19-1751; Rev 0; 6/00 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers Features ♦ AutoShutdown Plus (MAX3318/MAX3319) ♦ 300µA Operating Supply Current ♦ 1µA Low-Power Shutdown with Receivers Active ♦ Guaranteed 460kbps Data Rate ♦ Guaranteed 4V/µs Slew Rate ♦ RS-232 Compatible Down to 2.25V Ordering Information PART PIN-PACKAGE 0°C to +70°C 20 TSSOP MAX3316CAE 0°C to +70°C 16 SSOP MAX3316EUP -40°C to +85°C 20 TSSOP MAX3316EAE -40°C to +85°C 16 SSOP Ordering Information continued at end of data sheet. Typical Application Circuits +2.5V CBYPASS VCC 2 C1+ C2 0.1µF 6 3 V+ 4 C15 CMOS INPUT 15 0.1µF C1 0.1µF ________________________Applications Palmtop Computers Hand-Held Instruments Pagers Cellular Phones GPS Handy Terminals Hand-Held Electronic Books TEMP. RANGE MAX3316CUP MAX3319 C2+ V- 7 C4 0.1µF C2- 11 T1IN RS-232COMPATIBLE OUTPUT T1OUT 13 RS-232COMPATIBLE INPUT R1IN 8 9 R1OUT CMOS OUTPUT C3 0.1µF 5k 1 12 READY AutoShutdown Plus INVALID 10 FORCEOFF 16 FORCEON GND TO POWERMANAGEMENT UNIT VCC 14 AutoShutdown Plus is a trademark of Maxim Integrated Products. Typical Application Circuits continued at end of data sheet. Pin Configurations appear at end of data sheet. Selector Guide PART NO. OF DRIVERS/ RECEIVERS GUARANTEED DATA RATE (kbps) READY OUTPUT SHUTDOWN MAX3316 2/2 460 — MAX3317 2/2 460 — ✓ MAX3318 2/2 460 — ✓ MAX3319 1/1 460 ✓ AutoShutdown Plus — — — ✓ — ✓ ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX3316–MAX3319 General Description The MAX3316–MAX3319 transceivers have a proprietary low-dropout transmitter output stage enabling RS-232compatible performance from +2.25V to +3.0V with a dual-charge pump. These devices require only four 0.1µF capacitors, and are guaranteed to operate at data rates up to 460kbps. The MAX3318/MAX3319 achieve a 1µA supply current using Maxim’s revolutionary AutoShutdown Plus™ feature. These devices automatically enter a low-power shutdown mode when the RS-232 cable is disconnected or the transmitters of the connected peripherals are inactive for more than 30 seconds. They turn on again when they sense a valid transition at any transmitter or receiver input. AutoShutdown Plus saves power without changes to the existing BIOS or operating system. The MAX3318 is a 2-Tx/2-Rx device while the MAX3319 is a 1-Tx/1-Rx device. These devices also feature a logic-level output (READY) that asserts when the charge pump is regulating and the device is ready to begin transmitting. The MAX3316/MAX3317 are 2-Tx/2-Rx transceivers. The MAX3317 features a 1µA shutdown mode that can be entered by driving SHDN low. The MAX3317’s receivers remain active while in shutdown mode, allowing external devices such as modems to be monitored using only 1µA supply current. These devices are available in space-saving packages: MAX3316 (16-pin SSOP and 20-pin TSSOP), MAX3317/ MAX3318 (20-pin SSOP and 20-pin TSSOP), and MAX3319 (16-pin SSOP). MAX3316–MAX3319 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers ABSOLUTE MAXIMUM RATINGS VCC to GND ..............................................................-0.3V to +6V V+ to GND (Note 1) ..................................................-0.3V to +7V V- to GND (Note 1) ...................................................-7V to +0.3V V+ + |V-| (Note 1) .................................................................+13V Input Voltages T_IN, EN, SHDN, FORCEON, FORCEOFF to GND ..................................................-0.3V to +6V R_IN to GND .....................................................................