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| ASAHI KASEI [AK4550] Low Power & Small Package 16bit CODEC GENERAL DESCRIPTION The AK4550 is a low voltage 16bit A/D & D/A converter for portable digital audio system. In the AK4550, the loss of accuracy form clock jitter is also improved by using SCF techniques for on-chip post filter. Analog signal input/output of the AK4550 are single-ended, therefore, any external filters are not required. The AK4550 is suitable for portable digital audio system, as the AK4550 is lower power dissipation and a smaller package than AK4518. FEATURES o HPF for DC-offset cancel (fc=3.4Hz) o Single-ended ADC - S/(N+D): 82dB@VDD=2.5V - Dynamic Range, S/N: 89dB@VDD=2.5V o Single-ended DAC - Digital de-emphasis for 32kHz, 44.1kHz, 48kHz sampling - S/(N+D): 85dB@VDD=2.5V - Dynamic Range, S/N: 92dB@VDD=2.5V o Audio I/F format: MSB First, 2's Compliment (AK4518 compatible) - ADC: 16bit MSB justified - DAC: 16bit LSB justified o Input/Output Voltage: 0.6 X VDD (=1.5Vpp@VDD=2.5V) o High Jitter Tolerance o Sampling Rate: 8kHz to 50kHz o Master Clock: 256fs or 384fs or 512fs o Power Supply: 2.3 to 3.6V o Low Power Supply Current: 10mA o Ta = -40 to 85C o Very Small Package: 16pin TSSOP VDD VSS Modulator Modulator Common Voltage Modulator Modulator 8X Interpolator 8X Interpolator PWDA PWAD Decimation Filter Decimation Filter Serial I/O Interface Clock Divider MCLK LRCK SCLK SDTO SDTI DEM0 AOUTL LPF DEM1 AK4550 AINL AINR VCOM AOUTR LPF M0068-E-01 -1- 2000/4 ASAHI KASEI [AK4550] n Ordering Guide AK4550VT AKD4550 -40 +85C 16pin TSSOP (0.65mm pitch) Evaluation Board for AK4550 n Pin Layout VCOM AINR AINL VSS VDD DEM0 DEM1 SDTO 1 2 3 4 5 6 7 8 16 15 14 AOUTR AOUTL PWDA PWAD SCLK MCLK LRCK SDTI Top View 13 12 11 10 9 PIN/FUNCTION No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Pin Name VCOM AINR AINL VSS VDD DEM0 DEM1 SDTO SDTI LRCK MCLK SCLK PWAD PWDA AOUTL AOUTR I/O O I I I I O I I I I I I O O Function Common Voltage Output Pin, 0.45 x VDD Rch Analog Input Pin Lch Analog Input Pin Ground Pin Power Supply Pin De-emphasis Control Pin De-emphasis Control Pin Audio Serial Data Output Pin Audio Serial Data Input Pin Input/Output Channel Clock Pin Master Clock Input Pin Audio Serial Data Clock Pin ADC Power-Down & Reset Mode Pin "L": Power down. ADC should always be reset upon power-up. DAC Power-Down & Reset Mode Pin "L": Power down. DAC should always be reset upon power-up. Lch Analog Output Pin Rch Analog Output Pin M0068-E-01 -2- 2000/4 ASAHI KASEI [AK4550] ABSOLUTE MAXIMUM RATINGS (VSS=0V; Note 1) Parameter Power Supply Input Current (Any Pin Except Supplies) Input Voltage Ambient Temperature (power applied) Storage Temperature Note:1. All voltages with respect to ground. Symbol VDD IIN VIN Ta Tstg min -0.3 -0.3 -40 -65 max 4.6 10 VDD+0.3 85 150 Units V mA V C C WARNING: Operation at or beyond these limits may results in permanent damage to the device. Normal operation is not guaranteed at these extremes. RECOMMENDED OPERATING CONDITIONS (VSS=0V; Note 1) Parameter Power Supply Symbol VDD min 2.3 typ 2.5 max 3.6 Units V Note:1. All voltages with respect to ground. *AKM assumes no responsibility for the usage beyond the conditions in this data sheet. M0068-E-01 -3- 2000/4 ASAHI KASEI [AK4550] ANALOG CHARACTERISTICS (Ta=25C; VDD=2.5V; fs=44.1kHz; Signal Frequency=1kHz; SCLK=64fs; Measurement frequency=10Hz 20kHz; unless otherwise specified) Parameter min typ max Units ADC Analog Input Characteristics: Analog Source Impedance=470 (Note 2) Resolution 16 Bits S/(N+D) (-0.5dB Input) 72 82 dB D-Range (-60dB Input, A-weighted) 82 89 dB S/N (A-weighted) 82 89 dB Interchannel Isolation 80 95 dB Interchannel Gain Mismatch 0.2 0.5 dB Input Voltage (Note 3) 1.35 1.50 1.65 Vpp Input Resistance 50 100 k Power Supply Rejection (Note 4) 35 dB DAC Analog Output Characteristics: (Note 5) Resolution 16 Bits S/(N+D) 75 85 dB D-Range (-60dB Output, A-weighted) 86 92 dB S/N (A-weighted) 86 92 dB Interchannel Isolation 80 95 dB Interchannel Gain Mismatch 0.2 0.5 dB Output Voltage (Note 3) 1.35 1.50 1.65 Vpp Load Resistance 10 k Load Capacitance 30 pF Power Supply Rejection (Note 4) 50 dB Power Supplies Power Supply Current 10 15 mA AD+DA PWAD = "H", PWDA = "H" 5.6 8.4 mA AD PWAD = "H", PWDA = "L" 5.6 8.4 mA PWAD = "L", PWDA = "H" DA 10 50 uA PWAD = "L", PWDA = "L" Power down (Note 6) Power Consumption 25 37.5 mW AD+DA PWAD = "H", PWDA = "H" 14 21 mW AD PWAD = "H", PWDA = "L" 14 21 mW PWAD = "L", PWDA = "H" DA 25 125 uW Power down (Note 6) PWAD = "L", PWDA = "L" Notes: 2. The offset of ADC is removed by internal HPF. 3. Input /Output of ADC and DAC scales with VDD voltage. 0.6 X VDD(typ). 4. PSR is applied to VDD with 1kHz, 50mV. 5. Measured by AD725C (SHIBASOKU). RMS mode. 6. In case of power-down mode, all digital input including clocks pins (MCLK, SCLK, LRCK) are held VDD or VSS. But PWAD and PWDA pins are held VSS. M0068-E-01 -4- 2000/4 ASAHI KASEI [AK4550] FILTER CHARACTERISTICS (Ta=25C; VDD=2.3 3.6V; fs=44.1kHz; DEM0="1", DEM1="0") Parameter Symbol min typ ADC Digital Filter (Decimation LPF): Passband (Note 7) 0.1dB PB 0 20.0 -1.0dB 21.1 -3.0dB Stopband SB 27.0 Passband Ripple PR Stopband Attenuation SA 65 Group Delay (Note 8) GD 17.0 Group Delay Distortion GD ADC Digital Filter (HPF): Frequency Response (Note 7) -3dB FR 3.4 -0.5dB 10 -0.1dB 22 DAC Digital Filter: Passband (Note 7) 0.1dB PB 0 22.05 -6.0dB Stopband SB 24.1 Passband Ripple PR Stopband Attenuation SA 43 Group Delay (Note 8) GD 14.8 DAC Digital Filter + Analog Filter FR Frequency Response 0 20.0kHz 0.5 max 17.4 Units kHz kHz kHz kHz dB dB 1/fs us Hz Hz Hz 0.1 0 20.0 0.06 kHz kHz kHz dB dB 1/fs dB Notes: 7. The passband and stopband frequencies scale with fs (sampling frequency). For examples, PB=20.0kHz(@ADC: -1.0dB, DAC: -0.1dB) are 0.454 x fs. 8. The calculating delay time which occurred by digital filtering. This time is from the input of analog signal to setting the 16bit data of both channels to the output register for ADC. For DAC, this time is from setting the 16bit data of both channels on input register to the output of analog signal. DC CHARACTERISTICS (Ta=25C; VDD=2.3 3.6V) Parameter High-Level Input Voltage Low-Level Input Voltage High-Level Output Voltage (Iout=-20uA) Low-Level Output Voltage (Iout=20uA) Input Leakage Current Symbol VIH VIL VOH VOL Iin min 70%VDD VDD-0.1 typ max 30%VDD 0.1 10 Units V V V V uA M0068-E-01 -5- 2000/4 ASAHI KASEI [AK4550] SWITCHING CHARACTERISTICS (Ta=25C; VDD=2.3 3.6V; CL=20pF) Parameter Symbol min typ fCLK 2.048 11.2896 Master Clock Timing 256fs: tCLKL 28 Pulse Width Low tCLKH 28 Pulse Width High fCLK 3.072 16.9344 384fs: tCLKL 23 Pulse Width Low tCLKH 23 Pulse Width High fCLK 4.096 22.5792 512fs: tCLKL 16 Pulse Width Low tCLKH 16 Pulse Width High fs 8 44.1 LRCK Frequency Duty Cycle 45 Serial Interface Timing SCLK Period tSCK 312.5 SCLK Pulse Width Low tSCKL 130 Pulse Width High tSCKH 130 tLRS 50 LRCK Edge to SCLK "" (Note 9) tSLR 50 SCLK "" to LRCK Edge (Note 9) tDLR LRCK Edge to SDTO (MSB) tDSS SCLK "" to SDTO tSDH 50 SDTI Hold Time tSDS 50 SDTI Setup Time Reset Timing PWAD or PWDA Pulse Width tPW 150 (Note 10) tPWV 2081 PWAD "" to SDTO Valid Notes: 9. SCLK rising edge must not occur at the same time as