ASAHI KASEI [AK5351] AK5351 Enhanced Dual bit ∆Σ 20bit ADC GENERAL DESCRIPTION The AK5351 is a 20-bit, 64x oversampling rate(64fs), 2-channel A/D converter for stereo digital systems. The ∆Σ modulator in the AK5351 uses the new developed Enhanced Dual bit architecture. This new architecture achieves the wider dynamic range, while keeping much the same superior distortion characteristics as the conventional Single bit way. The AK5351 is suitable for digital surround and Hi-Fi audio application such as Car-audio, MD, etc. Analog inputs of the AK5351 are normally Full-differential inputs, while they are also acceptable Single-ended inputs. The AK5351 is available in a small 24pin VSOP package which will reduce your system space. FEATURES Full-differential / Single-ended inputs S/(N+D): 97dB DR, S/N: 103dB Linear phase digital filter Pass band: 0~22kHz(@fs=48kHz) Pass band ripple: ±0.005dB Stop band attenuation: 80dB Digital HPF for DC-offset cancel Master clock: 256fs/384fs Power supply: 5V±10% Small package: 24pinVSOP 0166-E-00 1997/4 -1- ASAHI KASEI [AK5351] Ordering Guide AK5351-VF -40~85°C AKD5351/2 Evaluation Board 24pin VSOP Pin Layout Replacement from AK5350 to AK5351 Package Analog Inputs Voltage fc of HPF(@fs=48kHz) SCLK AK5350 28VSOP AK5351 24VSOP *)Interchangeable with AK5350 ±2.10Vp-p *)Acceptable Single-ended 1Hz ~128fs ±3.47Vp-p 7Hz ~64fs 0166-E-00 1997/4 -2- ASAHI KASEI [AK5351] PIN/FUNCTION No. Pin Name I/O 1 2 3 AINR+ AINRVREF I I O 4 5 6 7 8 10 11 14 9 VA AGND AINL+ AINLTST1 TST2 TST3 TST4 HPFE I I 12 13 16 VD DGND PD I 17 MCLK I 18 SCLK I/O 19 LRCK I/O 20 FSYNC I/O I FUNCTION Right channel analog positive input pin Right channel analog negative input pin Voltage Reference output pin (VA-2.6V) Normally connected to VA with a 0.1uF ceramic capacitor in parallel with a 10uF electrolytic capacitor. Analog section Analog Power Supply, +5V Analog section Analog Ground Left channel analog positive input pin Left channel analog negative input pin Test pin (Pull-down pin) Should be left floating. High Pass Filter Enable pin (Pull-up pin) "H": ON "L": OFF Digital section Digital Power Supply pin, +5V Digital section Digital Ground pin Power Down pin "L" brings the device into power-down mode. Must be done once after power-on. Master Clock input pin CMODE="H":384fs CMODE="L":256fs Serial Data Clock pin Data is clocked out at the falling edge of SCLK. Slave mode: 64fs clock is input usually. Master mode: SCLK outputs a 64fs clock. SCLK stays low during the power-down mode(PD="L"). L/R Channel Clock Select pin Slave mode: An fs clock is fed to this LRCK pin. Master mode: LRCK output an fs clock. LRCK goes "H" at SMODE2="L" and "L" at SMODE2="H" during reset when SMODE1 "H". Frame Synchronization Signal pin Slave mode: When "H", data bits are clocked out on SDATA. 2 As I S slave mode ignores FSYNC, it should hold "L" or "H". Master mode: FSYNC outputs 2fs clock. Stay low during the power-down mode(PD="L"). 0166-E-00 1997/4 -3- ASAHI KASEI [AK5351] 21 SDATA O 22 CMODE I 23 15 SMODE1 SMODE2 I I 24 VB - Serial Data Output pin Data are output with MSB first, in 2's complement format. After 20 bits are output it turns to "L". It also remains "L" at a power-down mode(PD="L"). Master Clock Selection pin "L": MCLK=256fs "H": MCLK=384fs Serial Interface Mode Select pin Defines the directions of LRCK, SCLK and FSYNC pins and Output Data Format. SMODE2 is pull-down pin. SMODE1 SMODE2 MODE LRCK L L Slave mode: MSB justified : H/L 2 : H/L H L Master mode: Similar to I S 2 L H Slave mode: I S : L/H 2 : L/H H H Master mode: I S Substrate Power Supply, +5V 0166-E-00 1997/4 -4- ASAHI KASEI [AK5351] ABSOLUTE MAXIMUM RATINGS (AGND,DGND=0V; Note 1 ) Parameter DC