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| a FEATURES 460 kbit/s Transmission Rate Single +5 V Power Supply Compatible with RS-232 Input/Output Levels 0.1 F Charge Pump Capacitors One Driver and One Receiver On-Board DC-DC Converter 4.2 V Output Swing with +5 V Supply Low Power BiCMOS: 500 A ICC Ultralow Power (1 A) Shutdown Mode 10-Lead SOIC Package APPLICATIONS Mobile Telephones Palmtop Computers PDAs Portable Instrumentation GPS Receivers Craft PortTM Tiny RS-232 Transceiver for Portable Applications ADM101E FUNCTIONAL BLOCK DIAGRAM 0.1 F + 0.1 F + VCC C1+ GND C1- 0.1 F + V- 1 2 3 +5V TO -5V VOLTAGE INVERTER 10 9 +5V ADM101E T1 R1 8 SD 7 TOUT 6 RIN TIN 4 ROUT 5 GENERAL DESCRIPTION The ADM101E is a single channel RS-232 driver and receiver in the Analog Devices Craft Port series, designed to operate from a single, +5 V supply. A highly efficient charge-pump voltage inverter generates an on-chip -5 V supply, which eliminates the need for a negative power supply for the driver and permits RS-232 compatible output levels to be developed using charge pump capacitors as small as 0.1 F. A shutdown input disables the charge pump and puts the device into a low power shutdown mode, in which the current consumption is typically less than 1 A. The transmitter is disabled during shutdown but the receiver remains functional. An epitaxial BiCMOS construction minimizes power consumption to 3 mW and also guards against latch-up. Overvoltage protection is provided allowing the receiver inputs to withstand continuous voltages in excess of 30 V. In addition, all I-O pins have ESD protection to levels greater than 15 kV. The ADM101E is available in a 10-lead SOIC package, which makes it ideal for serial communications in small, portable applications such as palmtop computers and mobile telephones, where a full, RS-232 serial interface is not required, but compact size and low power drain are paramount. Craft Port is a trademark of Analog Devices, Inc. REV. 0 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 which 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 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 (c) Analog Devices, Inc., 1999 ADM101E-SPECIFICATIONS otherwise noted.) Parameter Output Voltage Swing Min 3.5 3.25 Typ 4.2 4.2 0.5 1.85 1 2.5 1 0.8 1 +15 2.2 2.4 0.2 5 2.6 7 0.4 Max VCC Power Supply Current (Unloaded) VCC Power Supply Current (Loaded) VCC Power Supply Current (Shutdown) Input Logic Threshold Low, VINL Input Logic Threshold High, VINH Input Leakage Current RS-232 Input Voltage Range RS-232 Input Threshold Low RS-232 Input Threshold High RS-232 Input Hysteresis RS-232 Input Resistance TTL/CMOS Output Voltage Low, VOL TTL/CMOS Output Voltage High, VOH Propagation Delay Instantaneous Slew Rate1 Transition Region Slew Rate Baud Rate Output Resistance RS-232 Output Short Circuit Current NOTES 1 Sample tested to ensure compliance. Specifications subject to change without notice. (VCC = +5 V 10%, C1 = C2 = 0.1 F. All specifications TMIN to TMAX unless Units V V mA mA A V V A V V V V k V V s V/s V/s kB mA Test Conditions/Comments VCC = 5 V 5%, TOUT Loaded with 3 k to GND VCC = 5 V 10%, TOUT Loaded with 3 k to GND No Load, TIN = VCC or GND TOUT Loaded with 3 k to GND SD Input = VCC 2.4 -15 0.8 3 3.5 0.25 25 11 460 300 25 60 IOUT = 1.6 mA IOUT = -1.0 mA RS-232 to TTL CL = 10 pF, RL = 3 k-7 k, TA = +25C RL = 3 k, CL = 1000 pF Measured from +3 V to -3 V or Vice Versa RL = 3 k, CL = 1 nF VCC = 0 V, VOUT = 2 V ABSOLUTE MAXIMUM RATINGS* (TA = +25C unless otherwise noted) ORDERING GUIDE Model ADM101EARM Temperature Range -40C to +85C Package Description SOIC Package Option RM-10 VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +6 V V- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +0.3 V to -6 V Input Voltages Driver Input TIN . . . . . . . . . . . . . . -0.3 V to (VCC, +0.3 V) Receiver Input RIN . