vs u003d 15V, while 1SMB5934B design is used for systems with power factor vs u003d 20V.

(2), the selection of the TVS breakdown voltage is or slightly lower than (0.5 × PA_VS). For example, SMCJ6.0CA is designed for the system of PA_VS u003d 15 V, while SMCJ8.0CA is designed for the system of PA_VS u003d 20 V.

(3), a common value of high -voltage capacitors is 470NF. Can replace other values u200bu200baccording to application requirements. When replacement, the capacitor must be selected from the same series or the same series of capacitors. The rated value should be able to withstand the high -voltage waves on the power line to ensure reliability.

(1), the Qina breakdown voltage is selected under the minimum availability of the working range beyond the range of the normal power supply. For example, 1SMB5931B design is used for systems with power factor vs u003d 15V, while 1SMB5934B design is used for systems with power factor vs u003d 20V.

(2), the selection of the TVS breakdown voltage is or slightly lower than (0.5 × PA_VS). For example, SMCJ6.0CA is designed for the system of PA_VS u003d 15 V, while SMCJ8.0CA is designed for the system of PA_VS u003d 20 V.

(3), a common value of high -voltage capacitors is 470NF. Can replace other values u200bu200baccording to application requirements. When replacement, the capacitor must be selected from the same series or the same series of capacitors. The rated value should be able to withstand the high -voltage waves on the power line to ensure reliability.

Power suggestion

Provides two power supply feet and two grounding pins to provide a path for high current related to the low impedance of the driver AC power supply. TI recommends connecting two power supply feet together. It is recommended to bypass 47-μF to 100-μFThe capacitor is connected to the 100 NF capacitor, as close to the device as much as possible. Be careful when the high -current connecting ground wire on the wiring PCB to avoid changes in the voltage drop in PCB grounding may be changed with changes in the load current.

Layout

Layout Guide

Heat Precautions

In a typical power line communication application, when transmitted to low impedance AC lines, the device consumes the device consumption 2W power. This power consumption will increase the temperature. If the thermal design of the PCB is not achieved correctly, it will lead to the heat overload, which will cause the signal transmission to be interrupted. In order to ensure appropriate equipment temperature, maximize performance, extend the service life of the equipment, and need to manage the heat flow of the equipment appropriately, as well as good PCB design and structure.

The device was assembled in a 5-mm × 5-mm, QFN-20 package. This QFN package has a large naked hot pad at the bottom, which transmits heat from the device to the bottom PCB.

Some heat transmitted from the surface of the silicon wafer to the surrounding environment through the surface of the plastic packaging material. However, this path is not the main heat path of the heat flow, because plastic is a relatively poor heat conductor. The heat flows across the surface of the silicon chip, connects to the packaging lead through the wire, and reaches the top layer of the PCB. Although these heat flow paths are important, most (nearly 80%) of heat flowing down through silicon chips, flowing to the thermal chip, attached to epoxy resin, and attached to the exposed thermal pads at the bottom of the packaging (as shown in Figure 5) Essence To maximize the heat resistance from this down path to the surrounding environment, to maximize the life and performance of the equipment.

The exposed thermal pads must be welded on the PCB hot pad. The thermal pads on the PCB must be the same as the exposed thermal pads below QFN packaging. See QFN/SONPCBTACHMENT to obtain the advice of connecting hot pads to PCB. Figure 6 shows the heat diffusion direction from device to PCB.

If the heat path is uninterrupted, then the heat spreads to the maximum of PCB. If the thermal diffusion surface is filled with copper as much as possible, the best effect can be obtained, so that the percentage of the area covered by each layer can maximize the area. For example, a hot and stable multi -layer PCB design consists of four layers, the top layer of the copper (CU) coverage rate is 60%, the inner layer is 85%and 90%, and the bottom layer is 95%.

Increasing the number of layers of PCB, thicker copper, and increasing PCB area are all factors to improve heat communication. Figure 7 to 9 shows the function of thermal resistance as a function of these factors.

layout example