LTC2801/LTC2802/ LTC2803/LTC2804 1.8V to 5.5V RS-232 Single and Dual Transceivers Features Description 1.8V to 5.5V Supply Voltage n Single and Dual Transceivers n High-Speed Operation 1Mbps for 250pF/3kΩ Load (LTC2802, LTC2804) 250kbps for 1nF/3kΩ Load 100kbps for 2.5nF/3kΩ TIA/EIA-232-F Load n Low-Power 1µA Shutdown and 15µA ReceiversActive Modes n No Damage or Latchup to ±10kV ESD on RS-232 Interface n Logic Supply Pin for Easy Level-Shifting to UART or Microprocessor n Low-Latency Output Enable Allows Line Sharing and Half-Duplex Operation n True RS-232 Compliant Output Levels n Small Footprint: LTC2801/LTC2802 4mm × 3mm DFN Package LTC2803/LTC2804 Narrow SSOP-16 and 5mm × 3mm DFN Packages The LTC®2801/LTC2802/LTC2803/LTC2804 are single and dual RS-232 transceivers in narrow SSOP and chip-scale DFN packages. All operate over a supply range of 1.8V to 5.5V, which permits operation directly from two alkaline, NiCd or NiMH cells. An integrated DC-to-DC converter generates power supplies for driving RS-232 levels. A logic supply pin allows easy interfacing with different logic levels independent of the DC-DC supply. LTC2801 1+1 Applications LTC2802 1+1 n Battery-Powered Systems n Computers and Consumer Electronics n Diagnostic Ports n L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. These parts are compatible with the TIA/EIA-232-F standard. Driver outputs are protected from overload and can be shorted to ground or up to ±15V without damage. To extend battery life, receivers can be kept active, operating at reduced speed, with only 15µA current. In shutdown mode, current is further reduced to 1µA. Product Selection Guide PART NUMBER DRIVERS AND MAXIMUM RECEIVERS DATA RATE MODES* PACKAGE 0.25Mbps SD, RA, DD, AO 1Mbps DFN-12 SD, RA, DD, AO DFN-12 LTC2803 2+2 0.25Mbps SD, RA, DD, AO DFN-16 LTC2803-1 2+2 0.25Mbps SD, AO SSOP-16 LTC2804 2+2 1Mbps SD, RA, DD, AO DFN-16 LTC2804-1 2+2 1Mbps SD, AO SSOP-16 *SD = Shutdown, RA = Receiver Active (low power), DD = Drivers Disabled, AO = All On Typical Application 1.8V TO 5.5V C4 1µF LTC2802 at 1.8V and 1Mbps L1 10µH SW VCC VL LTC2802 MODE TIN 5V/DIV TOUT TOUT TIN RIN ROUT GND 2V/DIV CAP PS OFF ON C1 220nF 2V/DIV VEE VDD C2 1µF C3 1µF ROUT VCC = VL = 1.8V 400ns/DIV WRAPPING DATA TOUT LOAD = 250pF + RIN ROUT LOAD = 150pF 2801 TA01b 2801 TA01a 2801234fe LTC2801/LTC2802/ LTC2803/LTC2804 Absolute Maximum Ratings (Note 1) PS, ON/OFF......................................–0.3V to (VL + 0.3V) RIN, R1IN, R2IN...........................................–25V to 25V TOUT, T1OUT, T2OUT.................................. –15V to 15V ROUT, R1OUT, R2OUT.....................