PAM8907 EVB User Guide

General Description

This evaluation board user guide offers a simple and quick overview of the PAM8907. The PAM8907 is a piezoelectric horn driver with a built-in boost converter. The boost converter operates at a fixed frequency of 1.8MHz and provides a selectable 11V or 15.6V output with a minimum number of external components.

Key Features

• Input Supply Voltage Range: 1.8V to 5.5V
• Integrated Synchronous Boost Converter can be set (using VSET pin) to generate: VOUT = 11.0V to drive piezo sounder with 22Vpp or VOUT = 15.6V to drive piezo sounder with 31Vpp
• Very short turn-on/turn-off times
• Low current consumption
• Automatic wake-up and shutdown control

Evaluation Board Schematic

[Diagram Description: Figure 1 depicts the circuit schematic for the PAM8907 evaluation board. It shows the PAM8907 integrated circuit (U1) as the central component, connected to external components including inductor L1, capacitors C1, C2, C3, C4, and C5, and diode D1. Input power (VIN) is provided via connector J1. The VSET pin is used to select the boost converter output voltage (11V or 15.6V). The DIN pin controls the device operation, and the output signals OUTP and OUTN are connected to the PIE1 connector for driving a piezo sounder.]

Evaluation Board View

[Diagram Description: Figure 2 presents a visual overview of the PAM8907 evaluation board. Key connectors are clearly labeled: J1 for VIN (Input Power Supply), J3 also for VIN, J2 for the DIN Input signal, and PIE1 for the PIEZO Output. The board also indicates the Boost VOUT selection points, labeled 'H' for VOUT = 15.6V and 'L' for VOUT = 11.0V.]

EVB Operational Sequence

1. Preset the power supply to be between 1.8V and 5.5V.
2. Turn off the power supply.
3. Connect the power supply to the EVB's input supply connector.
4. Connect DIN input to the demo board input jack.
5. Connect the PIEZO to the output jack.
6. Turn on the power supply.
7. Turn on DIN.

External Components Selection

Power Supply Decoupling Caps (C1, C2)

• Low ESR for good THD, PSRR.
• C1 must be placed very close to the inductor.
• C3 must be placed very close to the IC Pin 10.

Bootstrap Capacitor (C4)

• For lower output ripple, low ESR is required.
• For low leakage current, 0.1uF, a X5R/X7R ceramic capacitor is recommended.

VCC Capacitor (C3)

• 1uF, X5R/X7R ceramic capacitor is recommended
• Place very close to the device.

PCB Layout Guidelines

Grounding

• Use plane grounding or separate grounds.
• Do not use the same trace to connect the power GND and analog GND.
• Place multiple vias to connect the top plane GND to the bottom plane.
• Connect the PAM8907's exposed pad to the backplane GND using vias.

Power Supply

• Run separate traces for Boost Input Supply and VIN from the input power supply terminal.
• It is recommended to route all power supply traces to be as short and thick as possible.
• Any barricades placed in the power supply trace may result in poor amplifier performance.

Components Placement

• Power supply capacitor, C1, should be placed very close to L1 pins.
• Power supply capacitor, C5, should be placed very close to PAM8907 VOUT pins.

PCB Layout Example

[Diagram Description: Figure 3 shows the top layer of the printed circuit board (PCB) layout for the PAM8907 evaluation board. It illustrates the placement of components such as the PAM8907 IC (U1), inductor L1, capacitors C1-C5, and diode D1. Connectors J1, J3, J2, J4, and PIE1 are also shown, along with ground planes and power traces, demonstrating optimal routing for performance.]

[Diagram Description: Figure 4 illustrates the bottom layer of the PCB layout for the PAM8907 evaluation board. This view complements the top layer by showing ground planes and routing, providing a complete picture of the board's physical design.]

Bill of Materials

Important Notice

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