Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsLinear IC - Audio amplifier 1-channel (mono) Class G WLP 20 (2.52x2.08)

General Description

The MAX9788 features a mono Class G power amplifier

with an integrated inverting charge-pump power supply

specifically designed to drive the high capacitance of a

ceramic loudspeaker. The charge pump can supply

greater than 700mA of peak output current at 5.5VDC,

guaranteeing an output of 14V

P-P

The MAX9788 maximizes battery life by offering high-

performance efficiency. Maxim’s proprietary Class G

output stage provides efficiency levels greater than

Class AB devices without the EMI penalties commonly

associated with Class D amplifiers.

The MAX9788 is ideally suited to deliver the high out-

put-voltage swing required to drive ceramic/piezoelec-

tric speakers.

The device utilizes fully differential inputs and outputs,

comprehensive click-and-pop suppression, shutdown

control, and soft-start circuitry. The MAX9788 is fully spec-

ified over the -40°C to +85°C extended temperature range

and is available in small lead-free 28-pin TQFN (4mm x

4mm) or 20-bump WLP (2mm x 2.5mm) packages.

Features

♦ Integrated Charge-Pump Power Supply—No

Inductor Required

♦ 14V

P-P

Voltage Swing into Piezoelectric Speaker

♦ 2.7V to 5.5V Single-Supply Operation

♦ Clickless/Popless Operation

♦ Small Thermally Efficient Packages

4mm x 4mm 28-Pin TQFN

2mm x 2.5mm 20-Bump WLP

MAX9788

14V

P-P

, Class G Ceramic Speaker Driver

________________________________________________________________

Maxim Integrated Products

Ordering Information

MAX9788

IN+

FB+

IN+

CPV

2.7V TO 5.5V

IN-

FB-

OUT+

OUT-

CLASS G

OUTPUT

STAGE

CHARGE

PUMP

FB+

FB-

CPGNDGND

Simplified Block Diagram

19-0710; Rev 3; 5/08

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

Typical Application Circuit/Functional Diagram and Pin

Configurations appear at end of data sheet.

EVALUATION KIT

AVAILABLE

Cell Phones

Smartphones

MP3 Players

Personal Media Players

Handheld Gaming

Consoles

Notebook Computers

Applications

PART PIN-PACKAGE TEMP RANGE

MAX9788EWP+TG45 20 WLP -40°C to +85°C

MAX9788ETI+ 28 TQFN-EP* -40°C to +85°C

Denotes a lead-free package.

T = Tape and reel.

G45 indicates protective die coating.

EP = Exposed pad.

Summary of content (13 pages)

