Low Power, 3.3 V, RS-232 Line Drivers/Receivers ADM3202/ADM3222/ADM1385

Transcription

1 a FEATURES kbps Data Rate Specified at 3.3 V Meets EIA-3E Specifications. F Charge Pump Capacitors Low Power Shutdown (ADM3E and ADM35) DIP, SO, SOIC, SSOP and TSSOP Package Options Upgrade for MAX3/3 and LTC35 E Protection to IEC-- (.) on RS-3 Pins (ADM3 Only) kv: Contact Discharge 5 kv: Air-Gap Discharge APPLICATIONS General Purpose RS-3 Data Link Portable Instruments Printers Palmtop Computers PDAs GENERAL DESCRIPTION The ADM3/ADM3/ADM35 transceivers are high speed, -channel RS-3/V. interface devices which operate from a single 3.3 V power supply. Low power consumption and a shutdown facility (ADM3/ ADM35) makes them ideal for battery powered portable instruments. The ADM3/ADM3/ADM35 conforms to the EIA- 3E and CCITT V. specifications and operates at data rates up to kbps. Four external. µf charge pump capacitors are used for the voltage doubler/inverter permitting operation from a single 3.3 V supply. The ADM3 contains additional enable and shutdown circuitry. The EN input may be used to three-state the receiver outputs. The input is used to power down the charge pump and transmitter outputs reducing the quiescent current to less than.5 µa. The receivers remain enabled during shutdown unless disabled using EN. The ADM35 contains a driver disable mode and a complete shutdown mode. The ADM3 is available in a -lead DIP, narrow and wide SOIC as well as a space saving -lead TSSOP package. The ADM3 is available in -lead DIP, SO and in -lead SSOP and TSSOP. The ADM35 is available in a -lead SSOP package, which is pin compatible with the LTC35 CG. Low Power, 3.3 V, RS-3 Line Drivers/Receivers ADM3/ADM3/ADM35 FUNCTIONAL BLOCK DIAGRAMS T IN T IN R OUT R OUT T IN T IN R OUT R OUT T IN T IN R OUT R OUT EN DD C C 3.3V TO.V 3.3V INPUT C3.3V C.V TO.V C INVERTER C C C T T 3.3V TO.V ADM3 T OUT R IN R IN C5 ON EACH RS-3 INPUT 3.3V INPUT C3.3V C.V TO.V C C INVERTER C C T T R R R R ADM3 3.3V TO.V T OUT R IN R IN C5 ON EACH RS-3 INPUT 3.3V INPUT C.V TO.V C INVERTER T T R R ADM35 C5 C3 C.3V T OUT R IN R IN ON EACH RS-3 INPUT REV. B Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. One Technology Way, P.O. Box 9, Norwood, MA -9, U.S.A. Tel: 7/ Fax: 7/3-73 Analog Devices, Inc.,

2 ADM3/ADM3/ADM35 SPECIFICATIONS ( = 3.3 V.3 V, C C =. F. All specifications T MIN to T MAX unless otherwise noted.) Parameter Min Typ Max Unit Test Conditions/Comments DC CHARACTERISTICS Operating Voltage Range V Power Supply Current.3 3 ma No Load ma R L = 3 kω to Shutdown Supply Current..5 µa LOGIC Input Logic Threshold Low, V INL. V T IN Input Logic Threshold High, V INH. V T IN Output Voltage Low, V OL. V I OUT =. ma Output Voltage High, V OH. V I OUT = ma Logic Pull-Up Current 5 µa T IN = to * Output Leakage Current ± µa Receivers Disabled RS-3 RECEIVER EIA-3 Input Voltage Range 3 3 V EIA-3 Input Threshold Low.. V EIA-3 Input Threshold High.. V EIA-3 Input Hysteresis. V EIA-3 Input Resistance kω RS-3 TRANSMITTER Output Voltage Swing (RS-3) ± 5. ± 5. V = 3.3 V. All Transmitter Outputs Loaded with 3 kω to Ground Output Voltage Swing (RS-5) ± 3.7 V = 3. V Transmitter Output Resistance 3 Ω = V, V OUT = ± V RS-3 Output Short Circuit Current ± 5 ma Output Leakage Current ± 5 µa = Low, V OUT = V TIMING CHARACTERISTICS Maximum Data Rate kbps = 3.3 V, R L = 3 kω to 7 kω, C L = 5 pf to Receiver Propagation Delay pf. One Tx Switching TPHL. µs TPLH. µs Transmitter Propagation Delay 3. µs R L = 3 kω, C L = pf Receiver Output Enable Time ns Receiver Output Disable Time ns Transmitter Skew 3 ns Receiver Skew 3 ns Transition Region Slew Rate Measured from 3 V to 3 V or 3 V to 3 V, = 3.3 V V/µs R L = 3 kω, C L = pf, T A = 5 C *ADM35: Input leakage current typically µa when T IN =. Specifications subject to change without notice. REV. B

