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AKEMD
AKEMD CONFIDENTIAL
[AK7844]
AK7844
Stereo Audio Class-D Amp with Power Booster for Piezo Speakers
GENERAL DESCRIPTION
THE AK7844 is Stereo Class-D amplifier for driving Piezo-Electric Speakers. Built-in Boost DCDC converter generates adequate high voltage for driving Piezo Speakers from Li-Ion battery. AKM state-of-the-art filter-less solution eliminates LC-filters, which are normally required at Class-D outputs. That contributes to total space saving. Class-D operation ensures higher power efficiency, and couple with Piezo Speaker that is low-powerconsumption and low-profile figure. The AK7844 is very applicable for cellular phones with piezo speakers.
FEATURES Class-D Amplifier * Piezo-Electric Speaker Driver * Single-ended analog Input * BTL output * Output voltage = 8Vrms @VDD1=8.75V * Filter-less solution * Stereo mode * Pop noise suppressor * Output short protection Boost DCDC Converter * Input voltage (Battery) = 2.7V 4.5V * Over-current protection * Over-voltage protection Boosted voltage will be 8.75V
Control function * Pre-gain amplifier -6dB +15dB, 3dB step * Built-in Second order lowpass filter at Input. * Cutoff Frequency (4kHz,8kHz,16kHz) * Power-on/off control * Over-temperature protection Operational voltage
* Adjustable by Pin (PG0, PG1 and PG2) control
* Adjustable by Pin (PG0, PG1 and PG2) control
VBAT=2.7V 4.5VDVDDI=1.65V 4.5V -30C 85C
Operational temperature Package
31pin WL-CSP (3.0mm x 3.0mm, 0.5mm pitch)
Rev.00
1-
2007/08
AKEMD
AKEMD CONFIDENTIAL
[AK7844]
BLOCK DIAGRAM
FC FC0 PG 2 PG 1 PG 0 DVDDI PDN
VBAT
Power Booster
VCOIL VFB ERRO VSS3
VDD1 INL
Pre GainL
Fc: 4/8/16kHz
LPF L
Class-D AMP L
VCLN VCLP VSS1
-6 +15dB 3dB step
VSS4 VDD2 VCRN VCRP VSS2
INR
Pre GainR VREF
LPF R
Class-D AMP R
VC
Figure 1. BLOCK DIAGRAM
Rev.00
2-
2007/08
AKEMD
AKEMD CONFIDENTIAL
[AK7844]
PIN ASSIGNMENT
A B C D E F
6
5
4
.0
3
2
1
0.25
0.5
0.25

6 5 4 3 2 1
A NC VCRP ERRO PG2 VCOIL NC
B VDD2 VCRN VSS2 VSS4 VSS3
C D VFB NC NC NC PG1 FC1 PG0 DVDDI Figure 2. Pin Assighnment
E VDD1 VCLN VSS1 VBAT FC0 PDN
F NC VCLP INL INR VC NC
Rev.00
3-
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
Pin / FUNCTION
Function No Connection pin. Connect to ground. Inductor pin for Boost DCDC. Pre Gain setting pin2 (available when I2CEN="L") Phase compensation capacitor connection pin for Boost DCDC. A4 ERRO Connect a 0.1F capacitor between VC pin and ground. A5 VCRP O Right channel Class D amp plus output (+) A6 NC No Connection pin. Connect to ground. B1 B2 VSS3 Power Booster ground pinVSS3=0V B3 VSS4 Internal analog circuit ground pinVSS4=0V B4 VSS2 I Right channel Class D amp ground pinVSS2=0V B5 VCRN O Right channel Class D amp minus output (-) B6 VDD2 Right channel Class D amp power supplyVDD2=8.75V(typ.) C1 PG0 I Pre Gain setting pin0 C2 PG1 I Pre Gain setting pin1 C3 C4 C5 NC No Connection pin. Connect to ground. C6 VFB Boosted voltege feedback pin. D1 DVDDI Digital interface powerDVDDI=1.65V4.5V D2 FC1 I SCF cutoff frequency setting pin1 D3 D4 No Connection pin. Connect to ground. D5 NC No Connection pin. Connect to ground. D6 NC Power down contorolschmitt trigger input E1 PDN I "High"poewer up"Low"power down SCF cutoff frequency setting pin2 E2 FC0 I Battery voltage inputVBAT=2.7V4.5V E3 VBAT Left channel Class