LRCK edge. 10. These cycles are the number of LRCK rising from PWAD rising. max 12.8 19.2 25.6 50 55 Units MHz ns ns MHz ns ns MHz ns ns kHz % ns ns ns ns ns ns ns ns ns ns 1/fs 80 80 M0068-E-01 -6- 2000/4 ASAHI KASEI [AK4550] n Timing Diagram LRCK 50% VDD tSLR tLRS tSCKH tSCKL 50% VDD tDLR tDSS 50% VDD tSDS tSDH 50% VDD SCLK SDTO SDTI Serial Interface Timing tPW 50%VDD tPW PWAD tPWV 50%VDD PWDA SDTO Reset & Initialize Timing M0068-E-01 -7- 2000/4 ASAHI KASEI [AK4550] OPERATION OVERVIEW n System Clock Input The AK4550 can be input MCLK=256fs, 384fs or 512fs. The input clock applied to the MCLK as internal master clock is divided into 256fs automatically. The relationship between the external clock applied to the MCLK input and the desired sample rate is defined in Table 1. The LRCK clock input must be synchronized with MCLK, however the phase is not critical. *fs is sampling frequency. When the synchronization is out of phase by changing the clock frequencies during normal operation, the AK4550 may occur click noise. In case of DAC, click noise is avoided by setting the inputs to "0". All external clocks(MCLK, SCLK, LRCK) must be present unless PWAD and PWDA = "L". If these clocks are not provided, the AK4550 may draw excess current and may not possibly operate properly because the device utilizes dynamic refreshed logic internally. fs 32.0kHz 44.1kHz 48.0kHz 256fs 8.1920MHz 11.2896MHz 12.2880MHz MCLK 384fs 12.2880MHz 16.9344MHz 18.4320MHz 512fs 16.3840MHz 22.5792MHz 24.5760MHz SCLK 32fs 64fs 1.0240MHz 2.048MHz 1.4112MHz 2.822MHz 1.5360MHz 3.072MHz Table 1. System Clock Example n Audio Serial Interface Format Data is shifted in/out the SDTI/SDTO pins using SCLK and LRCK inputs. The data is MSB first, 2's compliment. LRCK 0 1 10 11 12 13 14 15 0 1 10 11 12 13 14 15 0 1 SCLK(i) (32fs) SDTI(i) SDTO(o) 0 15 1 14 6 14 5 15 4 16 3 17 2 1 31 0 0 15 14 1 6 14 5 15 4 16 3 17 2 1 31 0 15 0 14 1 SCLK(i) (64fs) SDTO(o) SDTI(i) 15 14 2 1 0 15 14 2 1 0 15 14 Don't care 15:MSB, 0:LSB 15 14 0 Don't care 15 14 0 Lch Data Figure 1. Audio Interface Timing Rch Data M0068-E-01 -8- 2000/4 ASAHI KASEI [AK4550] n De-emphasis filter The DAC of AK4550 includes the digital de-emphasis filter (tc=50/15us) by IIR filter. This filter corresponds to three frequencies (32kHz, 44.1kHz, 48kHz). The de-emphasis filter selected by DEM0 and DEM1 is enabled for input audio data. The de-emphasis is also disabled at DEM0="1" and DEM1="0". DEM1 DEM0 Mode 0 0 44.1kHz 0 1 OFF 1 0 48kHz 1 1 32kHz Table 2. De-emphasis filter control n Digital High Pass Filter The AK4550 has a Digital High Pass Filter (HPF) for DC-offset cancel. The cut-off frequency of the HPF is 3.4Hz at fs=44.1kHz and the frequency response at 20Hz is -0.12dB. It also scales with the sampling frequency (fs). M0068-E-01 -9- 2000/4 ASAHI KASEI [AK4550] n Power-down & Reset The ADC and DAC of AK4550 are placed in the power-down mode by bringing each power down pin, PWAD , PWDA = "L" independently and each digital filter is also reset at the same time. These resets should always be done after power-up. In case of the ADC, an anlog initialization cycle starts after exiting the power-down mode. Therefore, the output data, SDTO becomes available after 2081 cycles of LRCK clock. This initialization cycle does not affect the DAC operation. Figure 2 shows the power-up sequence when the ADC is powered up before the DAC power-up. PWAD 2081/fs ADC Internal State PWDA DAC Internal State Normal Operation Power-down Init Cycle Normal Operation Normal Operation GD Power-down Normal Operation GD ADC In (Analog) ADC Out (Digital) DAC In (Digital) GD Idle