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ASAHI KASEI
[AK4555]
Low Power & Small Package 20bit CODEC
AK4555
GENERAL DESCRIPTION The AK4555 is a low voltage 20bit A/D & D/A converter for portable digital audio system. In the AK4555, 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 AK4555 are single-ended, therefore, any external filters are not required. The AK4555 is suitable for portable digital audio system, as the AK4555 is low power dissipation and a small package. FEATURES HPF for DC-offset cancel (fc=3.4Hz) Single-ended ADC - S/(N+D): 80dB@VDD=2.5V - Dynamic Range, S/N: 89dB@VDD=2.5V 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 Audio I/F format: MSB First, 2's Compliment - ADC, DAC: I2S Input/Output Voltage: 0.6 x VDD (=1.5Vpp@VDD=2.5V) High Jitter Tolerance Sampling Rate: 8kHz to 50kHz Master Clock: 256fs/384fs/512fs/768fs (fs=8kHz to 50kHz) 1024fs (fs=8kHz to 25kHz) Power Supply: 1.6 to 3.6V Low Power Supply Current: 8.6mA Ta = -40 to 85C Very Small Package: 16pin TSSOP
VDD VSS Modulator Modulator Common Voltage Modulator Modulator 8X Interpolator 8X Interpolator PWDAN PWADN Decimation Filter Decimation Filter Serial I/O Interface Clock Divider MCLK LRCK SCLK SDTO SDTI DEM0 AOUTL LPF DEM1
AINL
AINR
VCOM
AOUTR
LPF
MS0363-E-01 -1-
2005/08
ASAHI KASEI
[AK4555]
Ordering Guide
AK4555VT AKD4555 16pin TSSOP (0.65mm pitch) -40 +85C Evaluation Board for AK4555
Pin Layout
VCOM AINR AINL VSS VDD DEM0 DEM1 SDTO
1 2 3 4 5 6 7 8
16 15 14
AOUTR AOUTL PWDAN PWADN SCLK MCLK LRCK SDTI
Top View
13 12 11 10 9
Comparison with AK4550 and AK4554
Item Power Supply Voltage Audio I/F Format VCOM pin ADC S/(N+D) (typ) ADC Input Resistance (typ) Power Supply Current (typ) AD+DA AD DA DAC Digital Filter Stopband Attenuation (min) Passband Ripple (max) Group Delay MCLK External Circuit VCOM pin AINL, AINR pins AK4550 2.3 3.6V ADC: 16bit MSB justified DAC: 16bit LSB justified 0.45 x VDD 82dB 100k 10mA 5.6mA 5.6mA 43dB 0.06dB 14.8/fs 256fs/384fs/512fs AK4554 AK4555 1.6 3.6V ADC: 16bit MSB justified I2S DAC: 16bit LSB justified 0.5 x VDD 80dB 70k 8mA 4mA 4.4mA 54dB 0.02dB 19.0/fs 256fs/384fs/512fs/768fs (fs=850kHz) 1024fs (fs=825kHz) 0.1F RC filter is on-chip.
4.7F + 0.1F RC filter is needed.
MS0363-E-01 -2-
2005/08
ASAHI KASEI
[AK4555]
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 PWADN PWDAN AOUTL AOUTR I/O O I I I I O I I I I I I O O Function Common Voltage Output Pin, 0.5 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
Note: All input pins except analog input pins (AINR and AINL) should not be left floating.
Handling of Unused Pin
The unused I/O pins should be processed appropriately as below. Classification Analog Digital Pin Name AINR, AINL, AOUTL, AOUTR SDTO SDTI Setting These pins should be open. This pin should be open. This pin should be connected to VSS.
MS0363-E-01 -3-
2005/08
ASAHI KASEI
[AK4555]
ABSOLUTE MAXIMUM RATINGS
(VSS=0V; Note 1) Parameter Power Supply Input Current (any pins except for 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 Note 1. All voltages with respect to ground. Symbol VDD min 1.6 typ 2.5 max 3.6 Units V
*AKM assumes no responsibility for the usage beyond the conditions in this datasheet.