±25V Output Voltages T_OUT to GND ...............................................................±13.2V R_OUT, INVALID, READY to GND ..........-0.3V to (VCC + 0.3V) Short-Circuit Duration, T_OUT to GND.......................Continuous Continuous Power Dissipation (TA = +70°C) 16-Pin SSOP (derate 7.14mW/°C above +70°C).........571mW 20-Pin SSOP (derate 8.00mW/°C above +70°C).........640mW 20-Pin TSSOP (derate 7.00mW/°C above +70°C).......559mW Operating Temperature Ranges MAX331_C_ _.....................................................0°C to +70°C MAX331_E_ _ ..................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Die Temperature ..............................................................+150°C Lead Temperature (soldering, 10s) .................................+300°C Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V CC = +2.25V to +3.0V, C1–C4 = 0.1µF, T A = T MIN to T MAX, unless otherwise noted. Typical values are at V CC = +2.5V, TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DC CHARACTERISTICS (VCC = +2.5V, TA = +25°C) AutoShutdown Plus Supply Current FORCEON = GND, FORCEOFF = VCC, all R_IN idle, all T_IN idle (MAX3318/MAX3319) 1 10 µA Shutdown Supply Current SHDN = GND (MAX3317), FORCEOFF = GND (MAX3318/MAX3319) 1 10 µA Supply Current SHDN = VCC, no load (MAX3317), FORCEON = FORCEOFF = VCC, no load (MAX3318/MAX3319) 0.3 1 mA LOGIC INPUTS Input Logic Threshold Low T_IN, EN, SHDN, FORCEON, FORCEOFF Input Logic Threshold High T_IN, EN, SHDN, FORCEON, FORCEOFF 0.3 ✕ VCC 0.7 ✕ VCC V 0.3 Transmitter Input Hysteresis V V T_IN, EN, SHDN, FORCEON, FORCEOFF ±0.01 ±1 µA Output Leakage Current EN = VCC (MAX3317), receivers disabled ±0.05 ±10 µA Output Voltage Low IOUT = 0.5mA Output Voltage High IOUT = -0.5mA Input Leakage Current RECEIVER OUTPUTS 0.1 ✕ VCC 0.9 ✕ VCC V V RECEIVER INPUTS -25 Input Voltage Range +25 0.3 ✕ VCC Input Threshold Low TA = +25°C Input Threshold High TA = +25°C 0.7 ✕ VCC TA = +25°C 3 5 ±3.7 ±4 Input Hysteresis Input Resistance V V V 0.3 V 7 kΩ TRANSMITTER OUTPUTS Output Voltage Swing 2 All transmitter outputs loaded with 3kΩ to ground _______________________________________________________________________________________ V 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers (V CC = +2.25V to +3.0V, C1–C4 = 0.1µF, T A = T MIN to T MAX, unless otherwise noted. Typical values are at V CC = +2.5V, TA = +25°C.) PARAMETER SYMBOL Output Resistance CONDITIONS VCC = 0, transmitter output = ±2V MIN TYP 300 10M ±25 Output Short-Circuit Current VCC = 0 or 2.25V to 3.0V, VOUT = ±12V, transmitters disabled Output Leakage Current MAX UNITS ±60 mA ±25 µA Ω AutoShutdown Plus (FORCEON = GND, FORCEOFF = VCC) (MAX3318/MAX3319) Receiver Input Threshold to INVALID Output High Figure 4a Receiver Input Threshold to INVALID Output Low Figure 4a INVALID, READY Output Voltage Low IOUT = 0.5mA INVALID, READY Output Voltage High IOUT = -0.5mA 2.7 Positive threshold Negative threshold -2.7 -0.3 0.3 0.1 ✕ VCC 0.9 ✕ VCC V V V V Receiver Positive or Negative Threshold to INVALID High tINVH Figure 4b 1 µs Receiver Positive or Negative Threshold to INVALID Low tINVL Figure 4b 30 µs Receiver or Transmitter Edge to Transmitters Enabled tWU Figure 4b (Note 2) 100 µs Receiver or Transmitter Edge to Transmitters Shutdown tAUTOSHDN VCC = 2.5V, Figure 4b (Note 2) 15 30 60 s TIMING CHARACTERISTICS (V CC = +2.25V to +3.0V, C1–C4 = 0.1µF, T A = T MIN to T MAX, unless otherwise noted. Typical values