ST3917

ST3917A STMICROELECTRONICS | Alldatasheet

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SPEECH - TONE/PULSE DIALER - LED INDICATOR July 1996 SPEECH CIRCUIT .2 TO 4 WIRES CONVERSION .PRESENT THE PROPER DC PATH FOR THE LINE CURRENT AND THE FLEXIBILITY TO ADJUST IT AND ALLOW PARALLEL PHONE OPERATION .SYMMETRICAL HIGH IMPEDANCE MICRO- PHONE INPUTS SUITABLE FOR DYNAMIC, ELECTRET OR PIEZOELECTRIC TRANSDUCER .ASYMMETRICAL EARPHONE OUTPUT SUIT- ABLE FOR DYNAMIC TRANSDUCER .LINE LOSS COMPENSATION FIXED INTER- NALLY BY A.G.C. .INTERNAL MUTING TO DISABLE SPEECH DURING DIALING AND EXTERNAL MUTING TO DISABLE TRANSMIT AMPLIFIER DURING CONVERSATION MODE .LED INDICATOR EITHER FOR KEYBOARD ILLU- MINATION (OR ON-LINE INDICATION) DURING DIALING AND CONVERSATION OR FOR TONE MODE INDICATION, THROUGH MU/MFI PIN DIALER CIRCUIT .STORE UP TO 32 DIGITS FOR LAST NUMBER REDIAL BUFFER, LNR IS INHIBITED IF THERE ARE MORE THAN 32 DIGITS STORED .ALLOW MIXED MODE DIALING IN PULSE MODE .PACIFIER TONE PROVIDES AUDIBLE INDI- CATION OF VALID KEY PRESSED IN A BUZZ- ER OR/AND IN THE EARPHONE .TIMED PABX PAUSE / 10PPS PULSE RATE .MAKE/BREAK RATIO : 40/60 (ST3917A) AND 33/67 (ST3917B) .4 SELECTABLE OPTIONS ON FLASH DURA- TION AND SOFTSWITCH INHIBITION IN ONE OF THE OPTION WITH 100ms FLASH TIMING .2 SELECTABLE OPTIONS : TRANSMIT MUTE TOGETHER WITH LED FOR KEYBOARD ILLUMI- NATION OR LED FOR TONE MODE INDICATION .CONTINUOUS TONE FOR EACH DIGIT UNTIL KEY RELEASE .USES INEXPENSIVE 3.579545MHz CERAMIC RESONATOR .POWERED FROM TELEPHONE LINE, LOW OPERATING VOLTAGE FOR LONG LOOP AP- PLICATION

DESCRIPTION

The device consists of the speech and the dialer func- tions. It provides the DC line interface circuit that termi- nates the telephone line, analog amplifier for speech transmission and necessary signals for either DTMF and pulse dialing. When mated with a tone ringer, a complete telephonecan be producedwith just two ICs. TheDClineinterfacecircuit developsitsownlinevoltage acrossthedeviceandit is adjustablebyexternalresistor to suit different country’s specification. A built-in LED driver can deliver excess line current to external LED indicator(s) during dialing and speech mode. The LED(s) can be used either for keyboard illumination purpose or for tone mode indication during softswitch and mixed mode dialing by connecting MU/MFI pin to VDDandGND oranyrowrespectively.The LEDcurrent is limited to 17mA (typical). The speech network provides the two to four wires inter- face, electronic switching betweendialing and speechand automaticgain control on transmit and receive. The dialing network buffersup to 32 digits into the LND memorythatcan be laterredialedwith asinglekeyinput. Users can store all 13 signalling keys and access several unique functions with single key entries. These functions include : Pause, Last Number Dialled (LND), Softswitch and Flash. (see Figure 1). The FLASH key simulatesa hookflash to transfercalls or to activate other special features provided by the PABX or central office. The PAUSE key stores a timed pause in the number sequence. Redial is then delayed until an outside line can be accessed or some other activities occur before normal signalling resumes. A LND key automatically redials the last number dialed. Adedicatedpin MU/MFI is used to select the muting for transmit amplifier and lighted dial LED for keyboard illumination or a LEDindicator for tonemode indication. The SEL pin allows selection of any one of the four possible Flash duration options. DIP28 (Plastic Package) ORDER CODES : ST3917AN - ST3917BN SO28 (Plastic Package) ORDER CODES : ST3917AD - ST3917BD

Table 1. When redialing in the tone mode, each ration (inter signal delay) is 90ms.