MS0363-E-01 -4-
2005/08
ASAHI KASEI
[AK4555]
ANALOG CHARACTERISTICS (Ta=25C; VDD=2.5V; fs=44.1kHz; Signal Frequency=1kHz; SCLK=64fs; Measurement frequency=20Hz 20kHz; unless otherwise specified) Parameter min typ max Units ADC Analog Input Characteristics: (Note 2) Resolution 20 Bits S/(N+D) 70 80 dB (-0.5dB Input) D-Range 82 89 dB (-60dB Input, A-weighted) 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 40 70 k Power Supply Rejection (Note 4) 45 dB DAC Analog Output Characteristics: Resolution 20 Bits S/(N+D) 75 85 dB D-Range 86 92 dB (-60dB Output, A-weighted) 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 1.5 1.65 Vpp Load Resistance 10 k Load Capacitance 30 pF Power Supply Rejection (Note 4) 50 dB Power Supplies Power Supply Current AD+DA PWADN= "H", PWDAN= "H" 8 13 mA AD PWADN= "H", PWDAN= "L" 4 mA DA PWADN= "L", PWDAN= "H" 4.4 mA Power down (Note 5) PWADN= "L", PWDAN= "L" 10 50 A Power Consumption AD+DA PWADN= "H", PWDAN= "H" 20 32.5 mW AD PWADN= "H", PWDAN= "L" 10 mW DA PWADN= "L", PWDAN= "H" 11 mW Power down (Note 5) PWADN= "L", PWDAN= "L" 25 125 W
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. No signal is input to AINL/R pins and "0" data is input to SDTI pin. Note 5. In case of power-down mode, all digital input including clocks pins (MCLK, SCLK and LRCK) are held to VDD or VSS. PWADN and PWDAN pins are held to VSS.
MS0363-E-01 -5-
2005/08
ASAHI KASEI
[AK4555]
FILTER CHARACTERISTICS (Ta=25C; VDD=1.6 3.6V; fs=44.1kHz; DEM1 pin = "L", DEM0 pin = "H") Parameter Symbol min ADC Digital Filter (Decimation LPF): PB 0 Passband (Note 6) 0.1dB -1.0dB -3.0dB Stopband SB 25.7 Passband Ripple PR Stopband Attenuation SA 65 Group Delay (Note 7) GD Group Delay Distortion GD ADC Digital Filter (HPF): FR Frequency Response (Note 6) -3dB -0.5dB -0.1dB DAC Digital Filter: PB 0 Passband (Note 6) 0.05dB -6.0dB Stopband SB 24.1 Passband Ripple PR Stopband Attenuation SA 54 Group Delay (Note 7) GD DAC Digital Filter + Analog Filter: Frequency Response FR 0 20.0kHz
typ 20.0 21.1 17.0 0 3.4 10 22 22.05 19.0 0.5
max 17.4 0.1 20.0 0.02 -
Units kHz kHz kHz kHz dB dB 1/fs s Hz Hz Hz kHz kHz kHz dB dB 1/fs dB
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. This is the calculated delay time caused by digital filtering. This time is measured from the input of analog signal to setting the 20 bit data of both channels on input register to the output register of ADC. This time also includes group delay of HPF. For DAC, this time is from setting the 20 bit data of both channels on input register to the output of analog signal.
DC CHARACTERISTICS (Ta=25C; VDD=1.6 3.6V) Parameter Symbol min High-Level Input Voltage 2.2VVDD3.6V VIH 70%VDD 1.6VVDD<2.2V VIH 80%VDD Low-Level Input Voltage 2.2VVDD3.6V VIL 1.6VVDD<2.2V VIL High-Level Output Voltage (Iout= -20A) VOH VDD-0.1 Low-Level Output Voltage (Iout= 20A) VOL Input Leakage Current Iin -
typ -
max 30%VDD 20%VDD 0.1 10
Units V V V V V V A
MS0363-E-01 -6-
2005/08
ASAHI KASEI
[AK4555]
SWITCHING CHARACTERISTICS (Ta=25C; VDD=1.6 3.6V; CL=20pF) Parameter Symbol min Master Clock Timing Frequency 256fs/384fs/512fs/768fs fCLK 2.048 1024fs fCLK 2.048 Duty Cycle dCLK 40 LRCK Timing Frequency fs 8 Duty Cycle Duty 45 Serial Interface Timing tSCK 1/(96fs) SCLK Period (8kHz fs 33kHz) tSCK 312.5 (33kHz < fs 50kHz) SCLK Pulse Width Low tSCKL 130 Pulse Width High tSCKH 130 (Note 8) tLRS 50 LRCK Edge to SCLK "" (Note 8) tSLR 50 SCLK "" to LRCK Edge tDSS SCLK "" to SDTO SDTI Hold Time tSDH 50 SDTI Setup Time tSDS 50 Reset Timing PWADN or PWDAN Pulse Width tPW 150 (Note 9) tPWV PWADN "" to SDTO Valid
Note 8. SCLK rising edge must not occur at the same time as LRCK edge. Note 9. These cycles are the number of LRCK rising from PWADN rising.