Noise "0"data Idle Noise "0"data GD DAC Out (Analog) Clock In MCLK,LRCK,SCLK The clocks may be stopped. External Mute Mute ON Figure 2. Power-up Sequence M0068-E-01 - 10 - 2000/4 ASAHI KASEI [AK4550] SYSTEM DESIGN Figure 3 shows the system connection diagram. An evaluation board[AKD4550] is available which demonstrates application circuit, optimum layout, power supply arrangements and measurement results. + 4.7u 470 0.1u Rch In + 2.2n 1 470 VCOM AINR AINL VSS VDD DEM0 DEM1 SDTO AOUTR 16 AOUTL 15 Lch In + 2.2n 2 3 4 0.1u Analog Supply 2.3 3.6V AK4550 Top View PWDA PWAD 14 13 Reset Reset 10u + 5 6 7 8 SCLK 12 MCLK 11 LRCK 10 SDTI 9 Controller Mode Control Analog Ground System Ground Figure 3. System Connection Diagram Example Notes: - LRCK=fs, 32fs SCLK 96fs, MCLK=256fs/384fs/512fs. - When AOUT drives some capacitive load, some resistor should be added in series between AOUT and capacitive load. - Electrolytic capacitor value of VCOM depends on low frequency noise of supply voltage. M0068-E-01 - 11 - 2000/4 ASAHI KASEI [AK4550] 1. Grounding and Power Supply Decoupling VDD and VSS are supplied from analog supply and should be separated from system digital supply. Decoupling capacitors should be as near to the AK4550 as possible, with the small value ceramic capacitor being nearest. 2. Voltage Reference The input to VDD voltage sets the analog input/output range. A 0.1uF ceramic capacitor and a 10uF electrolytic capacitor is connected to VDD and VSS pins, normally. VCOM is a signal ground of this chip. An electrolytic less than 4.7uF in parallel with a 0.1uF ceramic capacitor attached to these pins eliminates the effects of high frequency noise. No load current may be drawn from VCOM pin. All signals, especially clock, should be kept away from the VDD, VCOM pins in order to avoid unwanted coupling into the AK4550. 3. Analog Inputs ADC inputs are single-ended and internally biased to VCOM. The input signal range scales with the supply voltage and nominally 0.6xVDD Vpp(typ). The ADC output data format 2's compliment. The output code is 7FFFH(@16bit) for input above a positive full scale and 8000H(@16bit) for input below a negative full scale. The ideal code is 0000H(@16bit) with no input signal. The AK4550 samples the analog inputs at 64fs. The digital filter rejects noise above the stop band except for multiples of 64fs. A simple RC filter (fc=150kHz) may be used to attenuate any noise around 64fs and most audio signals do not have significant energy at 64fs. 4. Analog Outputs The analog outputs are also single-ended and centered around the VCOM voltage. The input signal range scales with the supply voltage and nominally 0.6xVDD Vpp(typ). The DAC input data format is 2's compliment. The output voltage is a positive full scale for 7FFFH(@16bit) and a negative full scale for 8000H(@16bit). The ideal output is VCOM voltage for 0000H(@16bit). If the noise generated by the delta-sigma modulator beyond the audio band would be the problem, the attenuation by external filter is required. DC offsets on analog outputs are eliminated by AC coupling since DAC outputs have DC offsets of a few mV. M0068-E-01 - 12 - 2000/4 ASAHI KASEI [AK4550] n Layout Pattern Example AK4550 requires careful attention to power supply and grounding arrangements to optimize performance. (Please refer to AKD4550 Evaluation Board layout pattern.) 