SEL (Input, Pin 4) This is an option selectable pin for four Flash duration. The four options are summarised in the table 2. For option 1, softswitch feature is inhibited. It means redialed by the LND key in pulse mode will not repeat the softswitch and subsequent digits, only pulse digits are dialed out. Table 2 :Options Selectable for Flash Duration Options SEL Flash (ms) Softswitch 1V DD 100 Inhibited

2 GND 600 Enable

3 Any Row 300 Enable

4 Any Col 100 Enable

OSC (Input, Pin 5) Only one pin is needed to connect the ceramic resonator to the oscillator circuit. The other end of the resonator is connected to GND. The nominal resonator frequency is 3.579545MHzand any de- viation from this standard is directly reflected in the Tone output frequencies. The ceramic resonator provides the time reference for all circuit functions. A ceramic resonator with tolerance of±0.25% is recommended. PULSE (Output, Pin 6) This is an output consisting of an open drain N- channel device. During on-hook, pulse output pin is in high impedance and once off-hook, it will be pulled high by external resistor. MODE/PT (Input, Pin 7) Input (MODE). MODE determines the dialer’s de- fault operating mode. When the device is powered up or the hookswitch input is switched from on- hook (V DD ) to off-hook (GND), the default deter- mines the signalling mode. A VDD connection defaults to tone mode operation and a GND con- nection defaults to pulse mode operation. When dialing in the pulse mode, a softswitch fea- ture will allow a change to the tonemode whenever the * or softswitch key (TONE) is depressed. Sub- sequent * key inputs will cause the DTMF code for an * to be dialed. The softswitch will only switch from pulse to tone. The phone will be in pulse mode only after returning to on-hook and back to off- hook. Redialed by the LND key will repeat the softswitch unless the softswitch redial feature is inhibited. Output (PT). Pacifier Tone Output. In pulse mode, all valid key entries activate the pacifier tone. In tone mode, any non DTMF entry (FLASH, PAUSE, LND, TONE) activates the pacifier tone. The paci- fier tone provides audiblefeedback,confirmingthat the key has been properly entered and accepted. It is a 500Hz square wave activated upon accep- tance of valid key input after the 32ms debounce time. The square wave terminates after 75ms typically or when the valid key is no longer present. The pacifier tone signal is simultaneously sent to the earphone and the buzzer. The buzzer can be removed with- out affecting this function. The resistor value set on MODE/PT pin determines the level of the pacifier tone in the earphone. HKS (Input, Pin 8) This is the hookswitch input to the device. It is a CMOS input with a high pull up internal resistance and must be switched high or open for on-hook operation and low for off-hook operation. A transi- tion on this input causes the on-chip logic to initial- ize, terminating any operation in progress at the time. The signalling mode defaults to the mode selected at MODE/PT pin. Figures 2, 3 and 4, 5 illustrate the timing for this pin. GND (Pin 9) GNDis the negative lineterminal of the device.This is the voltage reference for all specifications. RXOUT, GRX, RXIN (Pins 10, 11 and 12) The receive amplifier has one inputRXIN anda non inverting output RXOUT. Amplification from RXIN to RXOUT is typically 31dB and it can be adjusted between 21dB and 41dB to suit the sensitivity of the earphone used. The amplification is propor- tional to the external resistor connected between GRX and RXOUT. For the hearing impaired, a specific application to offer 17dB additional gain at 3kHz is permitted. IREF (Pin 13) An external resistor of 3.6kΩ connected between IREF and GND will set the internal current level. Any change of this resistor value will influence the microphone gain, DTMF gain, earphone gain and sidetone level. VCC (Pin 14) VCC is the positive supply of the speech network. It can be stabilized by a decoupling capacitor be- tween V CC and GND. The VCC supply voltage may also be used to supply external peripheral circuits. PIN DESCRIPTION (continued) ST3917A - ST3917B