Power Supply:Analog Power(VA pin) Digital Power(VD pin) (Note 2 ) Substrate Power(VB pin) Input Current (Any pin except supplies) Analog Input Voltage AINL+,AINL-,AINR+,AINR-pins (Note 2 ) Digital Input Voltage (Note 2 ) Ambient Temperature Storage Temperature Symbol min max Units VA VD VB IIN VINA -0.3 -0.3 -0.3 -0.3 6.0 6.0/VB+0.3 6.0 ±10 6.0/VA+0.3 V V mA V VIND Ta Tstg -0.3 -40 -65 6.0/VB+0.3 85 150 V °C °C Note 1 : All voltage with respect to ground. Note 2 : Absolute maximum value is the highest voltage in 6.0V, VA+0.3V and VB+0.3V. WARNING: Operation beyond these limits may result in permanent damage to the device. Normal operation is not guaranteed at these extremes. RECOMMENDED OPERATING CONDITIONS (AGND,DGND=0V; Note 1 ) Parameter DC Power Supplies: Analog Power Digital Power(VD pin) (VB pin) (Note 3 ) Symbol min typ max Units VA VD VB 4.50 4.50 4.50 5.0 5.0 5.0 5.50 VB 5.50 V V V Note 1 : All voltages with respect to ground. Note 3 : The VA and VB are connected together through the chip substrate and have several ohms resistance. The VA and VB should be powered at the same time or earlier than VD. * AKM assumes no responsibility for the usage beyond the conditions in this data sheet. 0166-E-00 1997/4 -5- ASAHI KASEI [AK5351] ANALOG CHARACTERISTICS (Ta=25°C; VA,VD,VB=5.0V; fs=48kHz; 20bit; Input signal frequency=1kHz, Measurement Bandwidth=10Hz~20kHz; unless otherwise specified.) Parameter min Resolution Analog Input Characteristics (Analog source impedance: 330Ω) S/(N+D) (Note 4 ) Dynamic Range (A-weighted) (Note 5 ) S/N (A-weighted) (Note 6 ) Interchannel Isolation (f=1kHz) Interchannel Gain Mismatch Gain drift Input Voltage Range Input Impedance 88 97 97 100 ±1.97 30 typ max Units 20 Bits 97 103 103 120 0.1 ±200 ±2.10 50 dB dB dB dB dB ppm/°C 0.3 ±2.23 Vp-p kΩ 25 9 mA mA Power Supplies Power Supply Current (Note 7 ) Normal Operation (PD="H") VA+VB VD Power-Down mode (PD="L") VA+VB VD Power Consumption (Note 7 ) Normal Operation Power-Down mode Power Supply Rejection Ratio 15 6 uA uA 20 10 105 150 50 170 mW uW dB Note 4 : The ratio of the rms value of the signal to the sum of all other spectral components up to 20kHz except for the signal (included harmonic component, excluded DC component, analog input signal is -0.5dB). Inversed of THD+N. Note 5 : S/(N+D) with an input signal of 60dB below full-scale. Note 6 : When using only 20kHzLPF, S/N and DR are 99dB(typ.). When using CCIR-ARM filter, S/N is 99dB(typ.) Note 7 : Almost no current is supplied from VB pin. 0166-E-00 1997/4 -6- ASAHI KASEI [AK5351] DIGITAL FILTER CHARACTERISTICS (Ta=25°C; VA,VD,VB=5.0V±10%; fs=48kHz) Low Pass Filter characteristics Passband -0.005dB -0.02dB -0.06dB (Note 8 ) Stopband (Note 9 ) Passband Ripple (Note 10 ) Stopband Attenuation (Note 9 ,Note 11 ) Group Delay Distortion Group Delay (Note 12 ) Symbol min PB 0 SB PR SR ∆ GD 26.5 typ max Units 21.5 21.768 22.0 kHz GD 29.3 kHz dB dB us 1/fs FR 1.0 2.9 6.5 Hz Hz Hz ±0.005 80 0 High Pass Filter characteristics Frequency Response -3dB(Note 8 ) -0.5dB -0.1dB Note 8 : Note 9 : Note 10 : Note 11 : These frequencies scale with the sampling frequency(fs). Stopband is 26.5kHz to 3.0455MHz at fs=48kHz. Passband is DC to 21.5kHz at fs=48kHz. The analog modulator samples the input at 3.072MHz for a system sampling rate of fs=48kHz. These is no rejection of input signals at those bandwidths which are multiples of the sampling frequency (n x 3.072MHz ±22kHz ;n=0,1,2,3…). Note 12 : The calculation delay time occurred by digital filtering. This is the time from the input of analog signal to setting the 20bit data of both channels to the output registers. GD=29.3/fs. ELECTRICAL CHARACTERISTICS Digital Characteristics (Ta=25°C; VA,VD,VB=5.0V±10%) Parameter High-Level Input voltage Low-Level Input voltage High-Level Output voltage Low-Level Output voltage Input Leakage Current Iout=-20uA Iout=20uA (Note 13 ) Symbol min typ max Units VIH VIL VOH VOL Iin 70%VD VD-0.1 - - 30%VD 0.1 ±10 V V V V uA Note 13 : Except for pull-down and pull-up pins. TST1, TST2, TST3, TST4, SMODE2 pins have internal pull-down device, HPFE pin has internal pull-up devive(Typ. 50kΩ) 0166-E-00 1997/4 -7- ASAHI KASEI [AK5351] SWITCHING CHARACTERISTICS (Ta=25°C; VA,VD,VB=5.0V±10%; CL=20pF) Parameter Control Clock Frequency Master Clock 256fs: Pulse width Low Pulse width High 384fs: Pulse width Low Pulse width High Serial Data Output Clock Channel Select Clock(Sampling Frequency) Duty Cycle Serial Interface Timing (Note 14 ) Slave Mode(SMODE1="L") SCLK Period SCLK Pulse width Low Pulse width High SCLK Rising to LRCK Edge (Note 15 ) LRCK Edge to SCLK Rising (Note 15 ) LRCK Edge to SDATA MSB Valid SCLK Falling to SDATA Valid SCLK Rising to FSYNC Edge(Note 15 ) FSYNC Edge to SCLK Rising(Note 15 ) Master Mode(SMODE1="H") SCLK Frequency Duty Cycle FSYNC Frequency Duty Cycle SCLK Falling to LRCK Edge LRCK Edge to FSYNC Rising SCLK Falling to SDATA Valid SCLK Falling to FSYNC Edge Power down timing PD Pulse width PD Rising to SDATA Valid (Note 16 ) Symbol min typ max Unit fCLK tCLKL tCLKH fCLK tCLKL tCLKH fSLK fs 2.048 30.0 30.0 3.072 20.0 20.0 12.288 13.824 18.432 20.736 3.072 48 6.912 54 75 MHz ns ns MHz ns ns MHz kHz % tSLK tSLKL tSLKH tSHLR tLRSH tDLR tDSS tSHF tFSH 144.7 65 65 30 30 8 25 50 50 30 30 64fs 50 2fs 50 fSLK fFSYNC tSLR tLRF tDSS tSF -20 tPDW tPDV 150 20 1 50 20 -20 516 ns ns ns ns ns ns ns ns ns Hz % Hz % ns tslk ns ns ns 1/fs Note 14 : Refer to Serial Data Interface. Note 15 : Specified LRCK and FSYNC edges not to coincide with the rising edges of SCLK. Note 16 : The number of LRCK rising edges after PD brought high. The value is in master mode. In slave mode it becomes one LRCK clock(1/fs) longer. 0166-E-00 1997/4 -8- ASAHI KASEI [AK5351] Timing Chart 0166-E-00 1997/4 -9- ASAHI KASEI [AK5351] OPERATION OVERVIEW System clock In slave mode, MCLK(256fs/384fs), LRCK(fs) and SCLK(64fs) are required for AK5351. Use a signal divided from the MCLK for LRCK. In master mode, only MCLK is needed. A LRCK clock rate meets standard audio rates (32kHz, 44.1kHz, 48kHz). In slave mode, the MCLK should be synchronized with LRCK but the phase is free of care. The AK5351 includes the phase detect circuit for LRCK clock, the AK5351 is reset automatically when the synchronization is out of phase by changing the clock frequencies. (Please refer to the "Asynchronization reset."). When changing sampling frequency(fs) after power-up, AK5351 should be reset. During the operation (PD="H") following external clocks should never be stopped : CLK in master mode and MCLK, SCLK and LRCK in slave mode. When the clocks stop there is a possibility that the device comes into a malfunction because of over currents in the dynamic logic. If the external clocks are not present, the AK5351 should be in the power-down mode. (PD="L") fs 32.0kHz 44.1kHz 48.0kHz Master Clock (MCLK) SCLK(64fs) 256fs 384fs 8.1920MHz 11.2896MHz 12.2880MHz 12.2880MHz 16.9344MHz 18.4320MHz 2.0480MHz 2.8224MHz 3.0720MHz Table 1 . System Clock Clock Circuit CMODE MCLK L 256fs H 384fs AK5351 has an internal divider as shown in the above figure. The device can interface either or an external MCLK(256fs or 384fs) by controlling CMODE pin. 0166-E-00 1997/4 - 10 - ASAHI KASEI [AK5351] Serial Data Interface Audio Serial Interface has four kinds of mode, it can be changed by SMODE1 and SMODE2 pins. Data format is MSB first, 2's complement. Figure Figure 1 Figure 2 Figure 