Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.astro.louisville.edu/software/xmtel/archive/xmtel-3.1/docs/lx200/ds232a.pdf Äàòà èçìåíåíèÿ: Wed May 10 23:56:41 2000 Äàòà èíäåêñèðîâàíèÿ: Mon Oct 1 21:53:25 2012 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï ï

DS232A Dual RS-232 Transmitter/Receiver
www.dalsemi.com

FEATURES
Compatible with LT1181A and MAX232A High data rate - 250 kbits/sec under load 16-pin DIP or SOIC package 20-pin TSSOP package for height restricted applications Operate from single +5V power Meets all EIA-232E and V0.28 specifications Uses small capacitors: 0.1 µF Optional industrial temperature range available (-40°C to +85°C)

PIN ASSIGNMENT
C1+ V+ C1C2+ C2VT2OUT R2IN 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VCC GND T1OUT R1IN R1OUT T1IN T2IN R2OUT

16-Pin DIP AND SOIC
C1+ V+ C1C2+ NC C2VNC T2OUT R2IN 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 NC VCC GND T1OUT R1IN R1OUT NC T1IN T2IN R2OUT

ORDERING INFORMATION
DS232A DS232A-N DS232AR DS232AR-N DS232AS DS232AS-N DS232AE DS232AE-N 16-pin 16-pin 16-pin 16-pin 16-pin 16-pin 20-pin 20-pin DIP DIP (Industrial) SOIC (150-Mil) SOIC (150-Mil) (Industrial) SOIC (300-Mil) SOIC (300-Mil) (Industrial) TSSOP TSSOP (Industrial)

20-Pin TSSOP

PIN DESCRIPTION
VCC GND V+ VT1IN, T2IN T1OUT, T2OUT R1IN, R2IN R1OUT, R2OUT C1+, C1C2+, C2+5-Volt Supply Ground Positive Supply Output Negative Supply Output RS-232 Driver Inputs RS-232 Driver Outputs Receiver Inputs Receiver Outputs Capacitor 1 Connections Capacitor 2 Connections

DESCRIPTION
The DS232A is a dual RS-232 driver/receiver pair that generates RS-232 voltage levels from a single +5volt power supply. Additional ±12-volt supplies are not needed since the DS232A uses on-board charge pumps to convert the +5-volt supply to ±10 volts. The DS232A is fully compliant with EIA RS-232E and V0.28/V0.24 standards. The DS232A contains two drivers and two receivers. Driver slew rates and data rates are guaranteed up to 250k bits/sec. The DS232A operates with only 0.1 µF charge pump capacitors.

OPERATION
The diagram in Figure 1 shows the main elements of the DS232A. The following paragraphs describe the function of each pin. 1 of 10 112099


DS232A

FUNCTIONAL DIAGRAM OF DS232A Figure 1

NOTE: C5 is a recommended decoupling capacitor which is the same value as C1, C2, C3, and C4. ( ) Are for TSSOP package only.

PIN DESCRIPTIONS
VCC, GND: DC power is provided to the device on these pins. V
CC

is the +5-volt input.

V+: Positive supply output (RS-232). V+ requires an external storage charge capacitor of at least 0.1 µF. A larger capacitor (up to 10 µF) can be used to reduce supply ripple. V-: Negative supply output (RS-232). V- requires an external storage capacitor of at least 0.1 µF. A larger capacitor (up to 10 µF) can be used to reduce supply ripple. T1IN, T2 IN: Standard TTL/CMOS inputs for the RS-232 drivers. The inputs of unused drivers can be left unconnected since each input has a 400 k pullup resistor. T1OUT, T2 OUT: Driver outputs at RS-232 levels. Driver output swing meets RS-232 levels for loads up to 3 k. These driver outputs provide current necessary to meet RS-232 levels for loads up to 2500 pF. 2 of 10


DS232A

R1 IN, R2 IN: Receiver inputs. These inputs accept RS-232 level signals (±25 volts) into a protected 5 k terminating resistor. Each receiver provides 0.5V hysteresis (typical) for noise immunity. R1
OUT

, R2

OUT

: Receiver outputs at TTL/CMOS levels.

