ASAHI KASEI [AK4551] AK4551 Low Power & Small Package 20bit ∆Σ CODEC GENERAL DESCRIPTION The AK4551 is a low voltage 20bit A/D & D/A converter for portable digital audio system. In the AK4551, 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 AK4551 are single-ended, therefore, any external filters are not required. The AK4551 is suitable for portable digital audio system, as the AK4551 is lower power dissipation and a smaller package than AK4519. 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 (AK4519 compatible) - ADC: 20bit MSB justified - DAC: 20bit 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: 2.2 to 3.6V o Low Power Supply Current: 10mA o Ta = -20 to 85°C o Very Small Package: 16pin TSSOP VDD AINL AINR VCOM VSS ∆Σ Modulator Decimation Filter ∆Σ Modulator Decimation Filter Clock Divider MCLK LRCK SCLK Serial I/O Interface Common Voltage SDTO SDTI DEM0 AOUTL AOUTR LPF ∆Σ Modulator LPF ∆Σ Modulator MS0029-E-00 8X DEM1 Interpolator 8X PWDA Interpolator PWAD 2000/5 -1- ASAHI KASEI [AK4551] n Ordering Guide -20 ∼ +85°C 16pin TSSOP (0.65mm pitch) Evaluation Board for AK4551 AK4551VT AKD4551 n Pin Layout VCOM 1 16 AOUTR AINR 2 15 AOUTL AINL 3 14 PWDA VSS 4 13 PWAD VDD 5 12 SCLK DEM0 6 11 MCLK DEM1 7 10 LRCK SDTO 8 9 SDTI Top View PIN/FUNCTION No. Pin Name I/O Function 1 2 3 4 5 6 7 8 9 10 11 12 VCOM AINR AINL VSS VDD DEM0 DEM1 SDTO SDTI LRCK MCLK SCLK O I I I I O I I I I 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 13 PWAD I 14 PWDA I 15 16 AOUTL AOUTR O O MS0029-E-00 2000/5 -2- ASAHI KASEI [AK4551] ABSOLUTE MAXIMUM RATINGS (VSS=0V; Note 1) Parameter Symbol VDD IIN VIN Ta Tstg Power Supply Input Current (Any Pin Except Supplies) Input Voltage Ambient Temperature (power applied) Storage Temperature min -0.3 -0.3 -20 -65 max 4.6 ±10 VDD+0.3 85 150 Units V mA V °C °C Note 1. All voltages with respect to ground. 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 2.2 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. MS0029-E-00 2000/5 -3- ASAHI KASEI [AK4551] ANALOG CHARACTERISTICS (Ta=25°C; 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=470Ω (Note 2) Resolution 20 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 kΩ Power Supply Rejection (Note 4) 35 dB DAC Analog Output Characteristics: Resolution 20 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 kΩ Load Capacitance 30 pF Power Supply Rejection (Note 4) 50 dB Power Supplies Power Supply Current AD+DA AD DA Power down (Note 5) Power Consumption PWAD = “H”, PWDA = “H” PWAD = “H”, PWDA = “L” PWAD = “L”, PWDA = “H” PWAD = “L”, PWDA = “L” 10 5.6 5.6 10 15 8.4 8.4 50 mA mA mA uA mW 37.5 25 PWAD = “H”, PWDA = “H” AD+DA mW 21 14 AD PWAD = “H”, PWDA = “L” mW 21 14 DA PWAD = “L”, PWDA = “H” uW 125 25 PWAD = “L”, PWDA = “L” Power down (Note 5) Note 2. The offset of ADC is removed by internal HPF. Note 3. Input /Output of ADC and DAC scales with VDD voltage. 0.6 X VDD (typ). Note 4. PSR is applied to VDD with 1kHz, 50mV. Note 5. In case of power-down mode, all digital input including clocks pins (MCLK, SCLK and LRCK) are held VDD or VSS. But PWAD and PWDA pins are held VSS. MS0029-E-00 2000/5 -4- ASAHI KASEI [AK4551] FILTER CHARACTERISTICS (Ta=25°C; VDD=2.2 ∼ 3.6V; fs=44.1kHz; DEM0=“1”, DEM1=“0”) Parameter Symbol min typ max Units ADC Digital Filter (Decimation LPF): 17.4 kHz PB 0 Passband (Note 6) ±0.1dB kHz 20.0 -1.0dB kHz 21.1 -3.0dB Stopband SB 27.0 kHz Passband Ripple PR dB ±0.1 Stopband Attenuation SA 65 dB Group Delay (Note 7) GD 17.0 1/fs Group Delay Distortion 0 us ∆GD ADC Digital Filter (HPF): Hz FR 3.4 Frequency Response (Note 6) -3dB Hz 10 -0.5dB Hz 22 -0.1dB DAC Digital Filter: PB 0 20.0 kHz Passband (Note 6) ±0.1dB 22.05 kHz -6.0dB Stopband SB 24.1 kHz Passband Ripple PR dB ±0.06 Stopband Attenuation SA 43 dB Group Delay (Note 7) GD 15.4 1/fs Group Delay Distortion 0 us ∆GD DAC Digital Filter + Analog Filter FR dB Frequency Response 0 ∼ 20.0kHz ±0.5 Note 6. 