D amp ground pinVSS1=0V E4 VSS1 Left channel Class D amp minus output (-) E5 VCLN O Left channel Class D amp power supplyVDD1=8.75V(typ.) E6 VDD1 F1 NC No Connection pin. Connect to ground. Voltage reference output. Connect a 0.01F capacitor between VC pin and ground. F2 VC F3 INR I Right channel analog signal input F4 INL I Left channel analog signal input F5 VCLP O Left channel Class D amp plus output (+) F6 NC No Connection pin. Connect to ground. Note 1. Digital input pins (PDN, PG2, PG1, PG0, FC1, FC0) must not be open. No. A1 A2 A3 Pin Name NC VCOIL PG2 I/O I
Unused Pins Unused pins should be configured as below. Category Pin Name NoConnection NC
Configuration GND
Rev.01
4-
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
ABSOLUTE MAXIMUM RATINGS (VSS1, VSS2, VSS3,VSS4=0V;Note 3) Parameter Symbol min max Power Supplies: Battery VBAT -0.3 6.5 (Note.4) Digital I/F DVDDI -0.3 6.5 Class-D Amp VDD1,2 -0.3 15 Input Current, Any Pin Except Supplies IIN -10 +10 Analog Input Voltage (Note 4) (Note 6) VINA -0.3 VBAT+0.3 Digital Input Voltage (Note 5) (Note 6) VIND -0.3 DVDDI+0.3 Ambient Temperature (powered applied) Ta -30 85 Storage Temperature Tstg -65 150 Note 2. All voltages are with respect to ground. Note 3. VSS1, VSS2, VSS3, VSS4 pin must be connected to the same analog ground plane. Note 4. INL,INR pin Note 5. PDN, PG2, PG1, PG0, FC1, FC0 pin Note 6. Maximum value must not exceed 6.5V even if VBAT or DVDDI is more than 6.2V.
WARNING: Operation at or beyond these limits may result in permanent damage to the device. Normal operation is not guaranteed at these extremes.
Units V V V mA V V C C
RECOMMENDED OPERATING CONDITIONS
(VSS1, VSS2, VSS3, VSS4=0V; Note 2) Parameter Symbol min typ Power Battery (Note 7) VBAT 2.7 3.6 Supplies VDD (Note 8) VDDx TBD 8.75 DigitalI/F(Note 7) DVDDI 1.65 2.8 Note 2. All voltages are with respect to ground. Note 7. Should sustain "VBAT DVDDI" condition Note 8. Supply with boosted voltage (typ. 8.75V) by the Power Booster. * AKM assumes no responsibility for usage beyond the conditions in this datasheet. max 4.5 TBD 4.5 Units V V V
DC CHARACTERISTICS
(Ta=25C; VBAT=2.7 4.5V,DVDDI = 1.654.5V,VSS1=VSS2=VSS3=VSS4=0V) Parameter Symbol min High-Level Input Voltage1 (Note 9) VIH1 70%DVDDI Low-Level Input Voltage1 (Note 9) VIL1 High-Level Input Voltage2 (Note 10) VIH2 80%DVDDI Low-Level Input Voltage2 (Note 10) VIL2 Input Leakage CurrentI Note 9. Applied to PG0, PG1, PG2. Note 10. Applied to PDN, FC1, FC2 (Summit trigger input). typ max 30%DVDDI 20%DVDDI 10 Units V V V V A
Rev.01
5-
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
ANALOG CHARACTERISTICS
(Unless otherwise noted, Ta25VBAT=3.6DVDDI=2.8VVSS1,2,3,40V, Input Signal Frequency =1kHz , Measurement Band Width =2020kHz ,PreGain=0dB , Fc= 16kHz Class-D ampu Output Load Impedance ZL=1.0uF) Parameter Condition min typ max Units No input signal. Idd T.B.D mA With output Load ShutdownCurrent PDN pin = "Low" 1.0 10 A Input Impedance PreGain Control Range PG2="Low",PG1=" Low",PG0=" Low" PG2="Low",PG1=" Low",PG0=" High" PG2="Low",PG1=" High",PG0=" Low" PG2="Low",PG1=" High",PG0=" High" PG2=" High",PG1=" Low",PG0=" Low" PG2=" High",PG1=" Low",PG0=" High" PG2=" High",PG1=" High",PG0=" Low" PG2=" High",PG1=" High",PG0=" High" VCL(R)P/VCL(R)N Input Signal=0.7Vrms VCL(R)P/VCL(R)N