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 V Output Voltages Driver Output TOUT . . . . . . . . (VCC, +0.3 V) to (V-, -0.3 V) Receiver Output ROUT . . . . . . . . . . . -0.3 V to (VCC +0.3 V) Short Circuit Duration TOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous Power Dissipation RM-10 (Derate 12 mW/C Above +70C) . . . . . . . 1488 mW Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . . +135C/W Operating Temperature Range Industrial (A Version) . . . . . . . . . . . . . . . . -40C to +85C Storage Temperature Range . . . . . . . . . . . . -65C to +150C Lead Temperature Soldering Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . +215C Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . +220C ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . >2000 V ESD Rating (I-O Pins) . . . . . . . . . . . . . . . . . . . . . . . . . 15 kV *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. -2- REV. 0 ADM101E PIN FUNCTION DESCRIPTION Pin No. 1 2 3 4 5 6 7 8 9 10 PIN CONFIGURATION GND 1 C1- V- 2 3 10 VCC 9 C1+ SD TOUT Mnemonic GND C1- V- TIN ROUT RIN TOUT SD C1+ VCC Function Ground Pin. Must be connected to 0 V. Negative Terminal of C1 (if C1 is Polarized Capacitor). Internally Generated Negative Supply Voltage. Driver Input (3 V to 5 V TTL/CMOS Logic Levels). Receiver Output (3 V to 5 V TTL/CMOS Logic Levels). Receiver Input (EIA-232 Signal Levels). Driver Output (EIA-232 Signal Levels). Shutdown Input. Logic 1 on this input puts the ADM101E into low power shutdown mode. Positive Terminal of Charge Pump Capacitor (if C1 is Polarized Capacitor). Positive Power Supply, Nominally +5 V. ADM101E TOP VIEW (Not to Scale) 8 7 TIN 4 ROUT 5 6 RIN Typical Performance Characteristics 0 14 CHARGE PUMP VOLTAGE - Volts -1 12 10 -2 IDD - mA 0 8 -3 6 -4 4 -5 2 -6 5 10 15 CURRENT - mA 20 25 0 0 500 1000 1500 2000 2500 LOAD CAPACITANCE - pF 3000 3500 Figure 1. Charge Pump Voltage vs. Current Figure 2. IDD vs. Load Capacitance @ 460 kbps REV. 0 -3- ADM101E 6 5 4 SLEW RATE - Volts/ s TX HI 40 30 SERIES 1 20 10 0 -10 -20 SERIES 2 3 TXO/P - Volts 2 1 0 -1 -2 -3 -4 -5 0 500 1000 1500 LOAD CAPACITANCE - pF 2000 2500 TX LO -30 -40 0 100 200 300 400 DATA RATE - kbps 500 600 Figure 3. Transmitter Output Voltage vs. Load Capacitance @ 460 kbps Figure 5. Slew Rate vs. Data Rate 6 TX HI 4 TX OUTPUT VOLTAGE 5 4 TX HI 3 2 1 0 -1 -2 TX LO -3 TX LO 2 TXO/P HI & LO 0 -2 -4 -4 7 -6 0 1 2 3 4 VCC - Volts 5 6 -5 0 2 4 6 8 10 LOAD CURRENT - mA 12 14 Figure 4. Tx Output Voltage vs. Supply Figure 6. Transmitter Output Voltage vs. Load Current -4- REV. 0 ADM101E GENERAL DESCRIPTION Charge Pump Capacitors And Supply Decoupling The ADM101E is an RS-232 compatible line driver/receiver in the Analog Devices Craft Port series, containing one driver (transmitter) and one receiver. It is ideal for serial communication in small portable devices such as mobile telephones, palmtop personal computers and personal digital assistants, where a full, RS-232 serial interface is not required, and only Tx and Rx lines are required for low speed communication between devices. The ADM101E operates