are at V CC = +2.5V, TA = +25°C.) PARAMETER SYMBOL Maximum Data Rate Receiver Propagation Delay CONDITIONS RL = 3kΩ, CL = 1000pF, one transmitter switching tPHL tPLH Receiver Output Enable Time R_IN to R_OUT, CL = 150pF MIN TYP 460 MAX UNITS kbps 0.175 0.175 µs Normal operation (MAX3317) 250 ns Normal operation (MAX3317) 250 ns Transmitter Skew |tPHL - tPLH| (Note 3) 100 ns Receiver Skew |tPHL - tPLH| 50 ns Receiver Output Disable Time _______________________________________________________________________________________ 3 MAX3316–MAX3319 ELECTRICAL CHARACTERISTICS (continued) TIMING CHARACTERISTICS (continued) (V CC = +2.25V to +3.0V, C1–C4 = 0.1µF, T A = T MIN to T MAX, unless otherwise noted. Typical values are at V CC = +2.5V, TA = +25°C.) PARAMETER SYMBOL Transition-Region Slew Rate CONDITIONS MIN VCC = 2.5V, TA = +25°C, RL = 3kΩ to 7kΩ, one transmitter switching, measured from +3V to -3V or -3V to +3V, CL = 150pF to 2500pF 4 TYP MAX UNITS 30 V/µs Note 2: A transmitter/receiver edge is defined as a transition through the transmitter/receiver input logic thresholds. Note 3: Transmitter skew is measured at the transmitter zero crosspoints. Typical Operating Characteristics (VCC = +2.5V, C1–C4 = 0.1µF, 460kbps data rate, all transmitters loaded with 3kΩ, TA = +25°C, unless otherwise noted.) MAX3316/MAX3317 TRANSMITTER OUTPUT VOLTAGE vs. SUPPLY VOLTAGE MAX3316/MAX3317 SUPPLY CURRENT vs. SUPPLY VOLTAGE 230kbps 6 4 20kbps T1 TRANSMITTING AT SPECIFIED DATA RATE T2 TRANSMITTING AT 20kbps CL = 1000pF 2.25 2.45 2.65 2.85 3.05 3.25 0 MAX3316 TOC02 -2 T_OUT- -4 -6 3.45 3.65 2.25 2.45 2.65 2.85 3.05 3.25 3.45 3.65 MAX3316/MAX3317 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE MAX3316/MAX3317 SLEW RATE vs. LOAD CAPACITANCE T_OUT+ 3 10 0 -1 FOR DATA RATES UP TO 460kbps 8 SLEW RATE (V/µs) T1 TRANSMITTING AT 460kbps T2 TRANSMITTING AT 20kbps -SLEW 6 +SLEW 4 -2 2 -3 T_OUT- -4 0 -5 0 1000 2000 LOAD CAPACITANCE (pF) 4 T1 TRANSMITTING AT 460kbps T2 TRANSMITTING AT 20kbps CL = 1000pF VCC (V) 4 1 2 VCC (V) 5 2 4 MAX3316 TOC04 0 T_OUT+ MAX3316 TOC03 2 6 TRANSMITTER OUTPUT VOLTAGE (V) 460kbps 8 SUPPLY CURRENT (mA) MAX3316 TOC01 10 TRANSMITTER OUTPUT VOLTAGE (V) MAX3316–MAX3319 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers 3000 0 1000 2000 3000 LOAD CAPACITANCE (pF) _______________________________________________________________________________________ 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers 15 20kbps 230kbps 9 20kbps 6 T1 TRANSMITTING AT SPECIFIED DATA RATE T2 TRANSMITTING AT 20kbps CL = 1000pF 3 5 0 0 0 1000 2000 LOAD CAPACITANCE (pF) 3000 2.25 MAX3318/MAX3319 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE 4 T_OUT+ 3 T1 TRANSMITTING AT 460kbps T2 TRANSMITTING AT 20kbps 1 0 -1 2.85 3.05 3.25 -5 1000 2000 LOAD CAPACITANCE (pF) 3000 MAX3316 TOC07 -2 T_OUT- -4 2.25 2.45 2.65 2.85 3.05 3.25 3.45 VCC (V) MAX3318/MAX3319 SLEW RATE vs. LOAD CAPACITANCE MAX3318/MAX3319 OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE -SLEW 6 +SLEW 4 35 3.65 T1 TRANSMITTING AT SPECIFIED DATA RATE T2 TRANSMITTING AT 20kbps 30 25 460kbps 20 230kbps 15 10 20kbps 5 FOR DATA RATES UP TO 460kbps 0 0 T1 TRANSMITTING AT 460kbps T2 TRANSMITTING AT 20kbps CL = 1000pF 0 3.65 2 T_OUT- -4 2 -6 3.45 -2 -3 T_OUT+ 4 VCC (V) 8 SLEW RATE (V/µs) 2 2.65 10 MAX3316 TOC08 TRANSMITTER OUTPUT VOLTAGE (V) 5 2.45 TRANSMITTER OUTPUT VOLTAGE (V) 230kbps MAX3316 TOC06 12 6 SUPPLY CURRENT (mA) 460kbps 10 460kbps MAX3316 TOC09 25 20 15 SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 