PAGE 1
9-0710; Rev 3; 5/08 KIT ATION EVALU E L B AVAILA 14VP-P, Class G Ceramic Speaker Driver Features The MAX9788 features a mono Class G power amplifier with an integrated inverting charge-pump power supply specifically designed to drive the high capacitance of a ceramic loudspeaker. The charge pump can supply greater than 700mA of peak output current at 5.5VDC, guaranteeing an output of 14VP-P. The MAX9788 maximizes battery life by offering highperformance efficiency.
PAGE 2
MAX9788 14VP-P, Class G Ceramic Speaker Driver ABSOLUTE MAXIMUM RATINGS CPVDD, CPGND, C1P, C1N, PVSS .................................800mA Any Other Pin ..................................................................20mA Continuous Power Dissipation (TA = +70°C) 20-Bump WLP (derate 10.3mW/°C above +70°C) (Note 1)..................................................827mW 28-Pin TQFN (derate 20.8mW/°C above +70°C) ........1667mW Operating Temperature Range ...........................
PAGE 3
14VP-P, Class G Ceramic Speaker Driver (VCC = VCPVDD = V SHDN = 3.6V, VGND = VCPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF; load connected between OUT+ and OUT-, ZLOAD = 10Ω + 1µF, unless otherwise stated; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 2, 3) PARAMETER Output Voltage SYMBOL VOUT Continuous Output Power POUT CONDITIONS f = 10kHz, 1% THD+N, ZL = 1µF + 10Ω, no load 1% THD+N, f = 1kHz, RL = 8Ω PSRR 6.
PAGE 4
Typical Operating Characteristics (VCC = VCPVDD = V SHDN = 3.6V, VGND = VCPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF, ZL = 1µF + 10Ω; load terminated between OUT+ and OUT-, unless otherwise stated; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 1, 2) TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY VCC = 2.7V VCC = 3.6V 0.1 VOUT = 1.25VRMS THD+N (%) THD+N (%) 0.1 VOUT = 1.9VRMS 0.01 0.001 0.
PAGE 5
14VP-P, Class G Ceramic Speaker Driver POWER CONSUMPTION vs. OUTPUT VOLTAGE MAX9788 toc12 MAX9788 toc11 MAX9788 toc10 300 SHDN 5V/div SHDN 5V/div OUT+ - OUT500mV/div OUT+ - OUT500mV/div 250 200 150 100 VCC = 5V fIN = 1kHz 1% THD+N 50 0 1 2 3 4 5 7 6 10ms/div 10ms/div OUTPUT VOLTAGE (VRMS) SUPPLY CURRENT vs. SUPPLY VOLTAGE CLASS G OUTPUT WAVEFORM MAX9788 toc13 MAX9788 toc14 12 10 SUPPLY CURRENT (mA) OUT+ 5V/div OUT5V/div OUT+ - OUT10V/div 8 6 4 2 1% THD+N 0 2.5 200μs/div 3.0 3.
PAGE 6
Typical Operating Characteristics (continued) (VCC = VCPVDD = V SHDN = 3.6V, VGND = VCPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 = 10µF, ZL = 1µF + 10Ω; load terminated between OUT+ and OUT-, unless otherwise stated; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 1, 2) VCC = 3.6V 6 VOUT = 2VRMS 18 16 14 GAIN (dB) 5 4 3 VCC = 2.7V 12 10 8 6 2 4 1 2 0 0 100 10 1k 10k 100k MAX9788 toc19 3.
PAGE 7
14VP-P, Class G Ceramic Speaker Driver As the output signal increases so a wider supply is needed, the device begins its transition to the higher supply range (VCC to SVSS) for the large signals. To ensure a seamless transition between the low and high supply ranges, both of the lower transistors are on so that: ILOAD = IN1 + IN2 As the output signal continues to increase, the transition to the high supply is complete.
PAGE 8
MAX9788 14VP-P, Class G Ceramic Speaker Driver Inverting Charge Pump The MAX9788 features an integrated charge pump with an inverted supply rail that can supply greater than 700mA over the positive 2.7V to 5.5V supply range. In the case of the MAX9788, the charge pump generates the negative supply rail (PVSS) needed to create the higher supply range, which allows the output of the device to operate over a greater dynamic range as the battery supply collapses over time.
PAGE 9
14VP-P, Class G Ceramic Speaker Driver Component Selection Input-Coupling Capacitor The AC-coupling capacitors (CIN_) and input resistors (RIN_) form highpass filters that remove any DC bias from an input signal (see the Functional Diagram/ Typical Operating Circuit). CIN_ blocks DC voltages from the amplifier input. The -3dB point of the highpass filter, assuming zero source impedance due to the input signal source, is given by: The MAX9788 is ideal for driving a capacitive ceramic speaker.
PAGE 10
Hold Capacitor (C2) The output capacitor value and ESR directly affect the ripple at PVSS. Increasing C2 reduces output ripple. Likewise, decreasing the ESR of C2 reduces both ripple and output resistance. A 10µF capacitor is recommended. Charge-Pump Frequency Set Resistor (RFS) The charge pump operates in two modes. When the charge pump is loaded below 100mA, it operates in a slow mode where the oscillation frequency is reduced to 1/4 of its normal operating frequency.
PAGE 11
14VP-P, Class G Ceramic Speaker Driver VDD SHDN CONTROL SIGNAL 0.1μF * 20kΩ 14, 22 (D1, D5) 4 (A3) 1 (B2) VCC SHDN CPVDD 12 (B4) FB+ MAX9788 CIN 0.47μF RIN+ 10kΩ RFB+ 10kΩ OUT+ 20 (D2) 10 (B5) IN+ + 9 (A5) INRIN10kΩ CIN 0.47μF CLASS G OUTPUT STAGE - RL 10Ω OUT- 16 (D4) RFB10kΩ GND 18 (D3) ( ) WLP PACKAGE FS 13 (C5) CHARGE PUMP 7 (A4) FBCPGND 27 (A1) C1P C1N 26 (B1) PVSS 3 (A2) 24 (C1) C1 4.
PAGE 12
14VP-P, Class G Ceramic Speaker Driver MAX9788 Pin Configurations TOP VIEW (BUMP SIDE DOWN) N.C. CPGND C1N N.C. PVSS N.C. VCC 27 26 25 24 23 22 + 28 TOP VIEW MAX9788 SHDN 1 21 SVSS N.C. 2 20 OUT+ C1P 3 19 N.C. CPVDD 4 18 GND N.C. 5 17 N.C. N.C. 6 16 OUT- 15 SVSS 8 9 10 11 12 13 14 IN- IN+ N.C. FB+ FS VCC 7 EP* N.C.
PAGE 13
14VP-P, Class G Ceramic Speaker Driver REVISION NUMBER REVISION DATE 0 12/06 Initial release 1 11/07 Include tape and reel note, edit Absolute Maximum Ratings, update TQFN package outline 2 2/08 Replaced USCP with WLP package throughout data sheet including new WLP package outline, added new TOC 19 and Note 1 3 5/08 Updated Typical Application Circuit and corrected stylistic errors DESCRIPTION PAGES CHANGED — 1, 2,13, 14 1, 2, 3, 6, 10, 11, 12, 15, 16 1–6, 11 Maxim cannot assume responsibili