1. VDD pin should be supplied from analog power supply on system, and VSS pin should be connected to analog ground on system. The AK4550 is placed on the analog ground plane, and near the analog ground and digital ground split. And analog and digital ground planes should be only connected at one point. The connection point should be near to the AK4550. VDD pin should be distributed from the point with low impedance of regulator etc. The series resistors are prevent on the clock lines to reduce overshoot and undershoot. To avoid digital noise coupling to analog circuit in the AK4550, a 10pF ceramic capacitor on MCLK pin is connected with digital ground. 0.1uF ceramic capacitors of VDD-VSS pins and VCOM-VSS pins should be located as close to the AK4550 as possible. And these lines should be the shortest connection to pins. 2. 3. 4. 4.7u + 0.1u Rch In + 470 2.2n 1 VCOM Lch In + 470 2.2n AOUTR 16 AOUTL 15 2 AINR 3 AINL 4 VSS Analog Supply 2.3 3.6V AK4550 PWDA 14 PWAD 13 Reset &Power-down 51 51 10P 51 + 10u 0.1u 5 VDD 6 DEM0 7 DEM1 8 SDTO Top View SCLK 12 MCLK 11 LRCK 10 SDTI 9 Controller Analog Ground 51 Digital Ground Mode Control 51 Figure 4. Layout Pattern Example M0068-E-01 - 13 - 2000/4 ASAHI KASEI [AK4550] PACKAGE 16pin TSSOP (Unit: mm) *5.0 1.10max 16 9 A 6.40.2 0.170.05 0.10.1 Detail A 0.50.2 1.0 0.10 0-10 Epoxy Cu Solder plate 2000/4 - 14 - 1 0.220.1 8 0.65 Seating Plane NOTE: Dimension "*" does not include mold flash. n Package & Lead frame material Package molding compound: Lead frame material: Lead frame surface treatment: M0068-E-01 *4.4 ASAHI KASEI [AK4550] MARKING AKM 4550VT XXYYY 1) 2) 3) 4) Pin #1 indication Date Code : XXYYY (5 digits) XX: lot# YYY: Date Code Marketing Code : 4550VT Asahi Kasei Logo IMPORTANT NOTICE * These products and their specifications are subject to change without notice. Before considering any use or application, consult the Asahi Kasei Microsystems Co., Ltd. (AKM) sales office or authorized distributor concerning their current status. * AKM assumes no liability for infringement of any patent, intellectual property, or other right in the application or use of any information contained herein. * Any export of these products, or devices or systems containing them, may require an export license or other official approval under the law and regulations of the country of export pertaining to customs and tariffs, currency exchange, or strategic materials. * AKM products are neither intended nor authorized for use as critical components in any safety, life support, or other hazard related device or system, and AKM assumes no responsibility relating to any such use, except with the express written consent of the Representative Director of AKM. As used here: a. A hazard related device or system is one designed or intended for life support or maintenance of safety or for applications in medicine, aerospace, nuclear energy, or other fields, in which its failure to function or perform may reasonably be expected to result in loss of life or in significant injury or damage to person or property. b. A critical component is one whose failure to function or perform may reasonably be expected to result, whether directly or indirectly, in the loss of the safety or effectiveness of the device or system containing it, and which must therefore meet very high standards of performance and reliability. * It is the responsibility of the buyer or distributor of an AKM product who distributes, disposes of, or otherwise places the product with a third party to notify that party in advance of the above content and conditions, and the buyer or distributor agrees to assume any and all responsibility and liability for and hold AKM harmless from any and all claims arising from the use of said product in the absence of such notification. M0068-E-01 - 15 - 2000/4 |
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