3 ADM3/ADM3/ADM35 ABSOLUTE MAXIMUM RATINGS* (T A = 5 C unless otherwise noted) V to V (.3 V) to V V to V Input Voltages T IN V to (,.3 V) R IN ± 3 V Output Voltages T OUT ± 5 V R OUT V to (.3 V) Short Circuit Duration T OUT Continuous Power Dissipation Power Dissipation N mw (Derate mw/ C above 5 C) θ JA, Thermal Impedance C/W Power Dissipation R mw (Derate mw/ C above 5 C) θ JA, Thermal Impedance C/W Power Dissipation RU mw (Derate mw/ C above 5 C) θ JA, Thermal Impedance C/W Power Dissipation R mw (Derate mw/ C above 5 C) θ JA, Thermal Impedance C/W Power Dissipation RS mw (Derate mw/ C above 5 C) θ JA, Thermal Impedance C/W Power Dissipation RU mw (Derate mw/ C above 5 C) θ JA, Thermal Impedance C/W Operating Temperature Range Industrial (A Version) C to 5 C Storage Temperature Range C to 5 C Lead Temperature (Soldering, sec) C *This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. ORDERING GUIDE Model Temperature Range Package Options* ADM3AN C to 5 C N- ADM3ARN C to 5 C R-A ADM3ARW C to 5 C R- ADM3ARU C to 5 C RU- ADM3AN C to 5 C N- ADM3ARW C to 5 C R- ADM3ARS C to 5 C RS- ADM3ARU C to 5 C RU- ADM35ARS C to 5 C RS- *N = Plastic DIP; R = Small Outline; RS = Shrink Small Outline; RU = Thin Shrink Small Outline. REV. B 3

4 ADM3/ADM3/ADM35 PIN FUNCTION DESCRIPTIONS Mnemonic Function Power Supply Input: 3.3 V ±.3 V. Internally Generated Positive Supply ( V Nominal). Internally Generated Negative Supply ( V Nominal). Ground Pin. Must be connected to V. C, C External Capacitor is connected between these pins.. µf capacitor is recommended but larger capacitors up to 7 µf may be used. C, C External Capacitor is connected between these pins.. µf capacitor is recommended but larger capacitors up to 7 µf may be used. Tx IN Transmitter (Driver) Inputs. These inputs accept TTL/ levels. Tx OUT Transmitter (Driver) Outputs. These are RS-3 signal levels (typically ±9 V). Rx IN Receiver Inputs. These inputs accept RS-3 signal levels. An internal 5 kω pull-down resistor to is connected on each input. Rx OUT Receiver Outputs. These are output logic levels. EN (ADM3) Receiver Enable, Active Low. When low, the receiver outputs are enabled. When high, they are three-stated. (ADM3) Shutdown Control. Active Low. When low, the charge pump is shut down and the transmitter outputs are disabled. (ADM35) Shutdown Control. When low, the charge pump is shut down and all transmitters and receivers are disabled. DD (ADM35) Driver Disable. When low, the charge pump is turned off and the transmitters are disabled. The receivers remain active. PIN CONNECTIONS DIP (N, R Packages) C C C 3 ADM3 5 T OUT 3 R IN C 5 7 TOP VIEW (Not to Scale) R OUT T IN T IN R IN 9 R OUT EN C 3 C C 5 C 7 R IN 9 R OUT EN C C C 3 5 ADM3 TOP VIEW 7 5 T OUT R IN C (Not to Scale) 3 R OUT R IN 7 9 T IN T IN R OUT PIN CONNECTIONS DIP (RS, RU Packages) ADM3 (SSOP TSSOP) TOP VIEW 5 (Not to Scale) 3 NC = NO CONNECT 9 7 T OUT R IN R OUT NC T IN T IN NC DD C C C 3 5 ADM35 (SSOP) 9 7 T OUT R IN C R IN NC 7 9 TOP VIEW 5 R (Not to Scale) OUT T IN 3 T IN R OUT NC NC = NO CONNECT REV. B