No input signal VCL(R)P/VCL(R)N (Note 12) Input Signal=0.5Vrms VCL(R)P/VCL(R)N (Note 12) Input Signal=0.7Vrms using an A wating filter. VCL(R)P/VCL(R)N (Note 12) Vripple=200mVpp@1kHz sinwave INLNoInput INR=2Vpp LchOutputPin monitoring. INRNoInput INL=2Vpp RchOutputPin monitoring. Class-D Amp PowerBooster C3=0.01uF, C5=C6= 0.1uF(Note 15) VBAT=2.7V INL INR 25 25 -6 -7 -4 -1 +2 +5 +8 +11 +14 TBD 70 -6 -3 0 +3 +6 +9 +12 +15 5.0 80 50 70 70 225 900 250 1000 28 275 1100 dB dB kHz ms 50 50 75 75 +15 -5 -2 +1 +4 +7 +10 +13 +16 TBD T.B.D. -30 k k dB dB dB dB dB dB dB dB dB Vrms mV dB dB
PreGain Step Size (Note 11)
Output Voltage Output Offset Voltage THD+N SNR PSRR (Note 13) Cross Talk Switching Frequency Startup Time (Note 14)
Note 11. Setting accuracy of each setting is within 1dB. Monotony is guaranteed. Note 12. Measure signals between VCL(R)N and VC L(R)P through Low-Pass-Filter (fc=20kHz). Note 13. 200mVpp@1kHz superimposed signal at VBAT pin, .and measured output. Note 14. Time period from "PDN" turns "High" to stability operation. Note 15. Refer to section "TYPICAL APPLICATION CIRCUIT".
Rev.01
6-
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
OPERATION OVERVIEW Power Control
Once PDN pin is set to "Low", all circuit will stop and AK7844 will shut down. It resumes and outputs stable signal in (TBD)ms after PDN is set to "High".
Power-Up Sequence
VBAT and DVDDI must be turned on as (1) or (2) below. (1) VBAT=DVDDI="ON" at the same time. (2) VBAT="ON" first, then DVDDI="ON". Set PDN pin to "High" when power-on. Then, PDN must be delayed at least 1us after DVDDI is set to High. Do not do them simultaneously.
VBAT DVDDI PDN pin
> 1us
Figure 3. Power-Up Sequence (1) Timing Diagram
VBAT DVDDI PDN pin
>0 > 1us
Figure 4. Power-Up Sequence (2) Timing Diagram Attention: The performance of the device will not be guaranteed after the below sequence. (3) DVDDI="ON" first, then VBAT="ON".
Rev.01
7-
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
Power-Down Sequence VBAT and DVDDI must be turned off as (4) or (5) below. (4) VBAT=DVDDI="OFF" at the same time. (5) DVDDI="OFF" first, then VBAT="OFF". Set PDN pin to "Low" when shutdown. Then, 1s wait is necessary before stopping power supply, DVDDI and VBAT. Do not do them simultaneously.
Note: When PDN pin is "High" and VBAT/DVDDI supply is suddenly cut off due to unexpected event, pop noise may be detected while sound signal is being amplified. Under such cases LSI will not be harmed. Power supply (VBAT, DVDDI) sequences are as follows.
VBAT DVDDI PDN pin
> 1us
Figure 5. Power-Down Sequence (4) Timing Diagram
///VBAT
DVDDI PDN pin
> 1us
>0
Figure 6. Power-Down Sequence (5) Timing Diagram Attention: The performance of the device will not be guaranteed after the below sequence. (6) VBAT="OFF" first, then DVDDI="OFF"
Rev.01
8-
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
Analog inputs AC-coupling capacitor is required at analog inputs. Recommended capacitance is 0.1F. This AC-coupling capacitance configures High-Pass-Filter, and used to configuration of POP NOISE SUPPRESSOR as well. Therefore, any variation of this capacitance affects both HPF cut-off frequency and POP NOISE SUPPRESSOR operation. Additional input filter is applicable. When using filter at analog input, place it before AC-coupling capacitors.