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. Note 7. The calculating delay time which occurred by digital filtering. This time is from the input of analog signal to setting the 20bit data of both channels to the output register for ADC. For DAC, this time is from setting the 20bit data of both channels on input register to the output of analog signal. DC CHARACTERISTICS (Ta=25°C; VDD=2.2 ∼ 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 MS0029-E-00 min 70%VDD VDD-0.1 - typ - max 30%VDD 0.1 ± 10 Units V V V V uA 2000/5 -5- ASAHI KASEI [AK4551] SWITCHING CHARACTERISTICS (Ta=25°C; VDD=2.2 ∼ 3.6V; CL=20pF) Parameter Symbol min 2.048 fCLK Master Clock Timing 256fs: 28 tCLKL Pulse Width Low 28 tCLKH Pulse Width High 3.072 fCLK 384fs: 23 tCLKL Pulse Width Low 23 tCLKH Pulse Width High 4.096 fCLK 512fs: 16 tCLKL Pulse Width Low 16 tCLKH Pulse Width High fs 8 LRCK Frequency Duty Cycle 45 Serial Interface Timing SCLK Period 312.5 tSCK SCLK Pulse Width Low 130 tSCKL Pulse Width High 130 tSCKH 50 tLRS LRCK Edge to SCLK “↑” (Note 8) 50 tSLR SCLK “↑” to LRCK Edge (Note 8) tDLR LRCK Edge to SDTO (MSB) tDSS SCLK “↓” to SDTO 50 tSDH SDTI Hold Time 50 tSDS SDTI Setup Time Reset Timing PWAD or PWDA Pulse Width tPW 150 (Note 9) PWAD “↑” to SDTO Valid tPWV Note 8. SCLK rising edge must not occur at the same time as LRCK edge. typ 11.2896 max 12.8 16.9344 19.2 22.5792 25.6 44.1 50 55 80 80 2081 Units MHz ns ns MHz ns ns MHz ns ns kHz % ns ns ns ns ns ns ns ns ns ns 1/fs Note 9. These cycles are the number of LRCK rising from PWAD rising. MS0029-E-00 2000/5 -6- ASAHI KASEI [AK4551] n Timing Diagram 50% VDD LRCK tSLR tLRS tSCKH tSCKL 50% VDD SCLK tDLR tDSS 50% VDD SDTO tSDS tSDH 50% VDD SDTI Serial Interface Timing tPW 50%VDD PWDA tPW 50%VDD PWAD tPWV SDTO Reset & Initialize Timing MS0029-E-00 2000/5 -7- ASAHI KASEI [AK4551] OPERATION OVERVIEW n System Clock Input The AK4551 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 AK4551 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 AK4551 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 SCLK 32fs 64fs 1.0240MHz 2.048MHz 1.4112MHz 2.822MHz 1.5360MHz 3.072MHz 512fs 16.3840MHz 22.5792MHz 24.5760MHz 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 SCLK(i) (64fs) 0 SDTO(o) SDTI(i) 1 2 19 18 12 8 Don’t care 13 7 14 6 19 18 20 21 31 0 2 19 18 0 12 11 1 1 0 12 8 Don’t care 13 7 14 6 19 18 20 21 31 0 19 0 12 11 1 1 0 19:MSB, 0:LSB Lch Data Rch Data Figure 1. Audio Interface Timing MS0029-E-00 2000/5 -8- ASAHI KASEI [AK4551] n De-emphasis filter The DAC of AK4551 includes the digital de-emphasis filter (tc=50/15us) by IIR filter. This filter corresponds to three frequencies (32kHz, 44.1kHz and 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 AK4551 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). MS0029-E-00 2000/5 -9- ASAHI KASEI [AK4551] n Power-down & Reset The ADC and DAC of AK4551 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 