typ 44.1 2081
max 38.4 25.6 60 50 55 80 -
Units MHz MHz % kHz % ns ns ns ns ns ns ns ns ns ns 1/fs
MS0363-E-01 -7-
2005/08
ASAHI KASEI
[AK4555]
Timing Diagram
1/fCLK VIH VIL tCLKH tCLKL dCLK = tCLKH x fCLK x 100 = tCLKL x fCLK x 100
MCLK
1/fs VIH VIL tLRH tLRL Duty = tLRH x fs x 100 = tLRL x fs x 100
LRCK
tSCK VIH VIL tSCKH tSCKL
SCLK
Figure 1. Clock Timing
VIH VIL tSLR tLRS VIH VIL tDSS
LRCK
SCLK
SDTO tSDS
50%VD
tSDH VIH VIL
SDTI
Figure 2. Serial Interface Timing
tPW
PWDAN VIL tPW VIH VIL tPWV
PWADN
SDTO
50%VD
Figure 3. Reset & Initialize Timing
MS0363-E-01 -8-
2005/08
ASAHI KASEI
[AK4555]
OPERATION OVERVIEW System Clock Input
The AK4555 can be input MCLK=256fs, 384fs, 512fs, 768fs or 1024fs (fs is equal to or lower than 25kHz when MCLK is 1024fs). The input clock applied to the MCLK pin as internal master clock is divided into 256fs automatically. When MCLK is 1024fs, oversampling rate of D/A converter is automatically changed from 128fs to 256fs. 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 should be synchronized with MCLK. The phase between these clocks does not matter. *fs is sampling frequency. When the synchronization is out of phase by changing the clock frequencies during normal operation, the AK4555 may occur click noise. In case of DAC, click noise is avoided by setting the inputs to "0". All external clocks(MCLK, SCLK and LRCK) must be present unless PWADN=PWDAN= "L". If these clocks are not provided, the AK4555 may draw excess current and may not possibly operate properly because the device utilizes dynamic refreshed logic internally. fs 8.0kHz 16.0kHz 32.0kHz 44.1kHz 48.0kHz 256fs 2.0480MHz 4.0960MHz 8.1920MHz 11.2896MHz 12.2880MHz 384fs 3.0720MHz 6.1440MHz 12.2880MHz 16.9344MHz 18.4320MHz MCLK 512fs 768fs 1024fs 4.0960MHz 6.1440MHz 8.1920MHz 8.1920MHz 12.2880MHz 16.3840MHz 16.3840MHz 24.5760MHz N/A 22.5792MHz 33.8688MHz N/A 24.5760MHz 36.8640MHz N/A Table 1. System Clock Example SCLK 32fs 64fs 0.2560MHz 0.512MHz 0.5120MHz 1.024MHz 1.0240MHz 2.048MHz 1.4112MHz 2.822MHz 1.5360MHz 3.072MHz
For low sampling rates, outband noise causes S/N of DAC to degrade. S/N is improved by setting MCLK to 1024fs. Table 2 shows S/N of DAC output. fs MCLK S/N(fs=8kHz, A-weighted) 256fs/384fs/512fs/768fs 84dB 8kHz 50kHz 1024fs 90dB 8kHz 25kHz Table 2. Relationship among fs, MCLK frequency and S/N of DAC
MS0363-E-01 -9-
2005/08
ASAHI KASEI
[AK4555]
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. The following formats are also valid when SCLK is 64fs: 16-bit data followed by four zeros and 18-bit data followed by two zeros.
LRCK
0 1 2 3 16 17 18 19 20 21 30 31 0 1 2 3 16 17 18 19 20 21 30 31 0 1
SCLK(64fs SDTO(o) SDTI(i) 16bit SDTI(i) 18bit SDTI(i) 20bit
0 1
19 18
4
3
2
1
0
19 18
4
3
2
1
0
15 14
0
Don't Care
1 0
15 14
0
Don't Care
1 0
17 16
2
Don't Care
1 0
17 16
2
Don't Care
1 0
19 18
4
3
2
Don't Care
19 18
4
3
2
Don't Care
2
3
8
9
10
11
12
13
14
15
0
1
2
3
8
9
10
11
12
13
14
15
0
1
SCLK(32fs) SDTO(o) SDTI(i)
0 15 14 8 7 6 5 4 3 2 1 0 15 14 8 7 6 5 4 3 2 1 0
0
15 14
8
7
6
5
4
3
2
1
0
15 14
8
7
6
5
4
3
2
1
0
Lch Data
Rch Data
Figure 4. Audio Interface Timing
De-emphasis filter
The DAC of AK4555 includes the digital de-emphasis filter (tc=50/15s) by IIR filter. This filter corresponds to three frequencies (32kHz, 44.1kHz and 48kHz). The de-emphasis filter selected by DEM0 and DEM1 pins is enabled for input audio data. The de-emphasis is also disabled at DEM1 pin = "L" and DEM0 pin = "H". DEM1 pin DEM0 pin Mode L L 44.1kHz L H OFF H L 48kHz H H 32kHz Table 3. De-emphasis filter control
Digital High Pass Filter
The AK4555 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).
