Ordering number : EN4624B CMOS IC LC78835K, 78835KM 18 Bits Digital Filter and D/A Converter for Digital Audio Overview Package Dimensions The LC78835K and 78835KM are 18-bit digital-to-analog D/A converter CMOS ICs with an on-chip eight-times oversampling digital filter. The LC78835 and the LC78835M are pin compatible. unit: mm 3092-DIP24W [LC78835K] Features • Digital filter — 8 fs oversampling filter: 3-stage finite-impulseresponse (FIR) filter design (43rd-, 11th-, and thirdorders) — De-emphasis filter: Supports fs = 32 kHz, 44.1 kHz, or 48 kHz — Soft mute — Noise shaper — Supports double-rate sampling • D/A converter — Dynamic level-shifting 18-bit digital-to-analog converter — On-chip 2-channel D/A converter (with corresponding output) — On-chip output op-amp — Supports 384 fs, 392 fs, 448 fs, or 512 fs system clock — Single 5 V supply — Permits low-voltage operation (3.5 V) — Low-power silicon-gate CMOS process SANYO: DIP24W unit: mm 3155-MFP24 [LC78835KM] SANYO: MFP24 SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN 73696HA (OT)/N1094TH (OT)/82793JN No. 4624-1/14 LC78835K, 78835KM Specifications Absolute Maximum Ratings at Ta = 25°C, VSS = 0°C Parameter Symbol Maximum supply voltage Conditions Ratings VDD max Unit –0.3 to + 7.0 V VIN –0.3 to VDD + 0.3 V Output voltage VOUT –0.3 to VDD + 0.3 V Operating temperature Topr –30 to + 75 °C Storage temperature Tstg –40 to + 125 °C Input voltage Allowable Operating Ranges Ratings Parameter Supply voltage Symbol Conditions min VDD typ 3.5 5.0 max Unit 5.5 V Reference voltage high Vref H VDD – 0.3 VDD V Reference voltage low Vref L 0 0.3 V Operating temperature Topr –30 +75 °C DC Characteristics at Ta = –30 to +75°C, VDD = 3.5 to 5.5 V, VSS = 0 V Ratings Parameter Symbol Conditions Input high level voltage (1) VIH1 3, 4, 5, 6, 7, 13, 14, 15, 16, 17 and 18 pin Input low level voltage (1) VIL1 3, 4, 5, 6, 7, 13, 14, 15, 16, 17 and 18 pin Input high level voltage (2) VIH2 11 pin Input low level voltage (2) VIL2 11 pin Output high level voltage VOH 9 pin: IOH = –3 mA Output low level voltage VOL 9 pin: IOL = 3 mA IL *, VI = VSS, VDD Input leakage current min typ max 2.2 Unit V 0.8 0.7VDD V V 0.3VDD 2.4 V V –25 0.4 V +25 µA Note: * 3, 4, 5, 6, 7, 11, 13, 14, 15, 16, 17 and 18 pin AC Characteristics at Ta = –30 to +75°C, VDD = 3.5 to 5.5 V, VSS = 0 V Ratings Parameter Oscillation frequency Symbol fX Conditions min typ max 25 Unit XIN pin for crystal oscillator 1.0 Clock pulse width tCW With external clock input to other than XIN pin 18 MHz Clock pulse phase tCY With external clock input to other than XIN pin 40 BCLK pulse width tBCW 60 ns BCLK pulse phase tBCY 120 ns Data setup time tDS 40 ns Data hold time tDH 40 ns LRCK setup time tLRS 40 ns LRCK hold time tLRH 40 ns ns 1000 ns No. 4624-2/14 LC78835K, 78835KM Audio Input Waveforms Electrical Characteristics (1) at Ta = 25°C, AVDD = DVDD = VrefH = 5.0 V, AGND = DGND = VrefL = 0 V, unless otherwise specified Ratings Parameter Symbol Conditions D/A converter resolution RES Total harmonic distortion THD At 1 kHz, 0 dB*1 DR At 1 kHz, –60 dB Crosstalk CT At 1 kHz, 0 dB Signal-to-noise ratio S/N JIS-A Full-scale output voltage VFS Dynamic range min typ Unit max 18 Bits 0.08 90 –85 96 Pd *2 Output load resistance RL 21, 23 pin 135 5 dB dB 3.0 Power dissipation % dB VP-P 200 mW kΩ Note: 1. “0 dB” signifies full scale. 2. XIN pulse width (pin 11) 1.5 to 3.5 V, fx = 16.9344 MHz Test circuit: Based on application circuit No. 4624-3/14 LC78835K, 78835KM Electrical Characteristics (2) at Ta = 25°C, AVDD = DVDD = VrefH 3.5 V, AGND = DGND = VrefH = 0 V, unless otherwise specified Ratings Parameter Symbol Conditions D/A converter resolution RES Total harmonic distortion THD At 1 kHz, 0dB*1 DR At 1 kHz, –60 dB Crosstalk CT At 1 kHz, 0 dB Signal-to-noise ratio S/N JIS-A Full-scale output voltage VFS Dynamic range min typ Unit max 18 Bits 0.09 90 –85 96 Pd *2 Output load resistance RL 21, 23 pin 50 15 dB dB 2.1 Power dissipation % dB VP-P 75 mW kΩ Note: 1. “0 dB” signifies full scale. 