Evaluates: MAX9728A/MAX9728B 19-3921 Rev 0 12/05 MAX9728A Evaluation Kit General Description Features The MAX9728A evaluation kit (EV kit) is a fully assem- No Bulky DC-Blocking Capacitors Required bled and tested surface-mount circuit board that evalu- 2.7V to 5.5V DC Single-Supply Operation ates the MAX9728A DirectDrive stereo headphone amplifier. Maxims DirectDrive technology eliminates 63mW Per Channel into 32 (V = 5V) DD the need for DC-blocking capacitors on the stereo out- Low 0.02% THD+N at 1kHz puts of the amplifier. Designed to operate from a 2.7V to 5.5V DC power supply, the EV kit is capable of deliv- High 86dB PSRR Eliminates LDO ering up to 42mW per channel into a 16 load or 63mW 2V Audio Line Driver from a Single 3.3V RMS per channel into a 32 load at 1% THD+N (V = 5V). DD Supply The EV kit can be configured as a line driver to deliver 2V into a 10k load from a single 3.3V DC supply. RMS Fully Assembled and Tested Surface-Mount Board The MAX9728A EV kit also evaluates the MAX9728B IC. Ordering Information PART TEMP RANGE IC PACKAGE MAX9728AEVKIT 0C to +70C 12 Thin QFN Note: To evaluate the MAX9728B, request a MAX9728BETC+ free sample with the MAX9728AEVKIT. Component List DESIGNATION QTY DESCRIPTION DESIGNATION QTY DESCRIPTION 1.0F 10%, 10V X7R ceramic E4, E10 2 0 resistors (0603) capacitors (0603) E5, E6, E11, E12 0 Not installed (0603) C1, C2, C3 3 TDK C1608X7R1A105K Stereo headphone jack Taiyo Yuden LMK107BJ105KA J1 1 (3.5mm dia.) 10F 20%, 6.3V X5R ceramic JU1 1 3-pin header capacitor (0805) C4* 1 MAX9728AETC+ (12-pin TQFN, TDK C2012X5R0J106M U1 1 3mm x 3mm x 0.8mm) Taiyo Yuden JMK212BJ106MG E1, E7 2 15k 1% resistors (0603) 1 Shunt E2, E8 2 30.1k 1% resistors (0603) 1 MAX9728A EV kit PC board 0.47F 10%, 6.3V X7R ceramic E3, E9 2 capacitors (0603) TDK C1608X5R0J474K *System-level requirement. Component Suppliers SUPPLIER PHONE FAX WEBSITE AVX 843-946-0238 843-626-3123 www.avxcorp.com Taiyo Yuden 800-348-2496 847-925-0899 www.t-yuden.com TDK 847-803-6100 847-390-4405 www.component.tdk.com Note: Indicate that you are using the MAX9728A when contacting these component suppliers. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.MAX9728A Evaluation Kit The MAX9728A EV kit can be used to evaluate the Quick Start MAX9728B, fixed-gain, DirectDrive stereo headphone Recommended Equipment amplifier. To evaluate the MAX9728B, request a One pair of 16 or 32 headphones MAX9728BETC free sample with the MAX9728AEVKIT (see the Evaluating the MAX9728B section for more One DC power supply capable of supplying between details). 2.7V and 5.5V at 500mA One stereo audio source Shutdown Control Jumper JU1 controls the shutdown pin (SHDN) of the Procedures MAX9728A IC. See Table 1 for jumper shunt positions. The MAX9728A EV kit is fully assembled and tested. Follow the steps below to verify board operation. Do Table 1. Jumper JU1 Shutdown Selection not turn on the power supply until all connections are completed: SHUNT POSITION DESCRIPTION 1) Verify that a shunt is installed across pins 1 and 2 of 1-2 Amplifier enabled jumper JU1. 2-3 Amplifier disabled 2) Plug the headphones into the 3.5mm headphone jack. 3) Ensure that the stereo audio source is turned off. Layout Considerations 4) Connect the disabled audio source between IN and To optimize the audio performance of the MAX9728A, it GND. is important to follow these layout guidelines. The MAX9728A EV kit implements two ground planes to 5) Connect the 2.7V to 5.5V DC power supply to the minimize the amount of charge-pump switching noise VDD and GND pads. coupled into the audio signal. The two planes are star- 6) Turn on the DC power supply. connected at one point (GND pad). Place capacitors 7) Enable the stereo audio source. C1, C2, and C3 as close to the IC as possible. Use short, wide traces to connect the power pins of the IC Detailed Description to the power supply. The MAX9728A EV kit evaluates the MAX9728A Evaluating the MAX9728B adjustable gain, DirectDrive stereo headphone amplifier. The MAX9728A EV kit can evaluate the MAX9728B. The The MAX9728A EV kit is configured with an external gain MAX9728B is a -1.5V/V fixed-gain version of the of -2V/V and can be powered from a 2.7V to 5.5V DC MAX9728A. To evaluate the MAX9728B, replace U1 with single supply. The MAX9728A is designed to drive a MAX9728BETC+ IC and replace the components as 42mW per channel into a 16 load or 63mW per chan- outlined in Table 2. The MAX9728B IC can only be eval- nel into a 32 load at 1% THD+N (V = 5V). DD uated in the headphone amplifier configuration. The EV kit can also be configured as an audio line driver to drive 2V into a 10k load from a single supply. An RMS Table 2. Component Values for active lowpass filter can be implemented with the Evaluating the MAX9728B MAX9728A (see the MAX9728A as a Lineout Amplifier section). All passive components recommended for a line COMPONENT MAX9728A MAX9728B driver configuration are included in the MAX9728A EV kit E1, E7 15k resistors 0 resistors pack-out BOM. E2, E8 30.1k resistors Open 2 Evaluates: MAX9728A/MAX9728B