from a single, +5 V supply, and generates its own, on-chip, -5 V power supply, thus removing the need for a negative power supply for the driver. CIRCUIT DESCRIPTION For proper operation of the charge pump, the capacitors should have an equivalent series resistance (ESR) less than 1 . As the charge pump draws current pulses from VCC, the VCC decoupling capacitor should also have low ESR. The VCC decoupling capacitor and V- reservoir capacitor should also have low ESR because they determine how effectively ESD pulses are clamped to VCC or V- by the on-chip clamp diodes. Tantalum or monolithic ceramic capacitors are suitable for these components. If using tantalum capacitors, do not forget to observe polarity. Transmitter (Driver) Section The internal circuitry consists of three main sections. These are: 1. A charge pump dc-to-dc converter. 2. 5 V logic to EIA-232 driver. 3. EIA-232 to 5 V logic receiver. Charge Pump DC-DC Converter The driver converts 5 V logic input levels into RS-232 compatible output levels. With VCC = +5 V and driving an EIA-232 load, the output voltage swing is typically 4.2 V. Receiver Section The dc-dc converter generates a negative supply voltage from the +5 V supply, thus removing the need for a separate -5 V rail. It consists of an on-chip 200 kHz oscillator, switching matrix and two external capacitors, as shown in Figure 7. S1 VCC S2 GND INTERNAL OSCILLATOR + C1 S3 + S4 GND C2 V- = -VCC The receivers are inverting level-shifters that accept EIA-232 input levels and translate them into 5 V logic output levels. The inputs have internal 5 k pull-down resistors to ground and are also protected against overvoltages of up to 25 V. The guaranteed switching thresholds are 0.8 V minimum and 2.8 V maximum. An unconnected receiver input is pulled to 0 V by the internal 5 k pull-down resistor. This, therefore, results in a Logic 1 output level for unconnected inputs or for inputs connected to GND. The receivers have Schmitt trigger input with a hysteresis level of 0.25 V. This ensures error-free reception for both noisy inputs and for inputs with slow transition times. SHUTDOWN INPUT Figure 7. Charge Pump DC-DC Converter When S1 and S2 are closed, S3 and S4 are open, and C1 charges to +VCC. S1 and S2 are then opened, while S3 and S4 are closed to connect C1 across C2, dumping charge into C2. Since the positive terminal of C2 is at ground, a negative voltage will be built up on its negative terminal with each cycle of the oscillator. This voltage depends on the current drawn from C2. If the current is small, the voltage will be close to -VCC, but will fall as the current drawn increases. The shutdown input allows the ADM101E to be put into an ultralow power mode where the dc-dc converter is switched off and the transmitter is disabled. The receiver remains active during shutdown. Logic 0 at this input enables the ADM101E, while a Logic 1 at this input shuts down the ADM101E. REV. 0 -5- ADM101E OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 10-Lead SOIC (RM-10) C3444-2-3/99 0.120 (3.05) 0.112 (2.84) 0.043 (1.09) 0.037 (0.94) 0.022 (0.56) 0.021 (0.53) 0.124 (3.15) 0.112 (2.84) 10 6 0.124 (3.15) 0.112 (2.84) 1 5 0.199 (5.05) 0.187 (4.75) PIN 1 0.0197 (0.50) BSC 0.122 (3.10) 0.110 (2.79) 0.038 (0.97) 0.030 (0.76) 6 0.006 (0.15) 0.016 (0.41) SEATING 0 PLANE 0.011 (0.28) 0.002 (0.05) 0.006 (0.15) 0.003 (0.08) -6- REV. 0 PRINTED IN U.S.A. |
Price & Availability of ADM101E
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