Diodes PAM8908 User Manual

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25mW TRUE CAP FREE STEREO HEADPHONE AMPLIFIER

Description

The PAM8901 / PAM8908 stereo headphone driver is designed for portable equipment where board space is at a premium. The PAM8901 / PAM8908 uses a unique, patent pending architecture to produce a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors, saving cost, board space, and component height.

The PAM8901 / PAM8908 delivers up to 25mW per channel into a 16Ω load and has low 0.03% THD+N. A high power-supply rejection ratio (80dB at 1kHz) allows this device to operate from noisy digital supplies without an additional linear regulator.

The PAM8901 / PAM8908 operates from a single supply from 2.5V t o

5.5V, has short-circuit and over temperature protection. Shutdown mode reduces supply current to less than 1µA.

Features

• Patent Pending 3 Phase Power Line Shift Charge Pump Eliminates Need for DC-Blocking Capacitors

• TrueCapFree Architecture, Output Biased at 0V (System Ground)

• Excellent Low Frequency Fidelity

• 80dB PSRR at 1kHz

• Less than 1uA Shutdown current

• Support both Fully differential and Single-Ended Inputs

• Short Circuit and Over Temperature Protection

• Selectable Gain settings:-6dB,0dB,3dB and 6dB

• Available in Space Saving Packages: TQFN3x3-16L

Typical Applications Circuit

Typical Applcation Configuration with Differential Input Signals

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Pin Assignments

Applications

• Smart Phones/Cellular Phones

• Notebook Computers

• Portable DVD Player

• Personal Digital Assistants (PDAs )

• Electronic Dictionaries

• Digital Still Cameras

• Portable Gaming

PAM8901 / PAM8908

PAM8901/

PAM8908

PAM8901 / PAM8908

Document number: DSxxxxx Rev. 1 - 1

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Typical Applications Circuit (cont.)

Typical Applcation Configuration with Single-Ended Input Signal

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PAM8901 / PAM8908

PAM8901/

PAM8908

Pin Descriptions

Pin Number

PAM8901 PAM8908

1 2 3 4 5

1 INL- 2 INL+ 3 INR+ 4 INR- 6 G0

6 7 G1 I 7

5 OUTR

8 8 HPVSS P

9 10 PGND P 10 9 CAP- O 11 11 CAP+ O 12 14 PVDD P Power V 13 12 HPVDD O Positive power supply for headphone amplifiers. Charge pump positive half V 14 16 OUTL O 15 15 SGND I 16 13 EN I

PAM8901 / PAM8908

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T-QFN3x3-16L

Pin Name

I/O/P Function

Inverting left input for differential signals.

I

Non-inverting left input for differential signals.

I

Inverting right input for differential signals.

I

Non-inverting right input for differential signals.

I

Gain select bit 0

I

Gain select bit 1 Right headphone amplifier output. Connect to right terminal of headphone jack.

O

Charge pump output and negative power supply for output amplifiers; connect 1µF capacitor to GND

Power Ground Charge pump negative flying cap. Charge pump positive flying cap.

.

DD

Left headphone ampli fier output. Connect to left terminal of headphone jack. Amplifier reference voltage. Amplifier enabled. Connect to logic low to shutdown; connect to logic high to activate

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output.

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Functional Block Diagram

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PAM8901 / PAM8908

Absolute Maximum Ratings (@T

These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability. All voltages are with respect to ground.

Parameter Rating Unit

Supply Voltage (PVDD) Input Voltage (INR+, INR-, INL+, INL-) Control Interface Voltage (G0, G1, EN) Storage Temperature -65 to +150 Maximum Junction Temperature 150

Soldering Temperature 250, 10sec

= +25°C, unless otherwise specified.)

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Recommended Operating Conditions (@T

Parameter Rating Unit

Supply Voltage Range 2.5 to 5.5 V Ambient Temperature Range -40 to +85

Junction Temperature Range -40 to +125

6.0 V

HPV

-0.3 to HPVDD +0.3

SS

-0.3 to PV

= +25°C, unless otherwise specified.)

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DD

+0.3

V V

°C

Thermal Information

Parameter Symbol Package Max Unit

Thermal Resistance (Junction to Ambient) Thermal Resisitance (Junction to Case)

θ

JA

θ

JC

PAM8901 / PAM8908

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TQFN3x3-16 35 °C/W TQFN3x3-16 14 °C/W

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PAM8901 / PAM8908

Electrical Characteristics (@T

Parameter Symbol Test Conditions Min Typ Max Units

Supply Voltage Quiescent Current

Output Power per Channel Shutdown Current

EN High Level Input Voltage VIH 1.4 V EN Low Level Voltage VIL 0.6 V G0, G1 High Level Input Voltage VGH 1.4 V G0, G1Low Level Voltage VGL 0.6 V Output Offset Voltage

Closed-Loop Voltage Gain AV

Power Supply Rejection Ratio PSRR Input A C-GND, f + 1KHz, VPP = 200mV 75 dB Total Harmonic Distortion Plus Noise THD+N PO = 20mW, f = 1kHz 0.03 % Signal to Noise Ratio SNR PO = 20mW, into 16Ω 100 dB Noise Output Voltage EN A-Weighted 10 Crosstalk CS PO = 15mW, f = 1kHz 80 dB Chargepump Switching Frequency

Start-Up Time Thermal Shutdown OTP Threshold 150 °C Thermal Shutdown Hystersis OTPH Hysteresis 20 °C

PAM8901 / PAM8908

Document number: DSxxxxx Rev. 1 - 1

= +25°C, PVDD = 3.6V, RL = 16Ω unless otherwise specified.)

A

PV

V

f

I

Q

P I

SD

OS

OSC

t

ON

DD

EN = PVDD, No Load THD = 1%, f = 1kHz, R

O

THD = 1%, f = 1kHz, RL = 32Ω 25 mW EN = 0V, PVDD = 2.5V to 5.5V 0.1 1 µA

1 5 mV

G0 =0V, G1 = 0V -6 dB G0 =PVDD, G1 = 0V 0 dB G0 =0V, G1 = PVDD 3 dB G0 =PVDD, G1 = PVDD 6 dB

1.2 1.5 1.8 MHz EN from low to high 0.4 Ms

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= 16Ω 35

L

2.5 5.5 V 4 mA

µV

RMS

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