Analog Devices Inc./Maxim Integrated

The MAX97200 is a 45mW Class H headphone amplifier that runs from a single low 1.8V supply voltage and employs Maxim's second-generation DirectDrive® technology.The MAX97200 features a Dual Mode™ internal charge pump to generate the power rails for the amplifier. The charge-pump output can be ±PVIN/2 or ±PVIN depending on the amplitude of the output signal. When the output voltage is low, the power-supply voltage is ±PVIN/2. When the output signal demands larger output voltage, the charge pump switches modes so that a greater power-supply voltage is realized and more output power can be delivered to the load.Second-generation DirectDrive technology improves power consumption when compared to first-generation DirectDrive amplifiers. The MAX97200 can be powered from a regulated 1.8V and have similar power consumption to a traditional DirectDrive amplifier that is powered from 0.9V.Maxim's DirectDrive architecture uses an inverting charge pump to derive a negative voltage supply. The headphone amplifier is powered between the positive supply and the generated negative rail. This scheme allows the audio output signal to be biased about ground, eliminating the need for large DC-blocking capacitors between the amplifier output and the headphone load.Low-output offset voltage provides very good click-and-pop performance both into and out of shutdown. High signal-to-noise ratio maintains system fidelity.The MAX97200 is available in a tiny, 12-bump wafer level packaging (WLP 1.27mm x 1.65mm) with a small, 0.4mm lead pitch and specified over the -40°C to +85°C extended temperature range.ApplicationsCellular PhonesMP3 PlayersSmartphonesVoIP Phones

The MAX9722A/MAX9722B stereo headphone amplifiers are designed for portable equipment where board space is at a premium. The MAX9722A/MAX9722B use a unique DirectDrive® architecture to produce a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors, which saves cost, board space, and component height. Additionally, the gain of the amplifier is set internally (-2V/V, MAX9722B) or adjusted externally (MAX9722A). The MAX9722A/MAX9722B deliver up to 70mW per channel into a 16Ω load or 130mW into a 32Ω load and have low 0.009% THD+N. An 80dB at 217Hz power-supply rejection ratio (PSRR) allows these devices to operate from noisy digital supplies without an additional linear regulator. The MAX9722A/MAX9722B include ±8kV ESD protection on the headphone outputs. Comprehensive anticlick-and-pop circuitry suppresses audible clicks and pops on startup and shutdown. A low-power shutdown mode reduces the supply current to 0.1µA.The MAX9722A/MAX9722B operate from a single 2.4V to 5.5V supply, consume only 5.5mA of supply current, feature short-circuit and thermal-overload protection, and are specified over the extended -40°C to +85°C temperature range. The devices are available in tiny 16-pin thin QFN (3mm x 3mm x 0.8mm) and 16-pin TSSOP packages.ApplicationsCell PhonesFlat-Panel MonitorsMP3 PlayersNotebook and Desktop PCsPDAsPortable Audio EquipmentSmartphones

The MAX97220 is a differential input DirectDrive® line driver/headphone amplifier. This device is capable of driving line level loads with 3VRMSinto 1kΩ with a 5V supply and 2VRMSinto 600Ω loads from a 3.3V supply. A headphone load is capable of being driven with 125mW into 32Ω with a 5V supply. The IC is offered with an internally fixed 6dB gain or an externally set gain through external resistors. The external gain setting nodes can also be used to configure filters for set-top box applications. The IC has exceptional THD+N over the full audio bandwidth.Two versions of the IC are available with different turn-on times (tON). The A, C, and E versions for headphone applications feature a tONof 5.5ms while the B and D versions, intended for set-top-box applications, feature a 130ms tON. An on-chip charge pump inverts the power-supply input, creating a negative rail. The output stage of the amplifier is powered between the positive input supply and the output of the charge pump. The bipolar supplies bias the output about ground, eliminating the need for large, distortion-introducing output coupling capacitors. The IC powers on and off without clicks or pops.The IC is available in a 3mm x 3mm x 0.8mm, 16-pin TQFN and is specified over the extended -40°C to +85°C temperature range.ApplicationsBlu-ray™ and DVD PlayersLCD TelevisionsProsumer Audio DevicesSet-Top BoxesSimple Multimedia Interfaces