–0.3V to (VL + 0.3V) Operating Temperature LTC280XC.................................................0°C to 70°C LTC280XI..............................................–40°C to 85°C Storage Temperature Range...................–65°C to 125°C Lead Temperature (Soldering, 10 sec) GN Package....................................................... 300°C Input Supplies VCC...........................................................–0.3V to 7V VL.......................................................... –0.3V to 6.7V Generated Supplies VDD..................................................VCC –0.3V to 7.5V VEE. ....................................................... 0.3V to –7.5V VDD – VEE..............................................................14V SW................................................... –0.3V to VDD + 0.3V CAP................................................... +0.3V to VEE – 0.3V TIN, T1IN, T2IN, MODE.................................–0.3V to 7V Pin Configuration LTC2801, LTC2802 1-Driver/1-Receiver LTC2803, LTC2804 2-Driver/2-Receiver LTC2803-1, LTC2804-1 2-Driver/2-Receiver TOP VIEW TOP VIEW TOP VIEW R1IN 1 16 R1OUT R1IN 1 16 R1OUT R2IN 2 15 R2OUT R2IN 2 15 R2OUT RIN 1 12 ROUT TOUT 2 11 TIN T1OUT 3 14 T1IN T1OUT 3 14 T1IN VCC 3 10 VL T2OUT 4 13 T2IN T2OUT 4 13 T2IN VDD 4 VCC 5 12 VL SW 5 VDD 6 11 ON/OFF GND 6 SW 7 10 CAP GND 8 9 13 VEE 17 9 MODE VCC 5 8 PS VDD 6 11 MODE 7 CAP SW 7 10 PS GND 8 DE PACKAGE 12-LEAD (4mm s 3mm) PLASTIC DFN TJMAX = 125°C, θJA = 43°C/W, θJC = 4.3°C/W (4 Layer) EXPOSED PAD (PIN 13) IS VEE, MUST BE SOLDERED TO PCB VEE 12 VL 9 CAP DHC PACKAGE 16-LEAD (5mm s 3mm) PLASTIC DFN TJMAX = 125°C, θJA = 44°C/W, θJC = 4.3°C/W (4 Layer) EXPOSED PAD (PIN 17) IS VEE, MUST BE SOLDERED TO PCB VEE GN PACKAGE 16-LEAD (NARROW 0.150) PLASTIC SSOP TJMAX = 125°C, θJA = 110°C/W, θJC = 40°C/W (4 Layer) Order Information LEAD FREE FINISH LTC2801CDE#PBF TAPE AND REEL LTC2801CDE#TRPBF PART MARKING* 2801 PACKAGE DESCRIPTION 12-Lead (4mm × 3mm) Plastic DFN TEMPERATURE RANGE 0°C to 70°C LTC2801IDE#PBF LTC2801IDE#TRPBF 2801 12-Lead (4mm × 3mm) Plastic DFN –40°C to 85°C LTC2802CDE#PBF LTC2802CDE#TRPBF 2802 12-Lead (4mm × 3mm) Plastic DFN 0°C to 70°C LTC2802IDE#PBF LTC2802IDE#TRPBF 2802 12-Lead (4mm × 3mm) Plastic DFN –40°C to 85°C LTC2803CDHC#PBF LTC2803CDHC#TRPBF 2803 16-Lead (5mm × 3mm) Plastic DFN 0°C to 70°C LTC2803IDHC#PBF LTC2803IDHC#TRPBF 2803 16-Lead (5mm × 3mm) Plastic DFN –40°C to 85°C LTC2804CDHC#PBF LTC2804CDHC#TRPBF 2804 16-Lead (5mm × 3mm) Plastic DFN 0°C to 70°C LTC2804IDHC#PBF LTC2804IDHC#TRPBF 2804 –40°C to 85°C 16-Lead (5mm × 3mm) Plastic DFN LTC2803CGN-1#PBF LTC2803CGN-1#TRPBF 28031 16-Lead (Narrow 0.150) Plastic SSOP 0°C to 70°C LTC2803IGN-1#PBF