LED (Output, Pin 15) When the MU/MFI pin is connected to either VDD or GND, the LED connected to the LED pin, which functions as a keyboard illumination or off-hook indicator, will light up when the telephone is off- hook. When the MU/MFI pin is connectedto anyrow pins, the LED connected to LED pin functions as a tone mode indicator. From minimum operating line current up to 20mA, I LN -ICC is sourced into the LED with a maximum current limit of 18mA. For line current more than 20mA, this sourced current is limited at 18mA (typical). ILINE(Pin 16) A recommended external resistor of 20Ω is con- nected between ILINE and GND. Changing this resistor value will influence the microphone gain, DTMF gain, sidetone, maximum output swing on LN and the DC characteristics, especiallyin the low voltage region. LN (Pin 17) LN is the positive line terminal of the device. REG (Pin 18) The internal voltage regulator has to be decoupled by a capacitor from REG to GND. The DC charac- teristics can be changed with an external resistor connected between LN and REG or between REG and ILINE. GTX, MIC-, MIC+(Pins 19, 20, 21) The device has a symmetrical microphone inputs. The amplification from microphone inputs to LN is 51dB at 15mA line current and it can be adjusted between 43 and 51dB. The amplification is propor- tional to the external resistor connected between GTX and REG. GDTMF (Pin 22) When the DTMF input is enabled, the microphone inputs and the receive amplifier input will be muted and the dialing tone will be sent on the line. The voltage amplification from GDTMF to LN is 40dB. Final output level on the LN can be adjusted via the external resistor connected between GDTMF and GND through a decouplingcapacitor. A confidence tone is sent to the earphone during tone dialing. The attenuation of the confidence tone from LN to RXOUT is -32dB typically. The level of the confi- dence tone in the earphone can be increased by adjusting the resistor connected between GDTMF and GRX pins, the possible range is 20dB. VDD (Pin 23) VDD is the positive supply for the dialing circuit and it must meet the maximum and minimum voltage requirements. MU/MFI (Input, Pin 24) A logic low input to this pin will disable the transmit amplifier of the speech circuit. MUTE efficiency is greater than 60dB. An open circuit to this pin will enable the transmit amplifier. In this case, LED is used for keypad lighting. A connection to any row will disable the transmit mute function and the LED connected to the LED pin is used for tone mode indication. Table 3 :Logic of MU/MFI Pin Indicator MU/MFI Pin Transmit Muting LED at Pin 15 OPEN Active Lighted Dial Indicator GND Muted Lighted Dial Indicator Any Row Not Available Tone Mode Indicator PIN DESCRIPTION (continued) ST3917A - ST3917B

5 OSC

• 0# Flash Tone/Pulse Pause LND 3.58MHz Ceramic RMFCMF C14 R14 C10 ST3917A/B D12 R15 LA LB R20RGTX R21 C20 C11 GTX ILINE REG RXIN GND R24 R25 LN Secret 3917-03.EPS BLOCK DIAGRAM ST3917A - ST3917B

Symbol Parameter Value Unit VLN Positive Line Voltage Continuous 12 V ILN Line Current 140 mA VDD Logic Voltage 7V VI Maximum Voltage on PULSE, SEL, HKS, MODE, Ri, Ci, MU/MFI and OSC Pins GND(-0.3) VDD (+0.3) V Toper Operating Temperature -25, +70 °C Tstg Storage Temperature -40, +125 °C Ptot Total Power Dissipation 700 mW 3917-01.TBL