2. XIN pulse width (pin 11) 1.0 to 2.5 V, fx = 16.9344 MHz Test circuit: Based on application circuit Block Diagram Pin Assignment No. 4624-4/14 LC78835K, 78835KM Pin Description Number Name 1 REFH Description Reference voltage “H” pin Normally connected to AGND via a capacitor 2 VrefH Reference voltage “H” input pin 3 MUTE Mute signal input pin Soft mute is on when high 4 D/N Normal/double-speed operation toggle Double-speed operation when high, normal operation when low 5 BCLK Bit clock input pin 6 DATA Digital audio data input pin 2’s complement code, with input from the most significant bit (MSB) 7 LRCK Left-right clock input pin Channel 1 when high, channel 2 when low 8 DVDD 9 CKOUT Digital power supply pin Clock output pin When at 392 fs: 196 fs clock When not at 392 fs: XIN-frequency clock 10 XOUT 11 XIN 12 DGND Digital ground pin 13 INITB Initialization signal input pin Initialization performed when low 14 EMP On/Off toggle for the de-emphasis filter On when high, off when low 15 FS1 32 kHz/44.1 kHz/48 kHz selector for the de-emphasis filter 16 FS2 17 CKSL1 18 CKSL2 Crystal oscillator output pin (system clock output pin) Crystal oscillator input pin (system clock input pin) FS1 L H H L FS2 L L H H fs 44.1 kHz 32 kHz 48 kHz System clock selector pin CKSL1 CKSL2 L L System Clock 384 fs L H 392 fs H L 448 fs H H 512 fs 19 VrefL Reference voltage “L” input pin 20 REFL Reference voltage “L” pin Normally connected to AGND via a capacitor 21 CH2OUT 22 AGND 23 CH1OUT 24 AVDD Channel 2 analog output pin Analog ground pin Channel 1 analog output pin Analog power supply pin No. 4624-5/14 LC78835K, 78835KM Description of Operation 1. Digital Filter The LC78835K and 78835KM perform arithmetic functions as shown in the following block diagrams. • Oversampling Constructed of twice as many interpolation filters with a cascade connection arrangement using finite-impulseresponse (FIR) filters. When operating in normal-rate mode, data is transferred through a three-stage cascading process consisting of 43rd-order, 11th-order, and third-order finite impulse response (FIR) filters connected together to produce an eight-times oversampled signal. When operating in double-rate mode, data is transferred through a two-stage cascading process consisting of 43rd-order and second-order finite-impulse-response (FIR) connected filters to give a four-times oversampled signal. For further details concerning filter characteristics, refer to page 12. • De-emphasis Digital de-emphasis is performed using a first-order infinite-impulse-response (IIR) filter. Filter supported sampling frequencies include fs = 32 kHz, 44.1 kHz and 48 kHz (frequencies are all doubled with double-rate mode). No. 4624-6/14 LC78835K, 78835KM For further details concerning filter characteristics when de-emphasis is on, refer to page 13. — De-emphasis on/off De-emphasis on: EMP pin = “H” De-emphasis off: EMP pin = “L” — Selection of filter coefficient FS1 L H H L FS2 L L H H fs 44.1 kHz 32 kHz 48 kHz • Soft Mute Soft muting is performed using the built-in digital attenuator. The attenuation amount of the attenuator circuit is as follows: 20 log (ATT/256) dB Although ATT = 0 to 256, when ATT = 0, attenuation sets to – ∞. If the MUTE pin is set to “H” level, ATT approaches 0 in single-decreasing increments and the attenuation changes towards – ∞. On the other hand, when the MUTE pin is set to the “L” level, ATT approaches 256 in single-increasing increments and the attenuation amount changes to approach 0. The approximate speed during soft mute is 1024/fs. • Noise Shaper In order to reduce noise during DF arithmetic output requantization, the first-order noise shaper is utilized. • Double-Rate Support When the D/N pin is set to “H” level, CD high-speed playback is supported. At this time, BCLK, LRCK and DATA are input at double the frequency of normal operating times. The system clock operates at 384 fs and with a clock speed of 512 fs, double-rate is supported. Note that test mode is enabled for clock speeds of 392 fs and 448fs and double-rate is not supported. Normal-rate mode: D/N pin = “L” Double-rate mode: D/N pin = “H” No. 4624-7/14 LC78835K, 78835KM 2. Initialization Initialization is necessary when power is applied or the system clock is replaced. When the INITB pin has been set to an “L” level, the supply to XIN, BCLK, and LRCK should be connected only after the supply has stabilized at the “L” level. As shown in the figure, a period greater than one LRCK cycle is required. When INITB = “L,” all 18-bit digital filter outputs set to 0, and the D/A converter’s output (CH1OUT, CH2OUT) equals 0 analog output (approximately (VREFH + VREFL)/2 electric potential). 