MAX8821 MAXIM [Maxim Integrated Products], MAX8821 Datasheet

MAX8821

Manufacturer Part Number

MAX8821

Description

White LED Charge Pump with Mono Class D Audio Amp and Dual LDO

Manufacturer

MAXIM [Maxim Integrated Products]

Datasheet

1.MAX8821.pdf (29 pages)

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The MAX8821 integrates a charge pump for white

LEDs, an audio loudspeaker amplifier, and two low-

noise LDOs controlled by an I

high-efficiency, adaptive-mode inverting charge pump

drives up to six LEDs with constant current for uniform

brightness. The LED current is controlled by an I

interface and adjusts from 0.1mA to 25.6mA per LED

into 32 pseudo-logarithmic steps. Independent volt-

ages for each LED maximize efficiency even with large

LED forward voltage (V

ature derating function reduces the current above

+40°C to protect the LEDs.

The high-efficiency mono Class D audio amplifier deliv-

ers up to 2W into a 4Ω speaker from a 5V input supply.

The amplifier features proprietary filterless Active

Emissions Limiting (AEL) technology. AEL prevents

high-frequency emissions resulting from conventional

Class D free-wheeling behavior in the presence of an

inductive load. The amplifier offers two modulation

schemes: a fixed-frequency mode (FFM) and a spread-

spectrum mode (SSM) that reduce EMI-radiated emis-

sions due to the modulation frequency. The amplifier

also has robust output protection and high power-sup-

ply rejection ratio (PSRR). Click-and-pop suppression is

active during power-up/down, enable/disable, and for

all mode changes. The amplifier’s gain is adjustable

through an I

steps. Differential inputs improve common-mode noise

rejection.

The LDOs in the MAX8821 are designed for low-noise

operation. Each LDO output voltage can be individually

programmed by the I

LDO2 have a high 70dB PSRR rating.

The MAX8821 includes soft-start, thermal shutdown,

open-circuit, and short-circuit protections, and is avail-

able in a compact 28-pin, Thin QFN, 4mm x 4mm pack-

age (0.8mm max height).

19-1014; Rev 0; 10/07

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.

Cell Phones and Smartphones

PDAs, Digital Cameras, Camcorders

MP3 Players, GPS Devices

White LED Charge Pump with Mono Class D

C interface, from -3dB to +24dB in 10 3dB

________________________________________________________________ Maxim Integrated Products

General Description

) mismatch. An internal temper-

C interface. Both LDO1 and

C control interface. The

Applications

Audio Amp and Dual LDO

♦ White LED Inverting Charge Pump

♦ Mono 2W Class D Loudspeaker Amplifier

♦ Dual Low-Noise LDO

+ Denotes a lead-free package.

MAX8821ETI+

CONTROL AND I

2.7 TO 5.5V

Independent Adaptive Current Regulators for

6 Low-Dropout Current Regulators

Flexible I

Ramp-Up/Down, Current Control for Each LED

Low 70µA (typ) Quiescent Current

85% Efficiency (R

Low 0.05% THD+N at 1kHz

High 65dB PSRR at 1kHz

Fully Differential Inputs

-3dB to +24dB Gain Settings in 3dB Steps

Integrated Click-and-Pop Suppression

Low Quiescent Current

45µV

Flexible I

200mA and 300mA Output Current Drive

PART

DIFFERENTIAL

INPUT

AUDIO INPUT

INTERFACE

Each LED

LOGIC

Derating Function Protects LEDs

RMS

Output Noise, 70dB PSRR

C Dimming Control for Each LED

C-Controlled Output Voltages

Typical Operating Circuit

-40°C to +85°C

IN3

CMREF

SCL

IN1

PGND1

IN2

PGND2

AGND

REF

SDA

AIN+

AIN-

TEMP RANGE

C1P

Ordering Information

C1N

MAX8821

= 8Ω, P

C2P

C2N

PIN-

PACKAGE

28 Thin QFN

4mm x 4mm

OUT

LDO2

LED2

LED3

LED4

LED5

LED6

LDO1

SPK+

SPK-

LED1

NEG

= 600mW)

Features

LOUDSPEAKER/

EARPIECE

DUAL LOW

NOISE LDO

INDIVIDUAL

0.1mA TO

25.6mA

DIMMING

T2844-1

CODE

PKG

Related parts for MAX8821

MAX8821 Summary of contents

Page 1

... I C interface, from -3dB to +24dB in 10 3dB steps. Differential inputs improve common-mode noise rejection. The LDOs in the MAX8821 are designed for low-noise operation. Each LDO output voltage can be individually 2 programmed by the I C interface. Both LDO1 and LDO2 have a high 70dB PSRR rating. ...