ELECTRICAL CHARACTERISTICS

(ILN = 10mA to 120mA, f = 1kHz, Tamb =2 5°C, VDD = 3V ; unless otherwise specified) Symbol Parameter Test Conditions Min. Typ. Max. Unit VLN Line Voltage (see Figure 6) I LN = 4mA ILN = 15mA ILN = 120mA ILN = 15mA, RA = 68kΩ ILN = 15mA, RB = 39kΩ 3.15 2.60 3.60 3.50 3.20 4.10 2.70 3.85 7.00 3.70 4.70 V V V V V V DD Logic Voltage (see Figure 6) Tone mode Pulse mode 2.50 2.00 6.00 6.00 V V IDD Supply Current into VDD (see Figure 6) VDD = 3V Tone mode Pulse mode 600 300 900 600 µA µA ICC Supply Current into VCC (see Figure 6) ILN = 15mA 1.3 mA ILED Supply Current to LED (see Figure 6) ILN = 10 - 20mA ILN = 20 - 120mA 10 ILN - ICC 24 mA mA VMR Memory Retention Voltage (see Figure 7) VDD = 3V 1.5 V IMR Memory Retention Current (see Figure 7) VDD =3 V 1 µA IS Off-Hook Standby Current (see Figure 6) VDD = 3V 100 250 µA IPL Pulse Output Sink Current (see Figure 6) VOUT = 0.5V 1 3 mA IPO Pacifier Tone Sink/Source Current (see Figure 6) VOUT = 0.5V(Sink) VOUT = 2.5V(Source) 1.00 0.60 3.00 1.00 mA mA VIL HKS, Mode, Keyboard Inputs Low 0.3xV DD V VIH HKS, Mode, Keyboard Inputs High 0.7xV DD V G TX Transmit Gain (see Figure 9) V MIC = 2mV RMS ILN = 15mA, RGTX = 68kΩ ILN = 60mA, RGTX = 68kΩ 49.5 52.5 dB dB AGTX Transmit Gain Variation (see Figure 9) ILN = 15mA, VMIC = 2mV RMS R GTX = 43kΩ R GTX = 27kΩ 0d B dB dB D TX Transmit Distortion (see Figure 9) ILN = 15mA, VLN =1 VRMS 2% N TX Transmit Noise (see Figure 9) I LN = 15mA, VMIC = 0V -72 dBmp ZMIC Microphone Input Impedance (see Figure 8) 50 64 80 k Ω G DTMF DTMF Gain (see Figure 10) R DTMF = 2.25kΩ , C DTMF = 22nF 37 39 41 dB C DTMF DTMF Confidence Tone Attenuation (see Figure 10) -34 -31.5 -29 dB VDTMF DTMF level on the line (see Figure 10) High Frequency Group Low Frequency Group R DTMF = 2.25kΩ , C DTMF = 22nF -8 -10 dBm dBm PEI Pre-emphasis (see Figure 10) 1 2 3 dB DIS DTMF Output Distortion (see Figure 10) 5 8 % 3917-02.TBL ST3917A - ST3917B