30 T1 TRANSMITTING AT SPECIFIED DATA RATE T2 TRANSMITTING AT 20kbps MAX3316 TOC05 35 MAX3318/MAX3319 TRANSMITTER OUTPUT VOLTAGE vs. SUPPLY VOLTAGE MAX3318/MAX3319 SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX3316 TOC10 MAX3316/MAX3317 OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE 0 1000 2000 LOAD CAPACITANCE (pF) 0 3000 0 1000 2000 LOAD CAPACITANCE (pF) 3000 _______________________________________________________________________________________ 5 MAX3316–MAX3319 Typical Operating Characteristics (continued) (VCC = +2.5V, C1–C4 = 0.1µF, 460kbps data rate, all transmitters loaded with 3kΩ, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = +2.5V, C1–C4 = 0.1µF, 460kbps data rate, all transmitters loaded with 3kΩ, TA = +25°C, unless otherwise noted.) MAX3318/MAX3319 READY TURN-ON TIME vs. TEMPERATURE 300 MAX3316/MAX3317 200 MAX3318/MAX3319 100 25 20 15 10 0 0 500 1000 1500 2000 2500 120 80 0 -40 3000 160 40 5 0 200 MAX3316E TOC13 30 READY TURN-OFF TIME (ns) 400 MAX3318/MAX3319 READY TURN-OFF TIME vs. TEMPERATURE MAX3316E TOC12 T1 TRANSMITTING AT 460kbps T2 TRANSMITTING AT 20kbps READY TURN-ON TIME (µs) 500 MAX3316E TOC11 TRANSMITTER SKEW vs. LOAD CAPACITANCE (tPLH - tPHL) TRANSMITTER SKEW (ns) MAX3316–MAX3319 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers -20 0 20 40 60 80 -40 -20 0 TEMPERATURE (°C) LOAD CAPACITANCE (pF) 20 40 60 80 TEMPERATURE (°C) Pin Description PIN 6 MAX3319 SSOP FUNCTION SSOP TSSOP 1 2 2 2 2 C1+ 2 3 3 3 3 V+ +2 ✕ VCC Generated by the Charge Pump 3 4 4 4 4 C1- Negative Terminal of Voltage-Doubler ChargePump Capacitor 4 5 5 5 5 C2+ Positive Terminal of Inverting Charge-Pump Capacitor 5 6 6 6 6 C2- Negative Terminal of Inverting Charge-Pump Capacitor 6 7 7 7 7 V- 7, 14 8, 17 8, 17 8, 17 13 T_OUT 8, 13 9, 16 9, 16 9, 16 8 R_IN RS-232 Receiver Inputs 9, 12 12, 15 10, 15 10, 15 9 R_OUT CMOS Receiver Outputs 10, 11 13, 14 12, 13 12, 13 11 T_IN CMOS Transmitter Inputs 15 18 18 18 14 GND Ground 16 19 19 19 15 VCC +2.25V to +3.0V Single-Supply Voltage Receiver Enable, Active Low MAX3316 MAX3318 SSOP/ TSSOP NAME MAX3317 SSOP/ TSSOP — — 1 — — EN — 1, 10, 11, 20 11, 14 — — N.C. Positive Terminal of Voltage-Doubler ChargePump Capacitor -2 ✕ VCC Generated by the Charge Pump RS-232 Transmitter Outputs No Connection _______________________________________________________________________________________ 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers PIN NAME FUNCTION — SHDN Shutdown Control, Active Low SSOP TSSOP — — MAX3317 SSOP/ TSSOP 20 — — — 1 1 READY Ready to Transmit Output, Active High. READY is enabled high when V- goes below -2.75V and the device is ready to transmit. — — — 11 10 INVALID Valid Signal Detector Output, Active Low. A logic high indicates that a valid RS-232 level is present on a receiver input. — — — 14 12 FORCEON Force-On Input, Active High. Drive high to override AutoShutdown Plus, keeping transmitters and receivers on (FORCEOFF must be high) (Table 1). FORCEOFF Force-Off Input, Active Low. Drive low to shut down transmitters, receivers, and charge pump. This overrides AutoShutdown Plus and FORCEON (Table 1). MAX3316 — — MAX3318 SSOP/ TSSOP — MAX3319 SSOP — 20 16 Detailed Description Dual Charge-Pump Voltage Converter The MAX3316–MAX3319s’ internal power supply consists of a regulated dual charge pump that provides output voltages of +4.4V (doubling charge pump) and -4.3V (inverting charge pump), over the +2.25V to +3.0V input voltage range. The