C1+, C1-, C2+, C2-: Charge pump capacitor inputs. These pins require two external capacitors (0.1 µF minimum, 10 µF maximum and should be the same size as C3 and C4). Capacitor 1 is connected between C1+ and C1-. Capacitor 2 is connected between C2+ and C2-. Capacitor C1 can be omitted if +12 volts is connected directly to V+. Likewise, C2 can be omitted if -12V is connected directly to V-.

The DS232A has a two-stage on-board charge pump circuit that is used to generate ±10 volts from a single +5-volt supply. In the first stage, capacitor C1 doubles the +5V supply to +10 volts which is then stored on capacitor C3. The second stage uses capacitor C2 to invert the +10V potential to -10V. This charge is then stored on capacitor C4. The ±10-volt supplies allow the DS232A to provide the necessary output levels for RS-232 communication. The DS232A will operate with charge pump capacitors as low as 0.1 µF. Larger capacitors (up to 10 µF) can be used to reduce supply ripple.

DUAL CHARGE PUMP CONVERTERS

RS-232 DRIVERS

The two RS-232 drivers are powered by the internal ±10-volt supplies generated by the on-board charge pump. The driver inputs are both TTL and CMOS compatible. Each input has an internal 400 k=pullup resistor so that unused transmitter inputs can be left unconnected. The open circuit output voltage swing is from (V+ - 0.6) to V- volts. Worst case conditions for EIA-232E/V.28 of ±5-volt driving a 3 k=load and 2500 pF are met at maximum operating temperature and VCC equal to 4.5 volts. Typical voltage swings of ±8 volts occur when loaded with a nominal 5 k=RS-232 receiver. As required by EIA-232E and V.28 specifications, the slew rate at the output is limited to less than 30 volts/µs. Typical slew rates are 20 volts/µs unloaded and 12 volts/µs with 3 k=and 2500 pF load. These slew rates allow for bit rates of over 250k bits/s. Driver outputs maintain high impedance when power is off.

RS-232 RECEIVERS
The two receivers conform fully to the RS-232E specifications. The input impedance is typically 5 k=and can withstand up to ±25 volts with or without VCC applied. The input switching thresholds are within the ±3-volt limit of RS-232E specification with an input threshold low of 0.8 volts and an input threshold high of 2.4 volts. The receivers have 0.5 volts of hysteresis (typical) to improve noise rejection. The TTL/CMOS compatible outputs of the receivers will be low whenever the RS-232 input is greater than 2.4 volts. The receiver output will be high when the input is floating or driven between +0.8 volts and -25 volts.

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ABSOLUTE MAXIMUM RATINGS*
Absolute Maximum Ratings VCC V+ VInput Voltages TIN RIN Output Voltages TOUT ROUT Short Circuit Duration, TOUT * -0.3V to +7.0V (VCC-0.3V) to +14V +0.3V to -14V -0.3V to (VCC+0.3V) ±30V (V+ + 0.3V) to (V- - 0.3V) -0.3V to (VCC+ 0.3V) Continuous

This is a stress rating only and 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.

RECOMMENDED DC OPERATING CONDITIONS
PARAMETER Operating Supply Voltage SYMBOL VCC MIN 4.5 TYP MAX 5.5

(0°C to 70°C)
UNITS V NOTES 1

DC ELECTRICAL CHARACTERISTICS
PARAMETER Power Supply Current (No Load) Power Supply Current (3 k Load All Outputs) RS-232 Transmitters Output Voltage Swing Input Logic Threshold Low Input Logic Threshold High Maximum Data Rate Logic Pullup/Input Current Transmitter Output Resistance Output Short-Circuit Current VOR
S

(0°C to 70°C)
MIN TYP 4 15 MAX 10 UNITS mA mA NOTES

SYMBOL ICC1 ICC2

±5 0.8 250 300 ±15

±8 1.4 1.4 350 5 10M ±30 ±100 40 2.0

V V V k bits/s µA mA

2

VTTL VTTH fD IPU R
OUT

3 4

ITSC

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DC ELECTRICAL CHARACTERISTICS (continued)
RS-232 Receivers RS-232 Input Voltage Operating Range RS-232 Input Threshold Low RS-232 Input Threshold High RS-232 Input Hysteresis RS-232 Input Resistance TTL/CMOS Output Voltage Low TTL/CMOS Output Voltage High TTL/CMOS Output Short Circuit Current (VOUT=GND) TTL/CMOS Output Short Circuit Current (VOUT=VCC) V
IR