Symbol Parameter Test Conditions Min. Typ. Max. Unit ZDTMF DTMF Attenuation Pin Impedance 25 32 39 k Ω G RX Receive gain (see Figure 11) V INP = 4mV RMS , R E = 300Ω ,R GRX =100kΩ ILN = 15mA ILN = 60mA 29.5 23.0 31.0 25.0 32.5 27.0 dB dB AGRX Receive Gain Variation (see Figure 11) VINP = 4mV RMS , R E = 300Ω ,ILN = 15MA R GRX = 10KΩ R GRX = 300kΩ -20 -20 +10 10 dB dB dB D RX Receive Distortion (see Figure 11) ILN = 15mA, RGRX =100kΩ R E = 150Ω ,VEAR = 0.25VRMS R E = 300Ω ,VEAR = 0.45VRMS R E = 450Ω ,VEAR = 0.55VRMS N RX Receive Noise (see Figure 11) I LN = 15mA, RE = 300Ω R GRX = 100kΩ ,VINP =0 V 200 µV ZOUT Receive Output Impedance (see Figure 11) ILN = 15mA 35 Ω VPT Pacifier Tone Level on Earphone (see Figure 11) ILN = 15mA R P = ∞ R P = 430kΩ 600 mV RMS mV RMS TKD FKS KRU KRD Keyboard Interface Keypad Debounce Time Keypad Scan Frequency Keypad Pullup Resistance Keypad Pulldown Resistance See Figures 4 and 5 250 100 500 ms Hz kΩ Ω TRIS TR TPSD TISD TDUR Tone Mode Tone Output Rise Time Tone Signalling Rate Presignal Delay Intersignal Delay Tone Output Duration See Figures 2 and 3 5.55 5m s 1/sec ms ms ms TPT FPT PR TB TM IDP PDP Pulse Mode Pacifier Tone Duration Pacifier Tone Frequency Pulse Rate Break Time : ST3917A ST3917B Make Time : ST3917A ST3917B Interdigital Pause Predigital Pause : ST3917A ST3917B See Figures 4 and 5 500 820 ms Hz PPS ms ms ms ms ms ms ms Option Selectable Symbol Parameter Option 1 SEL = VDD Option 2 SEL = GND Option 3 SEL = ROW Option 4 SEL = COL Unit tFLASH Timed Hook Flash (see Figures 2 and3) 100 600 300 100 ms Notes :1. All inputs unloaded. Quiescent mode (oscillator off). 2. Pulse output sink current for VOUT = 0.5V at VDD = 3V. 3. Pacifier tone sink current for VOUT = 0.5V, source current for VOUT = 2.5V at VDD = 3V. 4. Memory retention voltage is the point where memory is guaranteed but circuit operation is not. Proper memory retention is guaranteed if either the minimum IMR is provided or the minimum VMR . The design does not have to provide both the minimum current and voltage. 5. Option 1 is with softswitch inhibition. 3917-02.TBL ELECTRICAL CHARACTERISTICS (continued) (ILN = 10mA to 120mA, f = 1kHz, Tamb =2 5°C, VDD = 3V ; unless otherwise specified) ST3917A - ST3917B

