Datasheet PAM8406 (Diodes) - 9
| Fabricante | Diodes |
| Descripción | 5W Stereo Audio Amplifier with Class D/AB Switch |
| Páginas / Página | 13 / 9 — PAM8406. Application Information. Application Note. Test Setup for … |
| Formato / tamaño de archivo | PDF / 1.6 Mb |
| Idioma del documento | Inglés |
PAM8406. Application Information. Application Note. Test Setup for Performance Testing. Maximum Gain. Mode Selection
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PAM8406 Application Information Application Note
1. When the PAM8406 works in Class-D with LC filters, it should be connected with the speaker before it is powered on, otherwise it wil be damaged easily. 2. When the PAM8406 works without LC filters, it's better to add a ferrite chip bead at the outgoing line of speaker for suppressing the possible electromagnetic interference. 3. The recommended operating voltage is 5.5V. When the PAM8406 is powered with four battery cells, it should be noted that the voltage of four new dry or alkaline batteries is over 6.0V, which is higher than its operation voltage and will likely damage the device. Therefore, it is recommended to use either four Ni-MH (Nickel Metal Hydride) rechargeable batteries, or 3 dry or alkaline batteries. 4. One should not make the input signal too large. A large signal can cause the clipping of output signal when increasing the volume. This will damage the device from the PAM8406’s big gain.
Test Setup for Performance Testing
Notes: A. The AP AUX-0025 low pass filter is necessary for Class-D amplifier measurement with AP analyzer. B. Two 22μH inductors are used in series with load resistor to emulate the small speaker for efficiency measurement.
Maximum Gain
As shown in block diagram (Page 2), the PAM8406 has two internal amplifier stages. The first stage's gain is externally configurable, while the second stage's is internally fixed. The closed-loop gain of the first stage is set by selecting the ratio of RF to RI while the second stage's gain is fixed at 2x.The output of amplifier 1 serves as the input to amplifier 2, thus the two amplifiers produce signals identical in magnitude, but different in phase by 180°. Consequently, the differential gain for the IC is AVD = 20*log [2*(RF/RI)] The PAM8406 sets maximum RF =142kΩ, minimum RI =18kΩ; so the maximum closed-gain is 24dB.
Mode Selection
When mode pin high, it features Class-D; mode pin low, it’s class AB. Mode pin can’t be floating.
Mute Operation
The MUTE pin is an input for controlling the output state of the PAM8406. A logic low on this pin disables the outputs, and a logic high on this pin enables the outputs. This pin may be used as a quick disable or enable of the outputs without a volume fade. Quiescent current is listed in the electrical characteristic table. The MUTE pin can be left floating due to the internal pull-up.
Shutdown Operation
In order to reduce power consumption while not in use, the PAM8406 contains shutdown circuitry to turn off the amplifier's bias circuitry. This shutdown feature turns the amplifier off when logic low is applied to the SHDN pin. By switching the SHDN pin connected to GND, the PAM8406 supply current draw wil be minimized in idle mode. The SHDN pin can be left floating due to the internal pull-up. PAM8406 9 of 13 May 2021 Document number: DS43342 Rev. 2 - 2
www.diodes.com
© Diodes Incorporated Document Outline Pin Assignments Description Applications Features
1. When the PAM8406 works in Class-D with LC filters, it should be connected with the speaker before it is powered on, otherwise it wil be damaged easily. 2. When the PAM8406 works without LC filters, it's better to add a ferrite chip bead at the outgoing line of speaker for suppressing the possible electromagnetic interference. 3. The recommended operating voltage is 5.5V. When the PAM8406 is powered with four battery cells, it should be noted that the voltage of four new dry or alkaline batteries is over 6.0V, which is higher than its operation voltage and will likely damage the device. Therefore, it is recommended to use either four Ni-MH (Nickel Metal Hydride) rechargeable batteries, or 3 dry or alkaline batteries. 4. One should not make the input signal too large. A large signal can cause the clipping of output signal when increasing the volume. This will damage the device from the PAM8406’s big gain.
Test Setup for Performance Testing
Notes: A. The AP AUX-0025 low pass filter is necessary for Class-D amplifier measurement with AP analyzer. B. Two 22μH inductors are used in series with load resistor to emulate the small speaker for efficiency measurement.
Maximum Gain
As shown in block diagram (Page 2), the PAM8406 has two internal amplifier stages. The first stage's gain is externally configurable, while the second stage's is internally fixed. The closed-loop gain of the first stage is set by selecting the ratio of RF to RI while the second stage's gain is fixed at 2x.The output of amplifier 1 serves as the input to amplifier 2, thus the two amplifiers produce signals identical in magnitude, but different in phase by 180°. Consequently, the differential gain for the IC is AVD = 20*log [2*(RF/RI)] The PAM8406 sets maximum RF =142kΩ, minimum RI =18kΩ; so the maximum closed-gain is 24dB.
Mode Selection
When mode pin high, it features Class-D; mode pin low, it’s class AB. Mode pin can’t be floating.
Mute Operation
The MUTE pin is an input for controlling the output state of the PAM8406. A logic low on this pin disables the outputs, and a logic high on this pin enables the outputs. This pin may be used as a quick disable or enable of the outputs without a volume fade. Quiescent current is listed in the electrical characteristic table. The MUTE pin can be left floating due to the internal pull-up.
Shutdown Operation
In order to reduce power consumption while not in use, the PAM8406 contains shutdown circuitry to turn off the amplifier's bias circuitry. This shutdown feature turns the amplifier off when logic low is applied to the SHDN pin. By switching the SHDN pin connected to GND, the PAM8406 supply current draw wil be minimized in idle mode. The SHDN pin can be left floating due to the internal pull-up. PAM8406 9 of 13 May 2021 Document number: DS43342 Rev. 2 - 2
www.diodes.com
© Diodes Incorporated Document Outline Pin Assignments Description Applications Features