(0°C to 70°C)
±30 1.3 1.8 2.4 1 7 0.4 0.5 5 0.2 V V V V k V V mA mA 5 6

±25 0.8 0.2 3 3.5 -2 10

VRTL VRTH V
HY IN

R

VROL VROH IRSC IRSC

VCC-0.2 -10 30

AC ELECTRICAL CHARACTERISTICS
PARAMETER Transition Slew Rate Transmitter Propagation Delay TTL to RS-232 Receiver Propagation Delay RS-232 to TTL Transmitter + to - Propagation Delay Difference Receiver + to - Propagation Delay Difference SYMBOL tSR t t t t
PHLT PLHT

(0°C to 70°C)
MIN 6 TYP 12 1.3 1.5 0.5 0.6 300 100 MAX 30 3.5 3.5 1 1 UNITS V/µs µs µs µs µs ns ns NOTES 7

PHLR PLHR

tPHLT -tPLHT tPHLR -tPLHR

NOTES:
1. All voltages are referenced to ground. 2. All transmitter outputs loaded with 3 k=to ground 3. VCC = V+ = V- = 0V; VOUT = ±2V. 4. VOUT = 0V. 5. IOUT = 3.2 mA. 6. IOUT = -1.0 mA. 7. CL = 50 pF - 2500 pF; RL = 3 k=- 7 k; VCC = 5V; TA = 25°C.

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TRANSMITTER PROPAGAION DELAY TIMING Figure 2

RECEIVER PROPAGATION DELAY TIMING Figure 3

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16-PIN DIP (300-MIL)

PKG DIM A IN. MM B IN. MM C IN. MM D IN. MM E IN. MM F IN. MM G IN. MM H IN. MM J IN. MM K IN. MM

16-PIN MI N 0.740 18.80 0.240 6.10 0.120 3.05 0.300 7.62 0.015 0.38 0.120 3.04 0.090 2.29 0.320 8.13 0.008 0.20 0.015 0.38 M AX 0.780 19.81 0.260 6.60 0.140 3.56 0.325 8.26 0.040 1.02 0.140 3.56 0.110 2.79 0.370 9.40 0.012 0.30 0.021 0.53

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16-PIN SOIC (150-MIL)

PKG DIM A IN. MM A1 IN. MM A2 IN. MM B IN. MM C IN. MM D IN. MM E IN. MM E1 IN. MM H IN. MM L IN. MM

16-PIN MI N 0.053 1.35 0.004 0.10 0.048 1.24 0.012 0.30 0.007 0.17 0.386 9.80 M AX 0.069 1.75 0.010 0.25 0.062 1.57 0.020 0.50 0.011 0.28 0.393 9.98

0.050 BSC 1.27 BSC 0.150 3.81 0.230 5.84 0.016 0.40 0° 0.158 4.01 0.244 6.20 0.050 0.89 8°

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16-PIN SOIC (300-MIL)

PKG DIM A IN. MM A1 IN. MM A2 IN. MM b IN. MM C IN. MM D IN. MM E IN. MM E1 IN. MM H IN. MM L IN. MM

16-PIN MI N 0.094 2.39 0.004 0.102 0.089 2.26 0.013 0.33 0.009 0.229 0.398 10.11 M AX 0.105 2.67 0.012 0.30 0.095 2.41 0.020 0.51 0.013 0.33 0.412 10.46

0.050 BSC 1.27 BSC 0.290 7.37 0.398 10.11 0.016 0.40 0° 0.300 7.62 0.416 10.57 0.040 1.02 8°

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20-PIN TSSOP

DIM A MM A1 MM A2 MM C MM L MM e1 MM B MM D MM E MM G MM H MM phi

MI N 0.05 0.75 0.09 0.50 0.18 6.40

M AX 1.10 1.05 0.18 0.70 0.30 6.90

0.65 BSC

4.40 NOM 0.25 REF 6.25 0° 6.55 8°

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