charge pump operates in discontinuous mode: if the output voltages are less than 4.4V, the charge pump is enabled; if the output voltages exceed 4.4V, the charge pump is disabled. Each charge pump requires a flying capacitor (C1, C2) and a reservoir capacitor (C3, C4) to generate the V+ and V- supplies. The READY output (MAX3318/MAX3319) is low when the charge pumps are disabled in shutdown mode. The READY signal asserts high when V- goes below -2.75V. RS-232-Compatible Transmitters The MAX3316–MAX3319s’ transmitters are inverting level translators that convert CMOS-logic levels to RS-232-compatible voltage levels. They guarantee a 460kbps data rate with worst-case loads of 3kΩ in parallel with 1000pF, providing compatibility with PC-to-PC communication software (such as LapLink™). The MAX3317’s transmitters are turned off (high impedance) when SHDN is asserted low, putting the device in shutdown mode. The MAX3318/MAX3319s’ transmitters are turned off (high impedance) when FORCEOFF is asserted low, or when the AutoShutdown Plus circuitry senses that all receiver and transmitter inputs are inactive for more than 30 seconds. The transmitter outputs can be driven to ±12V when power is off. The transmitter inputs do not have internal pullup resistors. Connect unused inputs to GND or VCC. Figure 1a shows an RS-232-compatibility circuit and Figure 1b shows MAX3316–MAX3319 transmitter output compatibility with an RS-232 receiver. RS-232 Receivers The MAX3316–MAX3319s’ receivers convert RS-232 signal levels into CMOS-logic output levels. The receivers are rated to receive signals up to ±25V. The MAX3316/MAX3318/MAX3319s’ receivers feature inverting outputs that always remain active (Table 1). The MAX3317’s receivers have inverting, three-state outputs. In shutdown, the receivers can be active or inactive (Table 2). The MAX3318/MAX3319 feature an INVALID output that is asserted low when no valid RS-232 voltage levels have been detected on all receiver inputs. Because INVALID indicates the receiver’s input condition, it is independent of the states of FORCEON and FORCEOFF. LapLink is a trademark of Traveling Software. _______________________________________________________________________________________ 7 MAX3316–MAX3319 Pin Description (continued) MAX3316–MAX3319 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers Table 1. Output Control Truth Table (MAX3318/MAX3319) OPERATION STATUS RECEIVER OR VALID RECEIVER TRANSMITTER LEVEL EDGE WITHIN 30s FORCEON FORCEOFF Shutdown (Forced Off) X 0 X Normal Operation (Forced On) 1 1 Normal Operation (AutoShutdown Plus) 0 Shutdown (AutoShutdown Plus) T_OUT R_OUT X High-Z Active X X Active Active 1 X Yes Active Active 0 1 X No High-Z Active Normal Operation INVALID* 1 Yes X Active Active Normal Operation INVALID* 1 X Yes Active Active Shutdown INVALID* 1 No No High-Z Active Normal Operation (AutoShutdown) INVALID** INVALID** Yes X Active Active Shutdown (AutoShutdown) INVALID** INVALID** No X High-Z Active X = Don’t care *INVALID connected to FORCEON MAX3318/MAX3319 AutoShutdown Plus Mode **INVALID connected to FORCEON and FORCEOFF Table 2. Shutdown and Enable Control Truth Table (MAX3317) SHDN 0 EN 0 T_OUT High-Z Active 0 1 High-Z High-Z 1 0 Active Active 1 1 Active High-Z R_OUT MAX3317 Shutdown Mode Supply current falls to less than 1µA in shutdown mode (SHDN = low). When shut down, the device’s charge pumps are turned off, V+ is pulled down to VCC, V- is pulled to ground, and the transmitter outputs are