LTC2803IGN-1#TRPBF 2803I1 16-Lead (Narrow 0.150) Plastic SSOP –40°C to 85°C LTC2804CGN-1#PBF LTC2804CGN-1#TRPBF 28041 16-Lead (Narrow 0.150) Plastic SSOP 0°C to 70°C LTC2804IGN-1#PBF LTC2804IGN-1#TRPBF 2804I1 16-Lead (Narrow 0.150) Plastic SSOP –40°C to 85°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ 2801234fe LTC2801/LTC2802/ LTC2803/LTC2804 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VCC = 1.8V to 5.5V, VL = 1.8V to 5.5V, Normal Mode. Typical values are given for VCC = VL = 3.3V and TA = 25°C, unless otherwise noted. SYMBOL PARAMETER CONDITIONS VCC Supply Current Outputs Unloaded Normal Mode (Note 3) Receivers Active Mode Shutdown Mode MIN TYP MAX UNITS l l 2.3 1 1 10 10 mA µA µA Outputs Unloaded Normal Mode (LTC2801, LTC2802) Normal Mode (LTC2803, LTC2804) Receivers Active Mode Shutdown Mode l l l l 0.08 0.15 15 1 0.15 0.30 30 10 mA mA µA µA Power Supplies ICC IL VL Supply Current Driver VOLD Output Voltage RL = 3kΩ Low l –5 –5.7 V RL = 3kΩ High l 5 6.2 V 0.6 V VOHD Output Voltage VHYSD Logic Input Hysteresis IOSD Output Short Circuit Current VL = VCC = 5.5V; VTOUT = 0V l ±35 ±70 mA IPOLD Power-Off Output Leakage Current VL = VCC = VDD = VEE = 0V; VTOUT = ±2V l ±0.1 ±10 µA IOLD Output Leakage Current l Shutdown or Receivers Active or Drivers Disabled Modes, –15V ≤ VTOUT ≤ 15V ±0.1 ±10 µA VIR Input Thresholds Receivers Active Mode l 0.8 1.5 2.4 V VILR Input Thresholds Normal Mode, Input Low l 0.8 1.3 VIHR Input Thresholds Normal Mode, Input High l VHYSR Input Hysteresis Normal Mode l Receiver V 1.7 2.5 V 0.1 0.4 1.0 V 0.2 0.4 V VOLR Output Voltage Output Low, IROUT = 1mA (Sinking) l VOHR Output Voltage Output High, IROUT = –1mA (Sourcing) l VL –0.4 VL –0.2 RIN Input Resistance –15V ≤ VRIN ≤ 15V l 3 5 7 kW IOSR Output Short Circuit Current VL = 5.5V; 0V ≤ VROUT ≤ VL l ±25 ±50 mA V Logic IIN Logic Input Voltage Threshold l Logic Input Current l 0.4 0.67 • VL V ±1 µA Power Supply Generator VDD Regulated VDD Output Voltage Driver RL = 3kW (Note 3) LTC2801, LTC2802: VTIN = VL LTC2803, LTC2804: VT1IN = VL , VT2IN = 0V 7 V VEE Regulated VEE Output Voltage Driver RL = 3kW (Note 3) LTC2801, LTC2802: VTIN = VL LTC2803, LTC2804: VT1IN = VL , VT2IN = 0V – 6.3 V 2801234fe LTC2801/LTC2802/ LTC2803/LTC2804 Switching Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VCC = 1.8V to 5.5V, VL = 1.8V to 5.5V, Normal Mode. Typical values are given for VCC = VL = 3.3V and TA = 25°C, unless otherwise noted. SYMBOL PARAMETER CONDITIONS Maximum Data Rate LTC2801, LTC2803 (Note 3) RL = 3kW, CL = 2.5nF RL = 3kW, CL = 1nF MIN TYP MAX UNITS l l 100 250 kbps kbps LTC2802, LTC2804 (Note 3) RL = 3kW, CL = 2.5nF RL = 3kW, CL = 1nF RL = 3kW, CL = 