Page 2

White LED Charge Pump with Mono Class D Audio Amp and Dual LDO ABSOLUTE MAXIMUM RATINGS IN1, IN2, IN3 AGND..................................-0.3V to +6.0V DD SCL, SDA to AGND ....................................-0. IN1, IN2, IN3 to NEG .............................................-0.3V to +6.0V ...

Page 3

White LED Charge Pump with Mono Class D ELECTRICAL CHARACTERISTICS (continued 3.6V, V IN1 IN2 IN3 DD AGND Typical values are +25°C.) (Note 1) A PARAMETER Soft-Start Time Regulation ...

Page 4

White LED Charge Pump with Mono Class D Audio Amp and Dual LDO ELECTRICAL CHARACTERISTICS (continued 3.6V, V IN1 IN2 IN3 DD AGND Typical values are +25°C.) (Note 1) ...

Page 5

White LED Charge Pump with Mono Class D ELECTRICAL CHARACTERISTICS (continued 3.6V, V IN1 IN2 IN3 DD AGND Typical values are +25°C.) (Note 1) A PARAMETER R = 8Ω, ...

Page 6

White LED Charge Pump with Mono Class D Audio Amp and Dual LDO ELECTRICAL CHARACTERISTICS (continued 3.6V, V IN1 IN2 IN3 DD AGND Typical values are +25°C.) (Note 1) ...

Page 7

White LED Charge Pump with Mono Class D ELECTRICAL CHARACTERISTICS (continued 3.6V, V IN1 IN2 IN3 DD AGND Typical values are +25°C.) (Note 1) A PARAMETER I = 50mA ...

Page 8

White LED Charge Pump with Mono Class D Audio Amp and Dual LDO ELECTRICAL CHARACTERISTICS (continued 3.6V, V IN1 IN2 IN3 DD AGND Typical values are +25°C.) (Note 1) ...

Page 9

... ALL LEDs ON 25.6mA LED 0A 400ns/div LED LINE TRANSIENT WITH MODE CHANGE (V = 4.2V TO 3.8V TO 4.2V 200mA/div 0A 20mA/div I LED6 0A ALL LEDs AT 25.6mA SETTING 1ms/div LED RAMP-UP AC-COUPLED 50mV/div I LED6 50mA/div 0A 20mA/div I LED5 0A 400ms/div MAX8821 toc11 4.2V 3.8V 200mA/div 0A 20mA/div 0A MAX8821 toc14 10mA/div 0A 10mA/div 0A 9 ...

Page 10

White LED Charge Pump with Mono Class D Audio Amp and Dual LDO ( 3.6V, V IN1 IN2 IN3 DD AGND TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 3.6V IN ...

Page 11

White LED Charge Pump with Mono Class 3.6V, V IN1 IN2 IN3 DD AGND WIDEBAND OUTPUT SPECTRUM FIXED-FREQUENCY MODE INPUTS AC GROUNDED -20 -40 -60 -80 -100 -120 ...

Page 12

... LDO2 -20 -30 - 100mA -50 LDO2 -60 -70 -80 -90 0. +25°C, unless otherwise noted.) A SHUTDOWN WAVEFORMS MAX8821 toc31 1V/div 0V 1V/div 0dB V LDO OUTPUT VOLTAGE ACCURACY vs. LOAD CURRENT V = 2.8V LDO2 V = 2.8V LDO1 50 100 150 200 250 300 LOAD CURRENT (mA) LDO PSRR vs ...

Page 13

... MAX8821 toc40 V LDO1 V LDO2 2ms/div = +25°C, unless otherwise noted.) A LDO LINE TRANSIENT (V = 3.6V TO 4.5V) IN3 MAX8821 toc37 4.5V 3.6V AC-COUPLED 10mV/div AC-COUPLED 10mV/div I = 150mA 100mA LDO1 LDO2 200μs/div LDO2 LOAD TRANSIENT MAX8821 toc39 AC-COUPLED 50mV/div 50mA/div 0A 10μs/div 1V/div 0V 1V/div 0V 13 ...

Page 14

White LED Charge Pump with Mono Class D Audio Amp and Dual LDO PIN NAME Input Supply Voltage. The control. Drive V Audio Common-Mode Reference Voltage. Bypass CMREF with a 0.1µF ceramic capacitor ...

