HT9201A/B Simple Tone Dialer Features • • • Patent Number: 113235(R.O.C.), 5424740(U.S.A.) • • Operating voltage: 2.0V~5.5V Low standby current 4×4 keyboard matrix 3.58MHz crystal or ceramic resonator Four flash key times selectable for the HT9201B General Description vide good performance for regular DTMF dialing with low distortion output and minimal external components. The HT9201A/B tone dialers are CMOS LSIs designed for telecommunication systems. The HT9201A is for mute output whereas the HT9201B is for flash output. Both dialers pro- Selection Table Function F1,F2,F3,F4 A,B,C,D Flash T ime (ms) DT MF Output MUT E XMUT E HT9201A √ √ — √ 16 DIP HT9201B — √ 600/300/200/90 — 16 DIP Item Package Pin Assignment 1 3rd Dec ’97 HT9201A/B Keyboard Information Block Diagram Pin Description Pin Name C1~C4 R1~R4 I/O I/O Internal Connection Description CMOS IN/OUT These pins form a 4×4 keyboard matrix which can perform keyboard input detection and dialing specification setting functions. When the chip is in the standby mode the column group (C1~C4) remains low whereas the row group (R1~R4) is set high for key input detection. An inexpensive single contact 4×4 keyboard can be used as an input device. Pressing a key connects a single column to a single row, and actuates the system oscillator which result in a dialing signal output. If more than two keys are pressed at a time, no response occurs. The key-in debounce time is 20ms. Refer to the keyboard information for keyboard arrangement. 2 3rd Dec ’97 HT9201A/B Pin Name I/O X1 I X2 O Internal Connection Description The system oscillator consists of an inverter, a bias resistor and the necessary load capacitor on chip. Connecting a standard 3.579545MHz crystal or ceramic resonator to the X1 OSCILLATOR and X2 terminals can implement the oscillator function. The oscillator is turned off in the standby mode, and is actuated whenever a keyboard entry is detected. XMUTE O NMOS OUT XMUTE is an NMOS open drain structure pulled to VSS during dialing signal transmission. Otherwise, it is an open circuit. XMUTE is used to mute the speech circuit when transmitting the dial signal. MUTE O CMOS OUT The output is low when no keypad input is entered and it becomes high during dialing sequence. The timing diagram is shown in the operation timing. FLASH O CMOS OUT This pin is a CMOS output structure from which the chip receives the flash key (F1~F4) signals to break the telephone line for a flash time. TEST I CMOS IN Pull-High VDD I — Positive power supply, 2.0V~5.5V for normal operation VSS I — Negative power supply For IC chip test only Approximate internal connection circuits 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 75°C *Note: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only. Functional operation of this device at these or any other conditions above those indicated in the operational sections of this specification is not implied and exposure to absolute maximum rating conditions for extended periods may affect device reliability. 3 3rd Dec ’97 HT9201A/B (Ta=25°C) Electrical Characteristics Symbol Test Conditions Parameter VDD Min. Typ. Max. Unit 2 — 5.5 V — 0.6 2 mA — — 1 µA Conditions VDD Operating Voltage — IDD Operating Current 2.5V ISTB Standby Current 2.5V No load, no entry VIL Input Low Voltage — — VSS — 0.2VDD V VIH Input High Voltage — — 0.8VDD — VDD V IXMO XMUTE Leakage Current — VXMUTE=12V No entry — — 1 µA IOLXM XMUTE Sink Current 2.5V VXMUTE=0.5V 1 — — mA IOH1 Keypad Pin Source Current 2.5V VOH=0V –4 — –40 µA IOL1 Keypad Pin Sink Current 200 400 — µA TDB Key-in Debounce Time — FOSC=3.5795MHz — 20 — ms FOSC System Frequency — Crystal=3.5795MHz 3.5759 3.5795 3.5831 MHz Keypad entry No load 2.5V VOL=2.5V (FOSC=3.5795MHz, Ta=25°C) Tone Mode Electrical Characteristics Symbol Test Conditions Parameter VDD Conditions — — Min. Typ. Max. Unit 0.45VDD — 0.7VDD V 0.1 — — mA 0.12 0.155 0.18 Vrms VTDC DTMF Output DC Level ITOL DTMF Sink Current VTAC DTMF Output AC Level RL DTMF Output Load 2.5V THD≤–23dB 5 — — kΩ ACR Column Pre-emphasis 2.5V Row group=0dB 1 2 3 dB THD DTMF Signal Distortion 2.5V RL=5kΩ — –30 –23 dB 2.5V VDTMF=0.5V — Row group, RL=5kΩ V12 + V22+ … + Vn 2 ⁄ √ Vi 2 + Vh 2 ) THD (Distortion) (dB) = 20 log ( √ Vi, Vh: Row group and column group signals V1, V2, ... Vn: Harmonic signals (BW=300Hz~3500Hz) 4 3rd Dec ’97 HT9201A/B Functional Description Keyboard matrix • F1, F2, F3, F4 C1~C4 and R1~R4 form a keyboard matrix. The keyboard arrangement for each of the HT9201 series are shown in the Keyboard Information. The flash keys can be selected with different flash times as shown in the following table. Flash time selection table Tone frequency Tone Name Key Flash Time (ms) F1 600 Actual F2 300 200 90 Output Frequency (Hz) Specified % Error R1 697 699 +0.29% F3 R2 770 766 –0.52% F4 R3 852 847 –0.59% R4 941 948 +0.74% C1 1209 1215 +0.50% C2 1336 1332 –0.30% C3 1477 1472 –0.34% C4 1633 1645 +0.73% Keyboard operation Note: % Error does not contain the crystal frequency drift Key definition • 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ∗, #, A, B, C, D keys These are the dialing number input keys for normal operation. Timing Diagrams 5 3rd Dec ’97 HT9201A/B Application Circuits Application circuit 1 6 3rd Dec ’97 HT9201A/B Application circuit 2 7 3rd Dec ’97