Note 16. Cut off frequency (fc) of the High-pass filter, used as decoupling before input, is caluculated by an equation, 1 / (2 x x R x C). For example, when Input impedance of INN and INP pins are 50k(typ.) and AC coupling capacitors are 0.1F, then the cut off frequency will be 31.8Hz.
Pre AMP THE AK7844 has internal Pre-Amplifier, which supports from -6dB to +15dB(3dB/step) gain range. Pre-Amplifier gain is adjusted by PG0,PG1 and PG2 like as shown below.
PG2 "Low" "Low" "Low" "Low" "High" "High" "High" "High" PG1 "Low" "Low" "High" "High" "Low" "Low" "High" "High" PG0 "Low" "High" "Low" "High" "Low" "High" "Low" "High" Pre Gain Setting Value -6dB -3dB 0dB +3dB +6dB +9dB +12dB +15dB
Table. 1 Pre Gain Setting
Class-D AMP Class-D architecture features higher efficiency and low power consumption operation. AKM filter-less solution offers Class-AB performance with Class-D efficiency and minimal board space. Pop Noise Suppressor The AK7844 features extensive pop noise suppression circuitry. Power Booster Built-in BOOST DCDC CONVERTER generates adequate high voltage for Piezo-Speaker. Input voltage range corresponds with Li-Ion battery voltage range (2.7V ~ 4.5V), and output voltage is 8.75V. Normally, output connected to and supply VDD1 and VDD2 for Class-D operation. Lowpass Filter The AK7844 has a built-in Lowpass Filter at the input side. Cutoff frequency can be adjusted by FC0 and FC1 as follows. FC0 and FC1 must be connected to either ground (VSS4) or DVDDI. FC1 FC0 CurOff Frequency "Low" "Low" 16kHz "Low" "High" 8kHz "High" "Low" 4kHz "High" "High" 4kHz Table. 2 Adjustable Cutoff Frequency of Lowpass filter
Protection
The AK7844 supports following protection circuits for protecting against any damages.
Rev.01
9-
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
Output Short-Circuit Protection In case of detecting VCL(R)P and VCL(R)N short, the AK7844 clamps peak current of Class-D output circuit without shutting down the outputs. Over-Temperature Protection The AK7844 is designed to shutdown at +150C of inside temperature so that it can be protected from heat damage. Note that the AK7844 DOES NOT support resume function from Over-Temperature Protection. Once it is activated, the AK7844 does not back in normal operation unless "PDN" is toggled ("L" "H"). Over-Current Protection Class-D amplifiers' current-limiting protection clamps the output current without shutting down the outputs. Over-Voltage Protection Boost DCDC Converter has the voltage-limiting function to avoid destrying itself.
Rev.01
10 -
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
Performance characteristics
The following various characteristics are typical characteristic data in the typical condition. It is not the one necessarily to secure the characteristic of the description.
Sinwave Single Input, Total Gain=16.9dB, Measurement Band Frequency=2020kz, Cutoff Frequency=16kHz, unless otherwise specified.