3 Figure 4 SMODE1 L H L H SMODE2 Mode L Slave Mode: 20bit, MSB justified 2 L Master Mode: Similar to I S 2 H Slave Mode: I S 2 H Master Mode: I S Table 2 . Serial Interface L/R polarity Lch=H, Rch=L Lch=H, Rch=L Lch=L, Rch=H Lch=L, Rch=H 1) SLAVE mode An output channel is defined by LRCK. Both channel data are output in sequence, in order of the Lch first then Rch at the rate of fs. Data bits are clocked out via the SDATA pin at SCLK rate. Figure 1 and Figure 3 shows data output timing at SCLK=64fs. FSYNC enables SCLK to start clocking out data. The MSB is clocked out by 2 the LRCK edge. SCLK causes the ADC to output succeeding bits when FSYNC is high. However, as I S slave mode ignores FSYNC, it should hold "L" or "H". 2) MASTER mode In MASTER mode, the A/D converter is driven from a master clock(MCLK:256fs/384fs) and outputs all other clocks(LRCK, SCLK). The falling edge of SCLK causes the ADC to output each bit. Figure 2 and Figure 4 shows the output timing. 2x fs clock of 50% duty is output via the FSYNC pin. FSYNC rises one SCLK cycle after the transition of LRCK edges and stays high during 16 serial clocks(16*tSLK). Upper 16 bit data is output during FSYNC "H", lower 4 bit is output after FSYNC "L" transition. Figure 1 . Data Output Timing (Slave mode) 0166-E-00 1997/4 - 11 - ASAHI KASEI [AK5351] 0166-E-00 1997/4 - 12 - ASAHI KASEI [AK5351] Power-down mode The AK5351 has to be reset once by bringing PD "L" upon power-up. All internal registers of the digital filter and so on in the AK5351 are reset by this operation. When exiting the power-down mode(PD="H"), the internal timing starts clocking by first MCLK "↑"(rising edge). In master mode internal counter starts at once, in slave mode internal counter starts after synchronizing with the first rising edge of LRCK. The serial output data is available after 516 counting clock of LRCK cycle. Asynchronization-reset In slave mode, if the phase difference between LRCK and internal control signals is larger than +1/16~-1/16 of word period(1/fs), the synchronization of internal control signals with LRCK is done automatically at the first rising edge of LRCK. High Pass Filter(HPFE pin) The AK5351 has a Digital High Pass Filter(HPF) for DC-offset cancel. When HPFE pin goes "H", HPF is enabled. The cut-off frequency of the HPF is 1Hz(@fs=48kHz). It also scales with the sampling frequency(fs). The HPF can be disabled by bringing HPFE pin "L". In this case, the AK5351 has the DC-offset of a few mV. 0166-E-00 1997/4 - 13 - ASAHI KASEI [AK5351] SYSTEM DESIGN Figure 5 shows the system connection diagram. Figure 6 and Figure 7 shows the input buffer circuit. An evaluation board[AKD5351/2] is available which demonstrates the optimum layout, power supply arrangement and measurement results. Figure 5 . System Connection Diagram Example NOTE: +5V Analog should be powered the same time or earlier than +5V Digital. Grounding and Power Supply Decoupling The AK5351 requires careful attention to power supply and grounding arrangements. The VA and VB are connected together through the chip substrate and have several ohm resistance. The power to VB should come up at the same time or faster than the power to VD, when they are fed separately to the device (Figure 5). As to the connections of decoupling capacitors, refer to Figure 5 . The 0.1uF of decoupling capacitors connected power supply pins should be as near as possible to the power supply pin. As AIN± pins is near VD pin, ground pattern should be inserted between VD line and AINL± lines to avoid digital noise coupling. Refer to evaluation board manual of AKD5352/1 Rev.B about board layout. 