Page 15

... IN3 AIN+ + PGA AIN- - PGND2 Figure 1. Block Diagram ______________________________________________________________________________________ Audio Amp and Dual LDO C1P C1N C2P C2N INVERTING CHARGE PUMP NEG REGULATORS MAX8821 CURRENT SOURCE CONTROL NEG NEG NEG NEG NEG OSCILLATOR CLASS D AMP REF PGND2 EP NEG SELECT ADAPTIVE MINIMUM ...

Page 16

... DIFFERENTIAL AUDIO INPUT Figure 2. Typical Application Circuit Detailed Description The MAX8821 integrates a charge pump for white LED display backlighting, an audio loudspeaker amplifier, and dual LDO for camera functions. It includes soft- start, thermal shutdown, open-circuit and short-circuit protections for the white LEDs, audio amplifier, and LDOs ...

Page 17

... Each current LED_ is internally connected to ground and the charge IN pump is enabled. To disable the corresponding current regulator, short any unused LED_ to IN1. The MAX8821 contains special circuitry to detect this condition and disables the corresponding current regulator to avoid wasting battery power. The MAX8821 contains a derating function that auto- ...

Page 18

... White LED Charge Pump with Mono Class D Audio Amp and Dual LDO The audio amplifier in the MAX8821 Class D loudspeaker amplifier. The amplifier features a low- power shutdown mode and industry-leading click-and- pop suppression. The amplifier also features a programmable gain control through an I The amplifier operates from a single 2 ...

Page 19

... The linear regulators are designed for low dropout and low quiescent current to maximize battery life. Both 2 LDOs are controlled through the I ing the number of control lines to the MAX8821. Each LDO has an individual control register (LDO1_CNTL and LDO2_CNTL, Tables 13 and 14). The I controls the output voltages, and the enable/disable state for both LDO1 and LDO2 ...

Page 20

White LED Charge Pump with Mono Class D Audio Amp and Dual LDO LOW HIGH SCL SDA SU_STA HD_STA SU_DAT A = START CONDITION B = MSB OF ADDRESS CLOCKED INTO SLAVE C ...

Page 21

White LED Charge Pump with Mono Class D Table 2. LED1_CNTL (Address 0x00) BIT NAME CODE B7, B6 N/A, do not use. LED1 ramp-up/down 0 disabled. B5 LED1_RP_EN 1 LED1 ramp-up/down enabled. 00000 00001 00010 00011 00100 00101 00110 00111 ...

Page 22

White LED Charge Pump with Mono Class D Audio Amp and Dual LDO Table 4. LED3_CNTL (Address 0x02) BIT NAME CODE B7, B6 N/A, do not use. LED3 ramp-up/down 0 disabled. B5 LED3_RP_EN 1 LED3 ramp-up/down enabled. 00000 00001 00010 ...

Page 23

White LED Charge Pump with Mono Class D Table 6. LED5_CNTL (Address 0x04) BIT NAME CODE B7, B6 N/A, do not use. LED5 ramp-up/down 0 disabled. B5 LED5_RP_EN 1 LED5 ramp-up/down enabled. 00000 00001 00010 00011 00100 00101 00110 00111 ...

Page 24

White LED Charge Pump with Mono Class D Audio Amp and Dual LDO Table 8. RAMP1_CNTL (Address 0x06) BIT NAME B7, B6 LED1_RU[1:0] B5, B4 LED1_RD[1:0] B3, B2 LED2_RU[1:0] B1, B0 LED2_RD[1:0] Notes defaults ...

Page 25

White LED Charge Pump with Mono Class D Table 11. BLINK_CNTL (Address 0x09) BIT NAME CODE 00 01 B7, B6 LED5_OFF_BLINK B5, B4 LED5_ON_BLINK B3, B2 LED6_OFF_BLINK B1, ...

Page 26

White LED Charge Pump with Mono Class D Audio Amp and Dual LDO Table 14. LDO2_CNTL (Address 0x0C) BIT NAME CODE B7, B6 N/A, do not use. 0 LDO2 is disabled. B5 LDO2_EN 1 LDO2 is enabled. Active pulldown enabled ...

Page 27

... If PCB. Connect the exposed paddle to AGND directly the amplifier is not under the IC. Refer to the MAX8821 Evaluation Kit for enabled, the charge an example of a PCB layout. pump automatically switches between 1x mode and 1 ...

Page 28

White LED Charge Pump with Mono Class D Audio Amp and Dual LDO (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) 28 ______________________________________________________________________________________ Package Information ...

Page 29

White LED Charge Pump with Mono Class D (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) Maxim cannot assume responsibility for use of any circuitry ...

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