250pF l l l 100 250 1000 kbps kbps kbps LTC2801, LTC2803 (Figure 1) VCC = VL = 1.8V, RL = 3kW, CL = 2.5nF VCC = VL = 5.5V, RL = 3kW, CL = 50pF l l 4 LTC2802, LTC2804 (Figure 1) VCC = VL = 1.8V, RL = 3kW, CL = 2.5nF VCC = VL = 5.5V, RL = 3kW, CL = 50pF l l 4 RL = 3kW, CL = 50pF (Figure 2) LTC2801, LTC2803 LTC2802, LTC2804 l l Driver SR(D) tPHLD, tPLHD Driver Slew Rate Driver Propagation Delay 1 0.2 30 V/µs V/µs 150 V/µs V/µs 2 0.5 µs µs tSKEWD Driver Skew RL = 3kW, CL = 50pF (Figure 2) LTC2801, LTC2803 LTC2802, LTC2804 tPZHD, tPZLD Driver Output Enable Time PS = VL, MODE = ↑, RL = 3kW, CL = 50pF (Figure 4) l 0.6 2 µs tPHZD, tPLZD Driver Output Disable Time PS = VL, MODE = ↓, RL = 3kW, CL = 50pF (Figure 4) l 0.3 2 µs tPHLR, tPLHR Receiver Propagation Delay CL = 150pF (Figure 3) l 0.2 0.4 µs tSKEWR Receiver Skew CL = 150pF (Figure 3) tRR, tFR Receiver Rise or Fall Time CL = 150pF (Figure 3) l 60 200 ns tPZHR, tPZLR Shutdown to Receiver Output Enable PS = MODE = ↑ or ON/OFF = ↑, RL = 1kW, CL = 150pF (Figure 5) l 5 15 µs tPHZR, tPLZR Receiver Output Disable upon Shutdown PS = MODE = ↓ or ON/OFF = ↓, RL = 1kW, CL = 150pF (Figure 5) l 0.15 0.3 µs (Notes 3 and 4) l 0.2 2 ms 100 50 ns ns Receiver 50 ns Power Supply Generator VDD/VEE Supply Rise Time Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: All currents into pins are positive; all voltages are referenced to GND unless otherwise specified. Note 3: Guaranteed by other measured parameters and not tested directly. Note 4: Time from PS ↑ or ON/OFF ↑ until VDD ≥ 5V and VEE ≤ –5V. 2801234fe LTC2801/LTC2802/ LTC2803/LTC2804 Test Circuits TOUT RL TIN VL TIN CL tTHL 3V –3V TOUT SR(D) = TIN tr, tf ≤ 40ns tTLH 6V 3V –3V 0V VOHD VOLD 2801 F01 tTHL or tTLH Figure 1. Driver Slew Rate Measurement TOUT TIN RL TIN 1/2 VL CL VL 1/2 VL tPHLD 0V TOUT 0V tPLHD 0V tSKEWD = |tPHLD – tPLHD| VOHD VOLD 2801 F02 TIN tr, tf ≤ 40ns Figure 2. Driver Timing Measurement ROUT RIN 1.5V CL RIN 3V 1.5V tPHLR ROUT –3V tPLHR 1/2 VL 1/2 VL tSKEWR = |tPHLR – tPLHR| VOHR VOLR 2801 F03 RIN tr, tf ≤ 40ns Figure 3. Receiver Timing Measurement MODE 0 OR VL TOUT MODE RL 1/2 VL VL 1/2 VL tPZHD 5V TOUT 0V tPHZD VOHD – 0.5V VOHD 0V CL tPZLD TOUT tPLZD –5V 0V VOLD + 0.5V VOLD 2801 F04 MODE tr, tf ≤ 40ns Figure 4. Driver Enable/Disable Times 2801234fe LTC2801/LTC2802/ LTC2803/LTC2804 Test Circuits GND VL PS AND MODE RL –3V OR 3V VL 1/2 VL tPZHR ROUT PS AND MODE 1/2 VL ROUT tPHZR 1/2 VL CL V VOHR – 0.5V OHR 0V tPZLR ROUT 0V tPLZR 1/2 VL VL VOLR + 0.5V VOLR 2801 F05 PS AND MODE tr, tf ≤ 40ns Figure 5. Receiver Enable/Disable Times Typical Performance Characteristics LTC2803 at 1.8V and 250kbps TA = 25°C, VCC = VL = 3.3V unless otherwise