During on-hook all keypad inputs are high imped- ance internally and it requires very low current for memory retention.At anytime,row inputs are initial- ized atlogic level 1 and column inputsare initialized at logic level 0 at off-hook. The circuit verifies that a valid key has been entered by alternately scan- ning the Row and Column inputs. If the input is still valid following 32ms of debounce,the digitis stored into memory, and dialing begins after a pre-signal delay of approximately 40ms measured from the initial key closure. Output tone duration is shown in Table 1. The device allows manual dialing of an indefinite number of digits, but if more than 32 digits are dialed, LND will be inhibited. Table 4 :DTMF Output Frequencies (Hz) Key Input Std Frequency Output Frequency %i n Deviation Row 1 Row 2 Row 3 Row 4 Column 1 Column 2 Column 3 697 770 852 941 1209 1336 1477 699.1 766.2 847.4 948 1215.9 1331.7 1471.9 +0.31 -0.49 -0.54 +0.74 +0.57 -0.32 -0.35 Normal Dialing D D D ... Normal dialing is straight forward, all keyboard entries will be stored in the buffer and signalled in succession. Hook Flash D Flash D ... Hook flash may be entered into the dialed sequence at any point by keying in the function key, FLASH. When a FLASHkey is pressed, no further key inputs will be accepteduntilthe hookflashfunctionhasbeen dialed.Thekeyinputfollowing aFLASH will bestored as the initial digit of the new number (overwriting the numberdialed beforethe FLASH) unlessit is another FLASH.FLASHkey pressedimmediatelyafterhook- switch or LND will not clear the LND buffer unless digits are entered following the FLASH key. Flash LND not cleared LND Flash LND not cleared LND Flash D1 D2 LND buffer will contain D1, D2 Last Number Dialed Off-Hook LND Last number redialing is accomplished by entering the LND key at off-hook or after the FLASH key, the subsequent LND keys pressed will be ignored. Sequence Digit Emitted OFF-HOOK, D1, D2, ON-HOOK D1, D2 OFF-HOOK, LND, LND, ON-HOOK D1, D2 OFF-HOOK, D3, D4, LND, ON-HOOK D3, D4 OFF-HOOK, LND, ON-HOOK D3, D4 Last Number Dialed Inhibition Last number redialing by LND key is inhibited if there are more than 32 digits stored. Last Number Dialed Cascading Digits dial after the LND will cascade into the LND buffer for the next redialing. In cascade operation, the keyboard is inhibited upon pressing the LND key, the LND output must be completed before acceptance of any key entry. Sequence Digit Emitted OFF-HOOK, D1, D2, ON-HOOK D1, D2 OFF-HOOK, LND, D3, D4, ON-HOOK D1, D2, D3, D4 OFF-HOOK, LND, ON-HOOK D1, D2, D3, D4 Pause Off-Hook D Pause D ... A pause may be entered into the dialed sequence at any point by keying in the special function key, PAUSE. Pause inserts a 3.1 seconds (T one mode) or 3.4 seconds (Pulse mode) delay into the dialing sequence. The total delay, including predigit and post digit pauses as shown in Table 5. Table 5 :Special Function Delays Function First / Auto Delay (second) Pulse Tone SOFT- SWITCH First Auto 0.2 PAUSE First Auto 2.6 3.4 3.0 3.1 Each delay shown in Table 5 represents the time required from the time the special function key is depressed until a new digit is dialed. The time is considered ”FIRST” key if all previous inputs have been completely dialed. The time is considered ”AUTO” if in redial, or if previous digits dialing is still in progress. ST3917A - ST3917B

Led Indicator / Tone Mode Indication When the MU/MFI (Pin 24) is connected to any row of the keypad input, the LED connected to Pin 15 (LED) becomes a Tone mode indicator. The LED indicator is used in the following conditions : - At Tone mode, LED will light up at off-hook. The LED will turn off only when the telephone goes on-hook. Example :Tone mode OFF-HOOK (LED turns on) <TONE> D1, D2, D3 ON-HOOK (LED turns off) OFF-HOOK (LED turns on) <TONE> LND ON-HOOK (LED turns off) - At Pulse mode after off-hook, LED is off during pulse dialing. When dialing is followed by the ”*” or ”TONE” softswitchkey depressed,the LED will light up immediately at the softswitch after pulse dialing is completed to indicate the signalling mode change from pulse to tone. After returning to on-hook and back to off-hook, the device will be in pulse mode and then LED is turned off. Redialing from LND memory buffer will repeat the softswitch, i.e. mixed mode redialing, the LED will light up to indicate the switch to tone mode or tone dialing. The LED will turn off only when the telephone goes on-hook or is reset by the Flash key Examples :Pulse mode a) OFF-HOOK (LED is off) <Pulse> D1, D2 (LED remains off),”*” <Tone> (LED turns on), D3, D4 ON-HOOK or Flash (LED turns off) b) OFF-HOOK (LED is off) <Pulse> LND <Pulse> D1, D2 (LED remains off), ”*” <Tone> (LED turns on) D3, D4, ON-HOOK or Flash (LED turns off) - At Pulse mode, after off-hook, LED is off during pulse dialing. When switching the T one/Pulse me- chanical switch to Tone mode, LED will turn on. Example :Pulse mode OFF-HOOK (LED is off) <Pulse> D1, D2 Switch ”Tone/Pulse” mechanical switch to Tone mode (LED turns on) <Tone> D3, D4, ON-HOOK (LED turns off) The function of the LED for Tone mode indicator is described in the timing waveform in Figures 2, 3, 4 and 5. DEVICE OPERATION (continued) Keyboard Scan DTMF Output (Pin 17) P ULS E Output LED Keyboard Inp ut ONOFFON Tflas h KEYBOARD S CAN