disabled (high impedance). The time required to exit shutdown is typically 30µs, as shown in Figure 2. Connect SHDN to VCC if the shutdown mode is not used; SHDN has no effect on R_OUT. 8 Maxim’s AutoShutdown Plus feature on the MAX3318/ MAX3319 allows the supply current to fall to 1µA. These devices will enter the AutoShutdown Plus mode if FORCEOFF is high, FORCEON is low, and they do not sense a valid signal transition on any receiver or transmitter input for 30 seconds. This may occur if the RS-232 cable is disconnected or if the peripheral transmitters are turned off, and the UART driving the transmitter inputs is inactive. The system turns on again when a valid transition is applied to any RS-232 receiver or transmitter input. As a result, the system saves power without changes to the existing BIOS or operating system. Figure 4a depicts valid and invalid RS-232 receiver voltage levels. INVALID indicates the receiver input’s condition and is independent of FORCEON and FORCEOFF states. Figure 3 and Table 1 summarize the operating modes of the MAX3318/MAX3319. FORCEON and FORCEOFF override AutoShutdown Plus circuitry. When neither control is asserted, the IC selects between these states automatically, based on the last receiver or transmitter edge received. _______________________________________________________________________________________ 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers MAX3316–MAX3319 +2.5V CBYPASS 0.1µF VCC C1+ C1 0.1µF C3 0.1µF C1C2+ C2 0.1µF V+ C2- MAX3316 MAX3317 MAX3318 MAX3319 V- +5V C4 0.1µF T_ OUT T_ IN RX CL 1000pF R_ IN R_ OUT TX RS-232COMPLIANT TRANSCEIVER GND Figure 1a. RS-232-Compatibility Circuit VCC OR SHDN (MAX3317) 5V/div T1 IN MAX3316–MAX3319 FORCEOFF (MAX3318/MAX3319) 2V/div T1 5V/div T1 OUT MAX3316–MAX3319 2V/div T2 RS-232-COMPLIANT RECEIVER OUTPUT 5V/div 10µs/div Figure 1b. MAX3316–MAX3319 Transmitter Output Compatibility with an RS-232 Receiver Figure 2. Transmitter Outputs when Exiting Shutdown or Powering Up _______________________________________________________________________________________ 9 When shut down, the device’s charge pumps turn off, V+ is pulled to VCC, V- is pulled to ground, the transmitter outputs are high impedance, and READY is driven low. The time required to exit shutdown is typically 30µs (Figure 2). By connecting FORCEON to INVALID, the MAX3318/ MAX3319 shut down when no valid receiver level is detected and wake up when a valid receiver level is detected. A system with AutoShutdown Plus may need time to wake up. Figure 5 shows a circuit that forces the transmitters on for 100ms, allowing enough time for the other system to realize that the MAX3318/MAX3319 is awake. If the other system outputs valid RS-232 signal transitions within that time, the RS-232 ports on both systems remain enabled. Connecting to the PC (MAX3318/MAX3319) If direct software control is desired, use INVALID to indicate DTR or ring indicator (RI) signal. This can be used to connect a hand-held device to a PC. One example is using the hot sync function on a personal digital assistant (PDA). The transmitter and receiver signals (T_OUT and R_IN) are used for communication, while INVALID causes a change of state on RI. The change of state on RI will trigger an interrupt on the PC and allow communication to begin between the device and the PC. This eliminates the need for the PC to poll constantly the receiver or transmitter lines to determine if the device is connected. Applications Information