10
VBAT=4.5V CL=1.0uF
10
VBAT=3.6V CL=1.0uF
1
Vout=4Vrms Vout=2Vrms THD+N (%)
1
Vout=4Vrms
THD+N (%)
Vout=2Vrms
0.1
Vout=1Vrms
0.1
Vout=1Vrms
0.01 0.1 1 10 100 Frequency (kHz)
0.01 0.1 1 10 100 Frequency (kHz)
10
VBAT=2.7V CL=1.0uF
1
Vout=4Vrms Vout=2Vrms
THD+N (%)
0.1
Vout=1Vrms
0.01 0.1 1 10 100 Frequency (kHz)
Figure 7. Total Harmonic Distortion Plus Noise vs. Frequency
Rev.01
11 -
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
10
VBAT=4.5V CL=1.0uF
10
VBAT=3.6V CL=1.0uF
1
Fin=4kHz THD+N (%)
1
Fin=4kHz
Fin=1kHz
THD+N (%)
Fin=1kHz
0.1
Fin=10kHz
0.1
Fin=10kHz
0.01 0 1 2 3 4 5
0.01 0 1 2 3 4 5
Output Voltage (Vrms)
Output Voltage (Vrms)
10
VBAT=2.7V CL=1.0uF Fin=4kHz
1
Fin=1kHz
THD+N (%)
0.1
Fin=10kHz
0.01 0 1 2 3 4 5
Output Voltage (Vrms)
Figure 8. Total Harmonic Distortion Plus Noise vs. Output Voltage
Rev.01
12 -
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
6
VBAT4.5V,3.6V,2.7V The all same characteristic
Vin=2Vpp CL=1.0uF
18 16 14 12 Gain (dB)
VBAT4.5V,3.6V,2.7V The all same characteristic
5
VBAT=4.5V VBAT=3.6V
Vout=2Vrms CL=1.0uF
VBAT=3.6V VBAT=4.5V VBAT=2.7V
Output Voltage (Vrms)
4
VBAT=2.7V
3
10 8 6 4
2
1
2
0 0.01
0
0.1 1 Frequency (kHz) 10 100
0.1
1
10
100
Frequency (kHz)
Figure 9. " Output Amplitude vs. Frequency " & " Frequency Response "
350 300 Supply Current @ Stereo (mA) 250 200 150 100 50 0 0
Fin=1kHz CL=1.0uF
-20
VBAT=3.6V VBAT=2.7V
VBAT+0.2Vpp CL=1.0uF
-30
PSRR (dB)
VBAT=2.7V -40
VBAT=4.5V
-50 VBAT=3.6V VBAT=4.5V
1
2
3
4
5
-60 0.01
0.1
Output Voltage (Vrms)
1 Frequency (kHz)
10
100
Figure 10. " Supply Current vs. Output Voltage " & " Supply Ripple Rejection Ratio vs Frequency "
Rev.01
13 -
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
20 18 Supply Current @ Stereo (mA) 16
CL=1.0uF No Input
20 18 16 Shutdown Current (nA) 14 12 10 8 6 4 2 0 CL=1.0uF
14 12 10 8 6 4 2 0 2.6 3 3.4 3.8 4.2 4.6 Supply Voltage (V)
2.6
3
3.4
3.8
4.2
4.6
Supply Voltage (V)
Figure 11. "Supply Current vs. Supply Voltage" & "Shutdown Current vs. Supply Voltage"
PDN 2V/div
PDN 2V/div
Output Waveform 10V/div 10ms/div
Output Waveform 10V/div 10ms/div
Figure 12. "Startup Waveform" & "Shutdown Waveform"
Rev.01
14 -
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
Power Supply Input : 217Hz Duty 12% Input pin : AC open CL=1.0uF
Power Supply Input : 217Hz Duty 12% Input pin : AC open CL=1.0uF
GSM PSRR vs FREQUENCY 0 -20 -40 FFT[dB] -60 -80 -100 -120 -140 0 500 1000 1500 Frequency[Hz] VBAT Lch Rch 2000 2500
Figure 13. "GSM PSRR vs TIME" & "GSM PSRR vs Frequency"
Rev.01
15 -
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
LEVEL DIAGRAM The gain of AK7844 are determined by Pre-Amplifier, LPF and Class-D Amp, Total gain will be +16.9dB while Pre-Amplifier is default setting (PG=0). LPF gain and Class-D Amp gain are not changeable. Figure 14 shows level diagram of two example, PG=0dB and PG=+15dB.