1 FLASH * 3

Dial Sequence 1 * FLASH 3 3 : Debounce Time 3917-04.EPS Figure 2 :Tone Mode Timing with Lighted Dial LED (Pin 24 to VDD or GND) ST3917A - ST3917B

(Pin 17) P ULSE Output LED Keyb oa rd Inp ut ONOFFON Tflash KEYBOARD S CAN Dial S equ enc e 1 * FLASH 3 3 : Debounce Time 3917-06.EPS Figure 4 :Pulse Mode Timing with Lighted Dial LED (Pin 24 to VDD or GND) LND Keyb oa rd Scan DTMF Output (Pin 17) P ULSE Output LED Keyb oa rd Inp ut ONOFFON Tflash KEYBOARD S CAN

1 FLAS H *

D i al Sequence 1 * FLASH 3 : De bounce TimeLND OFF 3917-07.EPS Figure 5 :Pulse Mode Timing with Tone Indicator Using ”*” or ”Tone” Key Keyb oard Scan DTMF Output (Pin 17) P ULSE Output LED Keyb oard Input ONOFFON Tflas h KEYBOARD SCAN Dial Sequence 1 * FLASH 3 3 : Debounce Time 3917-05.EPS Figure 3 :Tone Mode Timing with Tone Indicator (Pin 24 to any row) ST3917A - ST3917B

I REF V CC MU/MFI V DD GDTMF MIC+ MI C- GTX REG LN ILINE LED ST3917A/B 123 456 789 FLA SH TONE/PULSE PAUSE LND 3.58MHz 100kΩ Pulse DTMF HKS2 100kΩ4.7 F 3.6kΩ 100 F 100nF 3.3kΩ 10nF 470nF 47kΩ 10 F+ LED Zsidetone 20 Ω Mi crophone 3.9kΩ4.7nF620 ΩBAT42 470 F 5.6V Earphone Ce ramic Options 2SA1013 100k Ω 3.3kΩ BF393 5.6kΩ 150k Ω 10V 10M Ω L3240 Buzzer 24kΩ + 10 F 100nF 2.2kΩ 1 F HKS1 10 Ω A B SECRET 3917-14.EPS TYPICAL APPLICATION ST3917A - ST3917B

PM-DIP28.EPS PACKAGE MECHANICAL DATA

28 PINS - PLASTIC PACKAGE

Dimensions Millimeters Inches a1 0.63 0.025 b 0.45 0.018 b1 0.23 0.31 0.009 0.012 b2 1.27 0.050 D 37.4 1.470 E 15.2 16.68 0.598 0.657 e 2.54 0.100 e3 33.02 1.300 F 14.1 0.555 I 4.445 0.175 L 3.3 0.130 DIP28.TBL ST3917A - ST3917B

PM-SO28.EPS PACKAGE MECHANICAL DATA Dimensions Millimeters Inches A 2.65 0.104 a1 0.1 0.3 0.004 0.012 b 0.35 0.49 0.014 0.019 b1 0.23 0.32 0.009 0.013 C 0.5 0.020 c1 45 o (Typ.) D 17.7 18.1 0.697 0.713 E 10 10.65 0.394 0.419 e 1.27 0.050 e3 16.51 0.65 F 7.4 7.6 0.291 0.299 L 0.4 1.27 0.016 0.050 S8 o (Max.) SO28.TBL Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No licence is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of SGS-THOMSON Microelectronics.  1996 SGS-THOMSON Microelectronics - All Rights Reserved Purchase of I 2C Components of SGS-THOMSON Microelectronics, conveys a license under the Philips I2C Patent. Rights to use these components in a I2C system, is granted provided that the system conforms to the I2C Standard Specifications as defined by Philips. SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil -Canada - China - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco The Netherlands - Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. ST3917A - ST3917B