RS-232-Compatible Operation The MAX3316–MAX3319 do not meet EIA-232 requirements for transmitter output voltage levels. EIA-232 compliance specifies transmitter output voltage swings of ±5V when loaded with 3kΩ and 2500pF. The receiver inputs are fully EIA-232 compliant. The MAX3316–MAX3319 will function properly with most modern RS-232 interfaces. This allows RS-232-compatible communication in low-voltage systems without the added expense of a voltage tripler or switched-mode power supply. Capacitor Selection The capacitor type used for C1–C4 is not critical for proper operation; polarized or nonpolarized capacitors can be used. The charge pump requires 0.1µF capacitors. Increasing the capacitor values (e.g., by a factor of 10 +0.3V R_IN 30µs TIMER R -0.3V INVALID INVALID ASSERTED IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30µs. Figure 3a. INVALID Functional Diagram, INVALID Low +2.7V R_IN 30µs TIMER R -2.7V INVALID INVALID DEASSERTED IF ANY RECEIVER INPUT HAS BEEN BETWEEN +2.7V AND -2.7V FOR LESS THAN 30µs. Figure 3b. INVALID Functional Diagram, INVALID High INVALID HIGH +2.7V RECEIVER INPUT LEVELS MAX3316–MAX3319 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers INDETERMINATE +0.3V 0 INVALID LOW -0.3V INDETERMINATE -2.7V INVALID HIGH Figure 4a. Receiver Positive/Negative Thresholds for INVALID 2) reduces ripple on the transmitter outputs and slightly reduces power consumption. C2, C3, and C4 can be increased without changing C1’s value. However, do not increase C1 without also increasing the values of ______________________________________________________________________________________ 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers MAX3316–MAX3319 RECEIVER INPUTS INVALID } REGION TRANSMITTER INPUTS TRANSMITTER OUTPUTS INVALID OUTPUT VCC tINVL tINVH 0 tAUTOSHDN tAUTOSHDN tWU tWU READY *VCC OUTPUT 0 V+ VCC 0 V*MAX3318/MAX3319 Figure 4b. AutoShutdown Plus, INVALID, and READY Timing Diagram C2, C3, C4, and CBYPASS to maintain proper ratios (C1 to other capacitors). POWERMANAGEMENT UNIT MASTER SHDN LINE 0.1µF 1MΩ FORCEOFF FORCEON MAX3318 MAX3319 When using the minimum-required capacitor values, make sure the capacitor value does not degrade excessively with temperature. If in doubt, use capacitors with a higher nominal value. The capacitor’s equivalent series resistance (ESR), which usually rises at low temperatures, influences the amount of ripple on V+ and V-. Power-Supply Decoupling In most circumstances, a 0.1µF bypass capacitor is adequate. In applications that are sensitive to powersupply noise, decouple VCC to ground with a capacitor of the same value as charge pump capacitor C1. Connect bypass capacitors as close to the IC as possible. Figure 5. AutoShutdown Plus Initial Turn-On to Wake Up a Mouse or Another System Transmitter Outputs when Exiting Shutdown Figure 2 shows two transmitter outputs when exiting shutdown mode. As they become active, the two transmitter outputs are shown going to opposite RS-232compatible levels (one transmitter input is high, the other is low). Each transmitter is loaded with 3kΩ in par- ______________________________________________________________________________________ 11 MAX3316–MAX3319 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers allel with 2500pF. The transmitter outputs display no ringing or undesirable transients as they come out of shutdown. Note that the transmitters are enabled only when the magnitude of V- exceeds approximately -3V. 2V/div T1 IN High Data