INx Pre AMP
-3dB to +15dB 3dB step
LPF
+6dB
Class-D AMP +10.9dB
VCxN VCxP
[dBV] 25
0dBV = 1Vrms
1kHz
20
Class-D AMP maximum output with 1uF load : 5.0Vrms Output : 13.9dBV (5.0Vrms)
15
10
+10.9dB
5
+6.02dB Input (1) : -3.01dBV (0.70Vrms) *Pre Gain = 0dB Input path Limit : -3.01dBV 0dB -3.01dBV (0.70Vrms) 3.01dBV (0.70Vrms)
0
-5
- 10
+15dB
- 15
Input (2) : -18.01dBV (0.126Vrms) *Pre Gain = +15dB
- 20
Figure 14. Level Diagram *1Vrms=0dBV=2.83Vpp (sin wave)
Rev.01
16 -
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
TYPICAL APPLICATION CIRCUIT
Li-ion Battery C4 DVDDI FC1 FC0 PG2 PG1 PG0 Pre Gain ERRO PDN VFB C9 VBAT VCOIL VSS3 VDD1 VCLN C5 INL LPF
ClassD L
Piezo Speaker
L1 D1 C1
Boost DCDC
VCLP VSS1 VSS4 VDD2
C7
C6
INR VC C3
Pre Gain VREF
LPF
VCLN
Class-D R
Piezo Speaker
VCLP VSS2
C8
Figure 15 AK7844 Application Schematic Recommended external components are shown in Table. 3. Reference Type Value Manufacturer Part No. Size (mm) CoilCraft LPS3010-102ML 2.95 x2.95 x0.9 L1 Inductor 1.0uF TDK TFC252008MC-1R0 2.5 x2.0 x0.8 Diode (30V, SANYO SS1003EJ 1.6 x 0.8 x 0.6 D1 / Schottky 1A) GRM319B31C106K 3.2x1.6x0.85 Capacitor 10F / Murata C1 / Ceramic 25V GRM155B11E103KA01D 10050.50 Capacitor 0.01F / Murata C3 / Ceramic 16V C4, C5, C6, Capacitor 0.1F / GRM155B11A104KA01D 10050.50 Murata C7, C8 / Ceramic 16V GRM188B31A225KE33D 16080.80 Capacitor 0.1F / Murata C9 / Ceramic 25V Table. 3 External Recommendation Parts Chose one of inductors in Table. 3 Selection of L1, C1 and D1 are very important because they affect DCDC converter paformance directly. For stability operation, AKM recommends them described in Table. 3
Rev.01
17 -
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
1. Grounding and Power Supply Decoupling The AK7844 requires careful attention to power supply and grounding arrangements. VBAT is usually supplied from Li-Ion battery in the system. VDD1 and VDD2 are supplied from smoothed boosted voltage. VSS1, VSS2, VSS3 and VSS4 must be connected to analog ground plane. Analog and digital ground in the system should be connected together near where the supplies are brought onto the printed circuit board. Decoupling capacitors with the small value ceramic (C7,C8) should be as close to the AK7844 as possible. 2. Voltage Reference VC is a signal ground of this device. A 0.01F ceramic capacitor (C3) between VC and VSS4 pin eliminates the effects of high frequency noise. This capacitor should be as close to the VC pin as possible. Do not take out load current from the VC pin. All signals, especially clocks should be kept away from the VC pin in order to avoid unwanted coupling. 3. Class-D analog Inputs AC-coupling capacitors are necessary in series to INL and INR respectively. 4. Class-D Outputs The Class-D outputs are in BTL signal format. Locate the outputs close to the speaker to minimize interconnect resistance and capacitance to suppress noise. Match the length and pattern of the plus and minus output interconnect. Keep AK7844 or Class-D outputs away as far away as possible from the devices such as antennas that are sensitive to high frequency noise. 5. Effect on RF bands Power Booster or Class-D Outputs may affect high frequency signal outside the AK7844. Apply previous section (4. Class-D Outputs) in PCB layout. 6. Drivable Piezo Speakers The AK7844 is designed to drive typical piezo speakers but in some cases electric characteristics of the speakers differ by manufacturers. Feel free to ask us whether your speakers can be driven or not before using them. 7. Boost DCDC Converter Ceramic capacitor (C1, C9), Inductance (L1) and Schottky Diode (D1) should be located as close to the AK7844 as possible.
Rev.01
18 -
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
PACKAGE MARKING
AK7844
XXXX
1 A XXXX : Date code (4 digit)
31pin WL-CSP Package Outline (Unit : mm)
Rev.01
19 -
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
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 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. 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.
Rev.01
20 -
2007/08
ASAHI KASEI
AKM CONFIDENTIAL
[AK7844]
Revision History
Date (YY/MM/DD) 07/08/07 07/09/13 Revision Reason 00 01 addition Page 11-15 Contents First edition in English TYPICAL CHARACTERISTICS
Rev.01
21 -
2007/08

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