The MAX9723 stereo DirectDrive headphone amplifier with BassMax and volume control is ideal for portable audio applications where space is at a premium and performance is essential. The MAX9723 operates from a single 1.8V to 3.6V power supply and includes features that reduce external component count, system cost, board space, and improves audio reproduction.The headphone amplifier uses Maxim's DirectDrive architecture that produces a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors. The headphone amplifiers deliver 62mW into a 16Ω load, feature low 0.006% THD+N, and high 90dB PSRR. The MAX9723 features Maxim's industry-leading click-and-pop suppression.The BassMax feature boosts the bass response of the amplifier, improving audio reproduction when using inexpensive headphones. The integrated volume control features 32 discrete volume levels, eliminating the need for an external potentiometer. BassMax and the volume control are enabled through the I²C/SMBus™-compatible interface. Shutdown is controlled through either the hardware or software interfaces.The MAX9723 consumes only 3.7mA of supply current at 1.8V, provides short-circuit and thermal-overload protection, and is fully specified over the extended -40°C to +85°C temperature range. The MAX9723 is available in a tiny (2mm x 2mm x 0.62mm) 16-bump chip-scale package (UCSP™) or 16-pin thin QFN (4mm x 4mm x 0.8mm) package.ApplicationsMini Disc PlayersMP3 PlayersMP3-Enabled Cellular PhonesPDA AudioPortable CD Players

The MAX9724A/MAX9724B stereo headphone amplifiers are designed for portable equipment where board space is at a premium. These devices use a unique DirectDrive® 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 MAX9724 suppresses RF radiation received by input and supply traces acting as antennas and prevents the amplifier from demodulating the coupled noise. The MAX9724A offers an externally adjustable gain while the MAX9724B has an internally preset gain of -1.5V/V. The MAX9724A/MAX9724B deliver up to 60mW per channel into a 32Ω load and have low 0.02% THD+N. An 80dB at 1kHz power-supply rejection ratio (PSRR) allows these devices to operate from noisy digital supplies without an additional linear regulator. Comprehensive click-and-pop circuitry suppresses audible clicks and pops on startup and shutdown.The MAX9724A/MAX9724B operate from a single 2.7V to 5.5V supply, consume only 3.5mA of supply current, feature short-circuit and thermal-overload protection, and are specified over the extended -40°C to +85°C temperature range. The devices are available in tiny 12-bump UCSP™ (1.5mm x 2mm) and 12-pin thin QFN (3mm x 3mm x 0.8mm) packages.ApplicationsCellular PhonesDVD PlayersHandheld Gaming ConsolesMP3 PlayersNotebook PCsPDAsSmartphones

The MAX9725A–MAX9725D fixed-gain, stereo headphone amplifiers are ideal for portable equipment where board space is at a premium. The MAX9725E offers the flexibility to adjust the gain with external input and feedback resistors. The MAX9725A–MAX9725E use a unique DirectDrive® 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. Fixed gains of -2V/V (MAX9725A), -1.5V/V (MAX9725B), -1V/V (MAX9725C), and -4V/V (MAX9725D) further reduce external component count. The adjustable gain of the MAX9725E DirectDrive headphone amplifier allows for any gain down to -1V/V using external resistors.The MAX9725 delivers up to 20mW per channel into a 32Ω load and achieves 0.006% THD+N. An 80dB at 1kHz power-supply rejection ratio (PSRR) allows the MAX9725 to operate from noisy digital supplies without an additional linear regulator. The MAX9725 includes ±8kV ESD protection on the headphone output. Comprehensive click-and-pop circuitry suppresses audible clicks and pops at startup and shutdown. A low-power shutdown mode reduces supply current to 0.6µA (typ).The MAX9725 operates from a single 0.9V to 1.8V supply, allowing the device to be powered directly from a single AA or AAA battery. The MAX9725 consumes only 2.1mA of supply current, provides short-circuit protection, and is specified over the extended -40°C to +85°C temperature range. The MAX9725 is available in a tiny (1.54mm x 2.02mm x 0.6mm) 12-bump chip-scale package (UCSP™) and a 12-pin thin QFN package (4mm x 4mm x 0.8mm).ApplicationsCell PhonesMP3 PlayersPDAsPortable Audio EquipmentSmartphones