0166-E-00 1997/4 - 14 - ASAHI KASEI [AK5351] Analog connections Analog signal is differentially input into the modulator via the AIN+ and the AIN- pins. The input voltage is the difference between AIN+ and AIN- pins. The full-scale of each pin is ±2.10Vp-p on its reference voltage(VREF). In case that the positive input is more than its full-scale, the AK5351 outputs positive 7FFFFH(Hex, Full-scale). In case that the negative input is more than its full-scale, the AK5351 outputs negative 80000H(Hex, Full-scale). Analog inputs of the AK5351 are normally Full-differential inputs, while they are also acceptable Single-ended inputs. In case of Single-ended inputs, analog signal is input from either positive or negative input and the other side inputs bias voltage. Figure 7 is a circuit example which analog input signal is input 4.20Vp-p into AIN- pin and bias voltage into AIN+ pin. The DC offset is removed by the internal HPF. AK5351 samples the analog inputs at 3.072MHz with fs=48kHz. The digital filter rejects all noise between 26.5kHz and 3.0455MHz. However, the filter will not reject frequencies right around 3.072MHz ( and multiples of 3.072MHz). Most audio signals do not have significant noise energy at 3.072MHz. Hence, a simple RC filter is sufficient to attenuate any noise energy at 3.072MHz. The reference voltage for A/D converter is supplied from the VREF pin at VA reference. In order to eliminate the effects of high frequency noise on the VREF pin, a 10uF or less electrolytic capacitor and a 0.1uF ceramic capacitor should be connected parallel between the VREF and the VA pins. No current should be driven from the VREF pin. The AK5351 accepts +5V supply voltage. Any voltage which exceeds the upper limit of (VA+)+0.3V and lower limit of AGND-0.3V and any current beyond 10mA for the analog input pins(AINL±, AINR±) should be avoided. Excessive currents to the input pins may damage the device. Hence input pins must be protected from signals at or beyond these limits. Use caution specially in case of using ±15V in surrounding analog circuit. Figure 6 . Full-differential Input Buffer Circuit Example Figure 7 . Single-ended Input Buffer Circuit Example 0166-E-00 1997/4 - 15 - ASAHI KASEI [AK5351] Digital Connections To minimize digital originated noise, connect the ADC digital outputs only to CMOS inputs. Logic families of 4000B, 74HC, 74AC, 74ACT and 74HCT series are suitable. Multiple AK5351 In systems where multiple ADC's are required, care must be taken to insure the internal clocks are synchronized between converters to make simultaneous sampling. In slave mode, synchronous sampling is achieved by supplying the same MCLK and LRCK to all converters. In master mode, the same PD signal is supplied to each ADC. The PD state is released at the first rising edge of MCLK after bringing PD into high. Hence, if the rising edge of PD and rising edge of MCLK coincides together the sampling difference among the ADC's modulator would occur. The difference could be 1/256fs in the sampling clock(64fs) of the modulator, typically 81ns at fs=48kHz. 0166-E-00 1997/4 - 16 - ASAHI KASEI [AK5351] PACKAGE z 24pin VSOP (Unit: mm) Material & Lead finish Package: Lead-frame: Lead-finish: Epoxy Copper Soldering plate 0166-E-00 1997/4 - 17 - ASAHI KASEI [AK5351] MARKING Contents of AAXXXX AA: Lot# XXXX: Date Code 0166-E-00 1997/4 - 18 - IMPORTANT NOTICE zThese 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. zAKM assumes no liability for infringement of any patent, intellectual property, or other right in the application or use of any information contained herein. zAny 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. zAKM 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. zIt 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.