HT8950 Voice Modulator Features • • • • • • Operating voltage: 2.4~4.0V On-chip SRAM Robot function Vibrato function 8kHz sampling rate 7-step level shifting • • • • • 8-bit A/D and D/A converters LED indicator with voice level Push button selection or electronic mode Few external components required 16-pin/18-pin DIP package • • • Audio system Speech system Telephone system Applications • • • Toys Mixers Recorders General Description SW0, SW1 and SW2 for electronic direct selection and ROB, TGD, TGU and VIB for push button selection. The HT8950 is a single chip CMOS LSI voice modulator. It provides 7 steps to shift the frequency of an input voice, producing a dramatical change in the output. The HT8950 includes a built-in microphone amplifier with an internal bias, an 8-bit A/D converter, a built-in SRAM as well as a current output type 8-bit D/A converter. The 8-bit A/D and D/A converters with a sampling rate of 8kHz ensures a high quality and high S/N ratio output voice. The chip provides an LED indicator which flashes with the volume of the input voices. It is offered in a 16-pin or 18-pin DIP package. The HT8950 provides two special effects: Vibrato and Robot. The Vibrato effect is generated by alternating the frequency of an input signal up and down at a rate of 8Hz. The Robot function, on the other hand, converts an input voice into a Robot voice. Both effects can be selected depending on which pin is triggered, either ROB or VIB. For the output frequency level shifting, the chip provides 7 steps which can be selected from the two groups of pins namely, 1 5th May ’98 HT8950 Pin Assignment Block Diagram 2 5th May ’98 HT8950 Unit: µm Pad Coordinates Pad No. X Y Pad No. X Y 1 2 3 4 5 6 7 8 9 –957.0 –957.0 –957.0 –957.0 –957.0 –957.0 –962.0 –161.5 200.5 720.5 423.5 210.0 –87.0 –299.5 –596.5 –815.0 –747.5 –747.5 10 11 12 13 14 15 16 17 18 732.0 984.0 956.5 956.5 956.5 530.5 345.50 –33.50 –287.50 –774.0 –675.0 –400.0 374.5 671.5 765.5 765.5 765.5 765.5 Chip size: 2350 × 2080 (µm)2 ∗ The IC substrate should be connected to VSS in the PCB layout artwork. Pin Description (18 Pin Version) Pin No. Pin Name I/O Internal Connection Description 1 SW0 I Pull-High Function setting pin (for electronic setting) 2 SW1 I Pull-High Function setting pin (for electronic setting) 3 SW2 I Pull-High Function setting pin (for electronic setting) 4 VSS I — Negative power supply (GND) 5 AO O — Internal amplifier output 6 AIN I — Internal amplifier input (inverted) 7 VDD O — Positive power supply 8 LAMP O NMOS Lamp output (brightness changes with voice volume) Open Drain 9 AUDIO O PMOS Audio output Open Drain 10 Vref I — Internal amplifier reference voltage 11 TS I — For IC test only 12 Fvib O — Vibrato frequency control 13 OSC2 O — Oscillator output 14 OSC1 I — Oscillator input 15 VIB I Pull-High Switch to Vibrato mode (toggle) 3 5th May ’98 HT8950 Pin No. Pin Name I/O Internal Connection Description 16 TGU I Pull-High Switch to Upward step mode 17 TGD I Pull-High Switch to Downward step mode (internal pull-high) 18 ROB I Pull-High Switch to Robot mode (internal pull-high) 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 2.4 3.0 4.0 V — 2.0 10 mA — — 580 mV mA VDD Operating Voltage — IOP Operating Current 3V VIN Input Signal 3V ILAMP Lamp Sink Current 3V VOL=1.3V 5.0 9.5 — AV OPA Gain Value 3V Open loop — 2000 — IO Audio Output Voltage 3V During silence — –1.0 — mA VIH “H” Input Voltage — — 0.7VDD — — V VIL “L” Input Voltage — — — — 0.3VDD V fOSC Oscillating Frequency 3V — 512 — kHz No load, fOSC=640kHz — ROSC=47kΩ 4 5th May ’98 HT8950 Functional Description the frequency of an input signal. The voice modulation is selected and determined by the SW0~SW2 inputs. The HT8950 is a single chip LSI designed for voice modulation. It provides 7 steps to shift the frequency of an input voice signal up and down. The chip is also equipped with two special effects; Vibrato and Robot. Input Step Mode SW2 SW1 SW0 The HT8950 includes a built-in amplifier, 8-bit A/D converter and current output type of 8-bit D/A converter in addition to a built-in SRAM. The brightness of an LED indicator changes with the volume of the input voice signal. Power on initial The HT8950 enters the Robot state right after power is initially switched on. Robot state The system goes into the Robot state after the ROB pin is triggered or power is turned on. In this mode, an input voice can be converted into a robot voice. Speed Ratio 1 1 1 Controlled by TGU Notes and TDG 1 1 0 UP3 2 1 0 1 UP2 8/5 1 0 0 UP1 4/3 0 1 1 NORMAL 0 1 0 DN1 8/9 0 0 1 DN2 4/5 0 0 0 DN3 2/3 1 Notes: The TGU switch elevates by one step mode, and the TGD switch, on the other hand, falls one step mode step by step as shown: Vibrato An output voice will be generated with a vibrato effect when the VIB pin is triggered, regardless of what state the system is in. The vibrato effect is toggle activated. In other words, when a voice output is playing with a vibrato effect, this effect can be eliminated by retriggering the VIB pin. The rate of vibrato effect can be changed by adjusting the resistance of the external resistor between the OSC2 and Fvil pins. • The system changes to the Robot state after the ROB pin is triggered, regardless of what state the system is in. • A voice output is accompanied with a vibrato effect after the VIB pin is triggered, regardless of what state the system is in. LED indicator The HT8950 provides a LAMP pin to drive an external LED. The brightness of LED changes with the volume of the input voice signal. Voice modulation The HT8950 provides an 8-bit A/D and a D/A converters with a sampling rate of 8kHz, ensuring a voice output of high quality and with a high S/N ratio. The chip includes 7 steps to shift 5 5th May ’98 HT8950 Application Circuits 16-pin version with an LM386 power amplifier and a 6V power supply 6 5th May ’98 HT8950 18-pin version with an LM386 power amplifier and a 6V power supply 7 5th May ’98 HT8950 16-pin version with a transistor output stage and a 6V power supply 8 5th May ’98 HT8950 18-pin version with a transistor output stage and a 6V power supply 9 5th May ’98 HT8950 16-pin version with a TDA2822 power amplifier and a 6V power supply 10 5th May ’98 HT8950 18-pin version with a TDA2822 power amplifier and a 6V power supply 11 5th May ’98