MS0363-E-01 - 10 -
2005/08
ASAHI KASEI
[AK4555]
Power-down & Reset
The ADC and DAC of AK4555 are placed in the power-down mode by bringing each power down pin, PWADN, PWDAN = "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 5 shows the power-up sequence when the ADC is powered up before the DAC power-up.
PWADN
2081/fs
ADC Internal State PWDAN
Normal Operation
Power-down
Init Cycle
Normal Operation
DAC Internal State
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 5. Power-up Sequence
MS0363-E-01 - 11 -
2005/08
ASAHI KASEI
[AK4555]
SYSTEM DESIGN
Figure 6 shows the system connection diagram. An evaluation board[AKD4555] is available which demonstrates
application circuit, optimum layout, power supply arrangements and measurement results.
0.1u
Rch In
+
1 Lch In
+
VCOM AINR AINL VSS VDD DEM0 DEM1 SDTO
AOUTR 16 AOUTL 15
2 3
Analog Supply 1.6 3.6V
AK4555
Top View
PWDAN 14 PWADN 13 SCLK 12 MCLK 11 LRCK 10 SDTI 9
Reset Reset
4
10u + 0.1u
5 6 7 8
Controller
Mode Control
Analog Ground
System Ground
Figure 6. System Connection Diagram Example Notes: - When AOUT drives some capacitive load, some resistor should be added in series between AOUT and capacitive load.
MS0363-E-01 - 12 -
2005/08
ASAHI KASEI
[AK4555]
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 AK4555 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 0.1F ceramic capacitor is connected to VDD and VSS pins, normally. VCOM is a signal ground of this chip. A 0.1F ceramic capacitor attached to VCOM pin 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 and VCOM pins in order to avoid unwanted coupling into the AK4555. 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 is 2's compliment. The AK4555 samples the analog inputs at 64fs. The digital filter rejects noise above the stop band except for multiples of 64fs. The AK4555 includes an anti-aliasing filter (RC filter) to attenuate a noise around 64fs. 4. Analog Outputs The analog outputs are also single-ended and centered around the VCOM voltage. The output 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.
MS0363-E-01 - 13 -
2005/08
ASAHI KASEI
[AK4555]
Layout Pattern Example
AK4555 requires careful attention to power supply and grounding arrangements to optimize performance. (Please refer to AKD4555 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 AK4555 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 AK4555. 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 AK4555, a 10pF ceramic capacitor on MCLK pin is connected with digital ground. 0.1F ceramic capacitors of VDD-VSS pins and VCOM-VSS pins should be located as close to the AK4555 as possible. And these lines should be the shortest connection to pins.
2. 3.
4.
0.1u
Rch In
+
1 VCOM Lch In
+
AOUTR 16 AOUTL 15
2 AINR 3 AINL
Analog Supply 1.6 3.6V
AK4555
PWDAN 14 PWADN 13
4 VSS
+ 10u 0.1u
Reset &Power-down
51 51 10P 51
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 7. Layout Pattern Example
MS0363-E-01 - 14 -
2005/08
ASAHI KASEI
[AK4555]
PACKAGE
16pin TSSOP (Unit: mm)
*5.00.1 1.050.05
16
9 *4.40.1 A 6.40.2 0.170.05 Detail A 0.10.1 0-10 0.50.2 0.10
Epoxy Cu Solder (Pb free) plate 2005/08 - 15 -
1 0.220.1
8 0.65
0.13 M
Seating Plane
NOTE: Dimension "*" does not include mold flash.
Package & Lead frame material
Package molding compound: Lead frame material: Lead frame surface treatment:
MS0363-E-01
ASAHI KASEI
[AK4555]
MARKING
AKM 4555VT XXYYY
1) 2)
3) 4)
Pin #1 indication Date Code : XXYYY (5 digits) XX: Lot# YYY: Date Code Marketing Code : 4555VT Asahi Kasei Logo
Revision History
Date (YY/MM/DD) 04/11/24 05/08/08 Revision 00 01 Reason First Edition Spec Change Page 7 Contents Switching Characteristics tSCK(min): 312.5ns 1/(96fs) or 312.5ns
MS0363-E-01 - 16 -
2005/08
ASAHI KASEI
[AK4555]
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.
MS0363-E-01 - 17 -
2005/08

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