3. System Clock This IC supports four system clock speeds including 384 fs, 392 fs, 448 fs, and 512 fs. These may be selected using the CKSL1 and CKSL2 pins. CKSL1 CKSL2 System Clock L L 384 fs L H 392 fs H L 448 fs H H 512 fs • CKOUT Pin When operating at 392 fs, clock output is 196 fs or half that of the system clock. All other speeds result in clock output equal to that of the system. No. 4624-8/14 LC78835K, 78835KM 4. Digital Audio Data Input Digital audio data supports MSB first and 2’s complement code using a 16-bit serial signal. 16-bit serial data is input from the DATA pin at the edge of BCLK rising and is input to the internal register along with readings at the rising and falling edges of LRCK. Digital Audio Data Input Timing No. 4624-9/14 LC78835K, 78835KM 5. Digital-to-Analog (D/A) Converter These chips have built-in output operational amplifiers which use two independent on-chip D/A converters for CH1 and CH2. Both use dynamic level shift, combining resistance strings (R-string D/A conversion), pulse-width modulation (PWM D/A conversion) and level shift D/A conversion modes. (See figure below.) • Resistance String (R-string) D/A Converter This 9-bit D/A converter circuit has 512 (=29) unit resistors (R) connected in series so that a potential applied to both ends is subjected to 512-way division. The two adjoining potentials V2 and V1 of the divided potentials corresponding to the values of the 9 MSBs of data (D15 to D9) are sent via a switching circuit to the PWM D/A converter. At this point, V2 – V1 = (VH – VL)/512. No. 4624-10/14 LC78835K, 78835KM • Pulse-Width Modulation (PWM) D/A Converter This is a 3-bit circuit that applies pulse width modulation to voltages V2 and V1 output from the R-string D/A converter to produce an 8-way division. Depending on the value of the data in bits D8 to D6, one of the voltages, V2 or V1, is output to the CH1OUT (or CH2OUT) pin. • Level Shift D/A Converter The variable resistors VRH and VRL are connected in series to the two ends of the R-string D/A converter resistance, configuring a 6-bit D/A conversion circuit. Depending on the values of the data in the LSBs (bits D5 to D0), VRH and VRL change as follows. (1) The sum of VRH and VRL is constant, irrespective of the data value. (2) Irrespective of the data value, VRH and VRL are in the range of 0 to 63R/512 (where R is the unit resistance of the R-string D/A converter) and resistance changes in R/512 steps in accordance with the data value. This means that the R-string D/A converter outputs, V2 and V1, each vary in the range of 0 to 63 × ∆V/512 (∆V = (VH - VL)/512) in ∆V/512 steps. — Vref H/L, REF H/L Pins The voltage on the Vref pins, used to apply the reference voltage to the resistance strings, are usually set so that VrefH = AVDD and VrefL = AGND. In addition, a 10 µF rated condenser connects REFH and AGND as well as REFL and AGND. When VrefH = 5.0 V, VrefL = 0 V, the LC78835K on-chip RH and RL resistors maximum output amplitude at 0 dB playback is output in the 3.0 Vp-p range extending from a minimum 0.6 V to maximum 3.6 V. No. 4624-11/14 LC78835K, 78835KM Filter Characteristics (theoretical values) Normal-rate mode: 8 fs oversampling Double-rate mode: 4 fs oversampling Ripple: within ±0.05 dB Attenuation amount: –40 dB or less •Normal Rate (De-emphasis Off) •Double Rate (De-emphasis Off) No. 4624-12/14 LC78835K, 78835KM Pass Band Characteristics with De-emphasis On • Normal Rate • Double Rate Sample Application Circuit Note: 1. Within the sample application circuit, DVDD connects to DGND as the digital ground, and AVDD connects to AGND as the analog ground. 2. For AVDD and VrefH, a low-impedance high-stability power supply (commercially available 3-pin regulator or compatible) should be used. 3. If 8-pin (DVDD) and 24-pin (AVDD) rise timings deviate, latch-up may occur. For this reason, no difference should exist between 8 and 24 pin power application timing. 4.A clock signal must be supplied to the XIN pin immediately after power is applied. The IC may be destroyed if the XIN pin is held either high or low when power is applied. No. 4624-13/14 LC78835K, 78835KM ■ No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury, death or property loss. ■ Anyone purchasing any products described or contained herein for an above-mentioned use shall: ① Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated with such use: ➁ Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally. ■ Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties. This catalog provides information as of July, 1996. Specifications and information herein are subject to change without notice. No. 4624-14/14