Rates The MAX3316–MAX3319 maintain RS-232-compatible ±3.7V minimum transmitter output voltage even at high data rates. Figure 6 shows a transmitter loopback test circuit. Figure 7 shows a loopback test result at 230kbps. For Figure 7, all transmitters were driven simultaneously at 230kbps into EIA/TIA-562 loads in parallel with 1000pF. 5V/div T1 OUT R1 OUT 2V/div Figure 7. Loopback Test Result at 230kbps VCC CBYPASS Ordering Information (continued) VCC PART C1+ C1 C1C2+ C2 V+ C3* MAX3316 MAX3317 MAX3318 MAX3319 VC4 C2- T_ OUT T_ IN R_ IN R_ OUT 5k FORCEON** TEMP. RANGE PIN-PACKAGE MAX3317CUP 0°C to +70°C 20 TSSOP MAX3317CAP 0°C to +70°C 20 SSOP MAX3317EUP -40°C to +85°C 20 TSSOP MAX3317EAP -40°C to +85°C 20 SSOP MAX3318CUP 0°C to +70°C 20 TSSOP MAX3318CAP 0°C to +70°C 20 SSOP MAX3318EUP -40°C to +85°C 20 TSSOP MAX3318EAP -40°C to +85°C 20 SSOP MAX3319CAE 0°C to +70°C 16 SSOP MAX3319EAE -40°C to +85°C 16 SSOP CL 1000pF Chip Information VCC FORCEOFF** GND TRANSISTOR COUNT: 1130 PROCESS: CMOS *C3 CAN BE RETURNED TO VCC OR GND. **MAX3318/MAX3319 Figure 6. Loopback Test Circuit 12 ______________________________________________________________________________________ 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers TOP VIEW READY 1 C1+ 1 20 FORCEOFF C1+ 2 19 VCC V+ 3 18 GND C1- 3 17 T1OUT C2+ 4 C1- 4 C2+ 5 MAX3318 V+ 2 14 FORCEON T2OUT 8 13 T1IN R2IN 9 12 T2IN R2OUT 10 20 N.C. 15 GND C1+ 2 19 VCC V+ 3 18 GND 13 R1IN C1- 4 17 T1OUT MAX3316 12 R1OUT C2+ 5 V- 6 11 T1IN C2- 6 T2OUT 7 10 T2IN V- 7 14 T1IN T2OUT 8 13 T2IN 15 R1OUT V- 7 N.C. 1 14 T1OUT MAX3316 C2- 5 16 R1IN C2- 6 16 VCC R2IN 8 9 R2OUT SSOP 11 INVALID 16 R1IN 15 R1OUT R2IN 9 12 R2OUT N.C. 10 11 N.C. TSSOP SSOP/TSSOP EN 1 20 SHDN READY 1 C1+ 2 19 VCC C1+ 2 V+ 3 18 GND V+ 3 C1- 4 C2+ 5 MAX3317 C2- 6 16 FORCEOFF 15 VCC 14 GND MAX3319 17 T1OUT C1- 4 16 R1IN C2+ 5 12 FORCEON 15 R1OUT C2- 6 11 T1IN V- 7 14 N.C. V- 7 T2OUT 8 13 T1IN R1IN 8 R2IN 9 12 T2IN R2OUT 10 11 N.C. 13 T1OUT 10 INVALID 9 R1OUT SSOP SSOP/TSSOP ______________________________________________________________________________________ 13 MAX3316–MAX3319 Pin Configurations (continued) 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers MAX3316–MAX3319 Typical Application Circuits (continued) +2.5V +2.5V 19 0.1µF C1 0.1µF 2 C1+ 4 5 C2 0.1µF 6 V+ 3 C3* 0.1µF C1- MAX3317 C2+ V- 0.1µF T1OUT 17 T2OUT 8 12 T2IN CMOS OUTPUTS 5k 10 R2OUT R2IN 9 3 5 VCC V+ C2+ MAX3316 GND 18 SHDN V- 6 CMOS INPUTS T2OUT 7 10 T2IN RS-232COMPATIBLE OUTPUTS R1IN 13 CMOS OUTPUTS 5k 9 R2OUT R2IN 8 5k 20 *C3 CAN BE RETURNED TO EITHER VCC OR GROUND. C4 0.1µF T1OUT 14 5k EN C3* 0.1µF C2- 12 R1OUT RS-232COMPATIBLE INPUTS 2 C1- 11 T1IN RS-232COMPATIBLE OUTPUTS R1IN 16 15 R1OUT 14 0.1µF 4 C4 0.1µF CMOS INPUTS 1 1 C1+ 7 C2- 13 T1IN 16 0.1µF VCC GND 15 CIRCUIT SHOWN IS FOR THE 16-PIN SSOP. ______________________________________________________________________________________ RS-232COMPATIBLE INPUTS 2.5V, 1µA, 460kbps, RS-232-Compatible Transceivers +2.5V CBYPASS C1 0.1µF 2 C1+ 4 5 C2 0.1µF CMOS INPUTS 19 0.1µF 6 C1- VCC 3 V+ MAX3318 C2+ V- C3 0.1µF 7 C2- 13 T1IN T1OUT 17 12 T2IN T2OUT 8 C4 0.1µF RS-232-COMPATIBLE OUTPUTS R1IN 16 15 R1OUT CMOS OUTPUTS RS-232-COMPATIBLE INPUTS 5k R2IN 9 10 R2OUT 5k 1 14 READY AutoShutdown Plus INVALID 11 FORCEOFF 20 FORCEON GND TO POWERMANAGEMENT UNIT VCC 18 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________15 © 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX3316–MAX3319 Typical Application Circuits (continued)