Normal Operation Power-down Init Cycle Normal Operation PWDA DAC Internal State Normal Operation Normal Operation Power-down GD GD ADC In (Analog) ADC Out (Digital) “0”data Idle Noise DAC In (Digital) Idle Noise “0”data GD GD DAC Out (Analog) Clock In MCLK,LRCK,SCLK The clocks may be stopped. External Mute Mute ON Figure 2. Power-up Sequence MS0029-E-00 2000/5 - 10 - ASAHI KASEI [AK4551] SYSTEM DESIGN Figure 3 shows the system connection diagram. An evaluation board [AKD4551] is available which demonstrates application circuit, optimum layout, power supply arrangements and measurement results. 4.7u + 0.1u 470 Rch In + 2.2n 470 Lch In + 2.2n Analog Supply 2.2 ∼ 3.6V Mode Control 10u + 1 VCOM AOUTR 16 2 AINR AOUTL 15 3 AINL 4 VSS 0.1u AK4551 Top View PWDA 14 Reset PWAD 13 Reset SCLK 12 5 VDD 6 DEM0 MCLK 11 7 DEM1 LRCK 10 8 SDTO SDTI Controller 9 Analog Ground System Ground Figure 3. System Connection Diagram Example Notes: - LRCK=fs, 40fs ≤ 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. MS0029-E-00 2000/5 - 11 - ASAHI KASEI [AK4551] 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 AK4551 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 AK4551. 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 7FFFFH(@20bit) for input above a positive full scale and 80000H(@20bit) for input below a negative full scale. The ideal code is 00000H (@20bit) with no input signal. The AK4551 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 7FFFFH(@20bit) and a negative full scale for 80000H(@20bit). The ideal output is VCOM voltage for 00000H(@20bit). 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. MS0029-E-00 2000/5 - 12 - ASAHI KASEI [AK4551] n Layout Pattern Example AK4551 requires careful attention to power supply and grounding arrangements to optimize performance. (Please refer to AKD4551 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 AK4551 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 AK4551. 2. VDD pin should be distributed from the point with low impedance of regulator etc. 3. The series resistors are prevent on the clock lines to reduce overshoot and undershoot. To avoid digital noise coupling to analog circuit in the AK4551, a 10pF ceramic capacitor on MCLK pin is connected with digital ground. 4. 0.1uF ceramic capacitors of VDD-VSS pins and VCOM-VSS pins should be located as close to the AK4551 as possible. And these lines should be the shortest connection to pins. + 4.7u Rch In + 0.1u 470 2.2n Lch In + 470 2.2n Analog Supply 2.2 ∼ 3.6V 1 VCOM AOUTR 16 2 AINR AOUTL 15 3 AINL AK4551 4 VSS + 10u 0.1u PWDA 14 Reset &Power-down PWAD 13 Top View 5 VDD 51 SCLK 12 6 DEM0 MCLK 11 7 DEM1 LRCK 10 8 SDTO SDTI 9 51 10P 51 Analog Ground Digital Ground Controller 51 51 Mode Control Figure 4. Layout Pattern Example MS0029-E-00 2000/5 - 13 - ASAHI KASEI [AK4551] PACKAGE 16pin TSSOP (Unit: mm) *5.0 16 1.10max 9 *4.4 6.4±0.2 A 1 0.22±0.1 8 0.65 0.17±0.05 0.1±0.1 0.5±0.2 Detail A Seating Plane 1.0 0.10 NOTE: Dimension "*" does not include mold flash. 0-10° n Package & Lead frame material Package molding compound: Lead frame material: Lead frame surface treatment: Epoxy Cu Solder plate MS0029-E-00 2000/5 - 14 - ASAHI KASEI [AK4551] MARKING AKM 4551VT XXYYY 1) 2) 3) 4) Pin #1 indication Date Code : XXYYY (5 digits) XX: lot# YYY: Date Code Marketing Code : 4551VT 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. MS0029-E-00 2000/5 - 15 -