HT8656 Talking Back Features • • • • • Operating voltage: 4.5V~5.5V ADM algorithm DRAM selection: – 64K – 256K Sampling rate selection: – 32Kb – 16Kb Auto stop recording – 0.5 seconds silence is detected – Recording capacity is full • • • • • • • Built-in 2-stage microphone amplifier Built-in DRAM refresh circuit Voltage type D/A output Current type D/A output Auto record and playback Auto power-off Low power consumption • Games Applications • • Toys Education General Description The HT8656 provides a recording capacity of 2 seconds for DRAM of 64K and 8 seconds for DRAM of 256K at a 32Kb sampling rate and double recording capacity at a 16Kb sampling rate. A higher sampling rate will result in sounds of better quality but sacrifice the recording time, and vice versa. The HT8656 is a single chip CMOS LSI for talking back applications using an ADM algorithm. Functions of the IC consist of recording/playing as well as auto power off. It starts recording when a sound input is detected, and stops to play back when silence lasts 0.5 seconds during recording. The auto power off function is activated once a REC/PLAY cycle has been implemented 64 times or an interval of silence exceeds 2 minutes. 1 5th May ’98 HT8656 Pin Assignment Block Diagram 2 5th May ’98 HT8656 Pad Coordinates Chip size: 3276.6 × 3530.6 (µm)2 * The IC substrate should be connected to VDD in the PCB layout artwork. Unit: µm Pad No. X Y Pad No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 –1488.19 –1488.19 –1488.19 –1488.19 –1488.19 –1488.19 –1488.19 –1488.19 –1396.75 –1170.43 –964.69 –399.03 –145.29 1033.27 1239.01 1613.92 1277.87 906.53 653.80 –355.60 –635.51 –937.26 –1378.46 –1615.19 –1615.19 –1615.19 –1615.19 –1615.19 –1615.19 –1615.19 16 17 18 10 20 21 22 23 24 25 26 27 28 29 3 X Y 1488.19 –1615.19 1488.19 –377.19 1488.19 –124.71 1488.19 130.30 1488.19 384.05 1488.19 651.51 1488.19 1089.41 1488.19 1363.73 1436.88 1615.19 1226.57 1615.19 973.84 1615.19 723.65 1615.19 473.20 1615.19 –1052.83 1615.19 5th May ’98 HT8656 Pin Description Pin No. Pin Name I/O Internal Connection Description 1, 2 A6, A7 O CMOS DRAM address output 3~8 A5~A0 O CMOS DRAM address output 9 RASB O CMOS DRAM row address strobe 10 WRB O CMOS DRAM write enable 11 DATA I/O CMOS DRAM data input/output 12 A8 O CMOS DRAM address output 13 CASB O CMOS DRAM column address strobe 14 OSC2 O — Oscillator output 15 OSC1 I — Oscillator input 16 LEDB O LED indicator: NMOS Idle: LED is turned on Open Drain Record: LED flashes Play: LED is turned off 17 START O NMOS System start pin Open Drain 18 MOTOR O CMOS 19 VSS I — Negative power supply (GND) 20 BIAS I — For internal AMP bias de-coupling 21 AIN1 I — Internal AMP first stage input (inverted) 22 AO1 O — Internal AMP first stage output 23 AIN2 I — Internal AMP second stage input (inverted) 24 IOUT (8656A) O — Voltage type audio output for an external power AMP 24 IOUT (8656B) O — Current type audio output for an external transistor 25 VDD I — Positive power supply 26 TESTB I Pull-High For IC test only 27 16KB I Pull-High 32Kbps/16Kbps sampling rate selection: Open/high: 32Kbps Low: 16Kbps 28 MS I Pull-High 64K/256K DRAM size selection: Open/high: 64K Low: 256K Motor drive output (active high) when playing back 4 5th May ’98 HT8656 Absolute Maximum Ratings* Supply Voltage ................................. –0.3V to 6V Storage Temperature................. –50°C to 125°C Input Voltage................. VSS–0.3V to VDD+0.3V Operating Temperature............... –20°C to 70°C *Note: These are stress ratings only. Stresses exceeding the range specified under “Absolute Maximum Ratings” may cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability. (Ta=25°C) Electrical Characteristics Symbol Parameter Test Conditions VDD Conditions — Min. Typ. Max. Unit 4.5 — 5.5 V — 1.5 3.0 mA — 600 800 µA VDD Operating Voltage — IDD Operating Current 5V ISTB Standby Current 5V IO Max. AUD Source Current 5V VOH=0.6V –1.5 –3.0 — mA IOL MOTOR Source Current 5V VOH=4.5V –1 –3.5 — mA IOL LED Sink Current 5V VOL=0.5V 3.0 5.0 — mA VIH “H” Input Voltage — — 0.7VDD — VDD V VIL “L” Input Voltage — — 0 — 0.3VDD V VOUT Max. VOUT Output Voltage 5V RL>50kΩ — 1.5 — VP-P fOSC Oscillating Frequency 5V ROSC=43kΩ — 640 — kHz No load, fOSC=640kHz — Functional Description The HT8656 is a single chip LSI with an external DRAM. It is designed for talking back applications. The recording length of the IC is determined by the data rate along with the size of an external memory. Sounds coming from an external microphone are coded through an internal ADM algorithm and saved in an external memory until the memory is full or an interval of silence lasts over 0.5 seconds. Once recording is terminated, the IC will play back the recorded sounds automatically. Record function The HT8656 provides two kinds of sampling rate and DRAM size selection to determine the recording capacity. The recording capacity is determined as shown on the following table. 5 5th May ’98 HT8656 DRAM Type (MS) Sampling Rate (16KB) Recording Capacity 64Kb 32Kb 2 seconds 64Kb 16Kb 4 seconds 256Kb 32Kb 8 seconds 256Kb 16Kb 16 seconds switched off when a REC/PLAY cycle has been implemented 64 times or an interval of silence lasts over 2 minutes. Recording starts whenever a sound input is detected. It then stops once a 0.5 seconds silence is detected or the recording capacity is full. After that, talking back comes into play. Motor The HT8656 provides a motor driving pin. The motor is turned on during playing but off once talking back is terminated. Play function The HT8656 stops to play back the recorded sounds when an interval of silence lasts 0.5 seconds during recording. Its sampling rate is the same as the rate of recording sounds. LED The LED pin displays the status of the HT8656. LED is switched ON when the IC is in the standby state. Its intensity varies inversely with the sound volume when the IC is in the recording state. In the playing state, the LED is switched OFF. Power control The HT8656 provides a START pin for power control. The START pin is of high impedance and switch Q is turned off initially. After the START pin is triggered, it will remain at a low level and switch Q is turned on. The START pin is of high impedance and the chip’s power is 6 5th May ’98 HT8656 Flowchart 7 5th May ’98 HT8656 Application Circuits LM386 output • Dice form * The IC substrate should be connected to VDD in the PCB layout artwork. 8 5th May ’98 HT8656 • Package form 9 5th May ’98 HT8656 two transistor output • Dice form * The IC substrate should be connected to VDD in the PCB layout artwork. 10 5th May ’98 HT8656 • Package form 11 5th May ’98