5 Typical Performance Characteristics ADM3/ADM3/ADM35 T OUT (HIGH) Tx O/P V, V T OUT (LOW) LOAD CAPACITANCE pf LOAD CURRENT ma TPC. Transmitter Output Voltage High/Low vs. Load kbps TPC. Charge Pump, vs. Load Current 35 Tx O/P HIGH 3 5 (IMPEDANCE) Tx O/P V IMPEDANCE 5 (IMPEDANCE) Tx O/P LOW V V TPC. Transmitter Output Voltage vs. TPC 5. Charge Pump Impedance vs. Tx O/P HIGH I kbps Tx O/P V I CC ma I 3kbps Tx O/P LOW LOAD CURRENT ma 3 LOAD CAPACITANCE pf TPC 3. Transmitter Output Voltage Low/High vs. Load Current TPC. Power Supply Current vs. Load Capacitance REV. B 5

6 ADM3/ADM3/ADM35 3.3V INPUT T C C 3.3V TO.V C3.3V C5 T C.V TO.V C C INVERTER T IN T IN T T T OUT CH 5.V CH 5.V M. s CH V TPC 7. kbps Data Transmission GENERAL DESCRIPTION The ADM3/ADM3/ADM35 are RS-3 line drivers/ receivers. Step-up voltage converters coupled with level shifting transmitters and receivers allow RS-3 levels to be developed while operating from a single 3.3 V supply. technology is used to keep the power dissipation to an absolute minimum, allowing maximum battery life in portable applications. The ADM3/ADM3/ADM35 is a modification, enhancement and improvement to the AD3 AD family and its derivatives. It is essentially plug-in compatible and does not have materially different applications. CIRCUIT DESCRIPTION The internal circuitry consists of three main sections. These are:. A charge pump voltage converter. 3.3 V logic to EIA-3 transmitters 3. EIA-3 to 5 V logic receivers. Charge Pump DC-DC Voltage Converter The charge pump voltage converter consists of a khz oscillator and a switching matrix. The converter generates a ±. V supply from the input 3.3 V level. This is done in two stages using a switched capacitor technique as illustrated below. First, the 3.3 V input supply is doubled to. V using capacitor C as the charge storage element. The. V level is then inverted to generate. V using C as the storage element. C3 is shown connected between and, but is equally effective if connected between and. Capacitors C3 and C are used to reduce the output ripple. Their values are not critical and can be increased if desired. Capacitor C3 is shown connected between and. It is also acceptable to connect this capacitor between and. If desired, larger capacitors (up to µf) can be used for capacitors C C. R OUT R OUT T IN T IN R OUT R OUT T IN T IN R OUT R OUT EN DD C C 3.3V TO.V ADM3 R IN R IN ON EACH RS-3 INPUT 3.3V INPUT C3.3V C.V TO.V C C INVERTER T T R R R R ADM3 T OUT R IN R IN C5 ON EACH RS-3 INPUT 3.3V INPUT C 3.3V TO.V C5 C C3 C.V TO.V C.3V C INVERTER T T R R ADM35 T OUT R IN R IN ON EACH RS-3 INPUT Figure. Typical Operating Circuits REV. B