noted. Drivers Disabled Mode Supply Current vs Supply Voltage LTC2804 at 1.8V and 1Mbps 3.0 T1IN 2.5 2V/DIV T1OUT T1OUT T2OUT T2OUT 10V/DIV R1OUT VCC = VL = 1.8V 2µs/DIV WRAPPING DATA TOUT LOAD = 1nF + RIN ROUT LOAD = 150pF 2801 G01 125kbps 20.8kbps LTC2804 LTC2803 1 2 3 4 5 SUPPLY VOLTAGE (V) 6 2801 G04 250kbps 1nF 250pF 600 400 DATA RATE (kbps) 800 125kbps 60 40 20.8kbps 20 LTC2804 LTC2802 200 6 2801 G03 80 40 0 5 3 4 SUPPLY VOLTAGE (V) 100 250pF 0 2 Supply Current vs Load Capacitance (Dual Transceiver) 60 20 10 0 1nF 1 2801 G02 ALL DRIVERS SWITCHING VCC = VL = 1.8V RL = 3k 80 SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 100 40 20 0 Supply Current vs Data Rate ALL DRIVERS SWITCHING VCC = VL RL = 3k 250kbps CL = 1nF 50 0.5 VCC = VL = 1.8V 400ns/DIV WRAPPING DATA TOUT LOAD = 250pF + RIN ROUT LOAD = 150pF Supply Current vs Supply Voltage (Dual Transceiver) 60 1.0 R2OUT 2V/DIV TA = –40°C 1.5 R1OUT R2OUT 2V/DIV TA = 25°C 2.0 SUPPLY CURRENT (mA) 10V/DIV 30 SUPPLY CURRENT (mA) 2V/DIV VCC = VL TA = 85°C T1IN 1000 2801 G05 0 VCC = VL = 1.8V LTC2804 RL = 3k LTC2803 ALL DRIVERS SWITCHING 1 3 2 4 LOAD CAPACITANCE (nF) 5 2801 G06 2801234fe LTC2801/LTC2802/ LTC2803/LTC2804 Typical Performance Characteristics Receiver Output Voltage vs Load Current Receiver Input Threshold vs Temperature VL = 5.5V VL = 3.3V VL = 1.8V 2.5 2.0 1.5 INPUT LOW 1.0 0.5 Receiver Output Duty Cycle 4 3 2 1 50 25 75 0 TEMPERATURE (°C) 100 0 125 0 1 2 3 4 5 6 LOAD CURRENT (mA) Driver Slew Rate vs Load Capacitance SLEW RATE (V/µs) 60 SHORT-CIRCUIT CURRENT (mA) 70 50 40 30 20 10 0 1 2 4 3 LOAD CAPACITANCE (nF) 5 THRESHOLD VOLTAGE (V) 20 50 10–7 40 30 SINKING VL = 5.5V VL = 3.3V VL = 1.8V 10 100 1000 DATA RATE (kbps) SOURCING 20 V(TOUT) = 15V OR V(TOUT) = –15V 10–9 10–10 10 REGULATOR CAN LIMIT FURTHER 0 50 –50 –25 25 75 0 TEMPERATURE (°C) 100 125 10–11 –50 –25 50 25 75 0 TEMPERATURE (°C) 125 LTC2804 Driver Outputs Enable/Disable 2V/DIV MODE AND PS 100 2801 G12 2801 G11 2V/DIV 10000 Shutdown or Drivers Disabled Mode Driver Leakage vs Temperature 10–8 LTC2804 Driver Outputs Exiting Shutdown TA = 85°C TA = 25°C TA = –40°C INPUT HIGH NORMAL MODE 40 10–6 Logic Input Threshold vs VL Supply Voltage 2.5 60 60 2801 G10 3.0 RECEIVERS ALIVE MODE 2801 GO9 Driver Short-Circuit Current vs Temperature FALLING (LTC2802/04) RISING (LTC2802/04) FALLING (LTC2801/03) RISING (LTC2801/03) 80 0 8 RIN = ±3V CL = 150pF 2801 GO8 2801 GO7 80 7 LEAKAGE CURRENT (A) 0 –50 –25 0 100 VL = 5.5V VL = 3.3V VL = 1.8V 5 INPUT HIGH OUTPUT VOLTAGE (V) THRESHOLD VOLTAGE (V) 6 POSITIVE DUTY CYCLE (%) 3.0 TA = 25°C, VCC = VL = 3.3V unless otherwise noted. MODE 2.0 1.5 T1OUT 5V/DIV 1.0 INPUT LOW T1OUT 5V/DIV