7 ADM3/ADM3/ADM35 INTERNAL OSCILLATOR FROM S S C S3 S C3 = Figure. Charge Pump Voltage Doubler V INTERNAL OSCILLATOR S S C S3 S C = () Figure 3. Charge Pump Voltage Inverter Transmitter (Driver) Section The drivers convert 3.3 V logic input levels into RS-3 output levels. With = 3.3 V and driving an RS-3 load, the output voltage swing is typically ± V. Receiver Section The receivers are inverting level-shifters that accept RS-3 input levels and translate them into 3 V logic output levels. The inputs have internal 5 kω pull-down resistors to ground and are also protected against overvoltages of up to ±3 V. Unconnected inputs are pulled to V by the internal 5 kω pull-down resistor. This, therefore, results in a Logic output level for unconnected inputs or for inputs connected to. The receivers have Schmitt trigger inputs with a hysteresis level of. V. This ensures error-free reception for both noisy inputs and for inputs with slow transition times. HIGH BAUD RATE The ADM3E/ADM3E feature high slew rates permitting data transmission at rates well in excess of the EIA/RS-3E specifications. RS-3 voltage levels are maintained at data rates up to kbps even under worst case loading conditions. This allows for high speed data links between two terminals or indeed it is suitable for the new generation I N modem standards which requires data rates of 3 kbps. The slew rate is internally controlled to less than 3 V/µs in order to minimize EMI interference. OUTLINE DIMENSIONS Dimensions shown in inches and (mm). -Lead Plastic DIP (N-) -Lead Narrow Body SOIC (R-A) PIN. (5.33) MAX. (.).5 (.93). (.3).75 (.9) 9. (.55). (.35)..7 (.77) (.5).5 (.5). (7.). (.). (.5).5 (.3).3 (3.3) MIN.35 (.5).3 (7.).5 (.3). (.).95 (.95).5 (.93).57 (.).97 (3.) PIN 9.9 (.5). (.).3937 (.).359 (9.).5 (.7).9 (.9).3 (.35). (.). (5.). (.75).53 (.35).99 (.5).75 (.9).9 (.5) 5.99 (.5).5 (.7). (.) -Lead Thin Shrink Small Outline (TSSOP) (RU-) -Lead Wide Body SOIC (R-). (5.).93 (.9).33 (.5).3977 (.) 9.77 (.5).9 (.3).5 (.5). (.5) 9.99 (7.).9 (7.).93 (.5).3937 (.) PIN. (.5). (.5).33 (.) MAX PIN.5 (.7).3 (.5).9 (.35).9 (.7) 5.9 (.5).5 (.5). (.3).75 (.9).79 (.).35 (.9). (.7). (.5). (.3). (.).9 (.9).3 (.35).5 (.3).9 (.3).5 (.7).57 (.) REV. B 7

8 ADM3/ADM3/ADM35 -Lead Plastic DIP (N-) -Lead Wide Body SOIC (R-).95 (3.9).5 (.7).5 (.75).9 (.35) PIN. (5.33) MAX. (.).5 (.93) 9. (.55). (.35). (.5). (7.). (.). (.5).5 (.3).3 (3.3) MIN.7 (.77).5 (.5).35 (.5).3 (7.).5 (.3). (.).95 (.95).5 (.93) PIN.99 (7.).9 (7.) 9.3 (.5).9 (.35).93 (.5).3937 (.).9 (.7) 5.9 (.5) C7 /(B). (.3). (.).5 (.7).9 (.9).3 (.35).5 (.3).9 (.3).5 (.7).57 (.) -Lead Thin Shrink Small Outline (TSSOP) (RU-) -Lead Shrink Small Outline (SSOP) (RS-). (.).5 (.).95 (7.5).7 (.9).77 (.5).9 (.3).5 (.5). (.5) PIN. (5.3).5 (5.).3 (7.9).3 (7.) PIN. (.5). (.5).33 (.) MAX.7 (.9). (.73).7 (.7). (.7).5 (.5). (.3).75 (.9).79 (.).35 (.9). (.7). (.5). (.3). (.5).5 (.5).9 (.9).5 (.7).37 (.9). (.559) Revision History Location Page / Data Sheet changed from REV. A to REV. B. Changes to Specifications page PRINTED IN U.S.A. REV. B