T2OUT T2OUT 0.5 0 1 2 3 4 5 VL SUPPLY VOLTAGE (V) 6 2801 G13 100µs/DIV VCC = 3.3V VL = 1.8V LOAD = 3k + 2.5nF 2µs/DIV VCC = 3.3V VL = 1.8V LOAD = 3k + 250pF 2801 G14 2801 G15 2801234fe LTC2801/LTC2802/ LTC2803/LTC2804 Pin Functions PIN NUMBER 2801 2802 2803 2804 VCC 3 5 5 Input Supply (1.8V-5.5V). Bypass to GND with a 1µF capacitor. VDD 4 6 6 Generated Positive Supply Voltage for RS-232 Driver (7V). Connect a 1µF capacitor between VDD and GND. VEE 13* 17* 9 Generated Negative Supply Voltage for RS-232 Driver (–6.3V). Connect a 1µF capacitor between VEE and GND. SW 5 7 7 Switch Pin. Connect a 10µH inductor between SW and VCC. GND 6 8 8 Ground. CAP 7 9 10 Charge Pump Capacitor for Generated Negative Supply Voltage. Connect a 220nF capacitor between CAP and SW. VL 10 12 12 Logic Supply (1.8V-5.5V) for the receiver outputs, driver inputs, and control inputs. This pin should be bypassed to GND with a 220nF capacitor if it’s not tied to VCC. TIN (T1IN, T2IN) 11 14, 13 14, 13 TOUT (T1OUT, T2OUT) 2 3, 4 3, 4 PIN NAME 2803-1 2804-1 COMMENTS Driver Input(s), referenced to VL. RS-232 Driver Output(s). RIN (R1IN, R2IN) 1 1, 2 1, 2 ROUT (R1OUT, R2OUT) 12 16, 15 16, 15 RS-232 Receiver Input(s). Includes internal 5kΩ termination resistor(s). PS 8 10 — Power Supply control pin, referenced to VL. Enables the integrated DC-DC converter. MODE 9 11 — Mode control pin, referenced to VL. See Table 1 for functionality. ON/OFF — — 11 Transceiver enable pin, referenced to VL. A logic low puts the device in Shutdown mode and places both driver and receiver outputs in a high impedance state. Receiver Output(s), referenced to VL. Output is short-circuit protected to GND/VCC/VL, and is high impedance in Shutdown mode, allowing data line sharing. *Backside thermal pad Mode Control Table 1. LTC2801, LTC2802, LTC2803, LTC2804 MODE NAME PS MODE RECEIVER OUTPUT(S) DC-DC DRIVER OUTPUT(S) IVCC* IVL* SHUTDOWN L L HI-Z OFF HI-Z 1µA 1µA RECEIVER(S) ACTIVE L H ON OFF HI-Z 1µA 15µA DRIVER(S) DISABLED H L ON ON HI-Z 2.1mA 80µA OR 150µA NORMAL H H ON ON ON 2.3mA 80µA OR 150µA Table 2. LTC2803-1, LTC2804-1 MODE NAME ON/OFF RECEIVER OUTPUTS DC-DC DRIVER OUTPUTS IVCC* IVL* SHUTDOWN L HI-Z OFF HI-Z 1µA 1µA NORMAL H ON ON ON 2.3mA 150µA *Typical currents for static drivers. Normal mode currents are for unloaded outputs. 2801234fe LTC2801/LTC2802/ LTC2803/LTC2804 Feature Summary FEATURE 2801 2802 2803 2803-1 2804 2804-1 DRIVERS and RECEIVERS 1+1 1+1 2+2 2+2 2+2 2+2 DFN-12 DFN-12 DFN-16 SSOP-16 DFN-16 SSOP-16 l l l l l l PACKAGE 1.8V - 5.5V OPERATION 1.8V - 5.5V LOGIC SUPPLY (VL) l l l l l l SHUTDOWN (1µA) l l l l l l RECEIVER(S) ACTIVE (15µA) l l l DRIVER(S) DISABLE l l l 100kb/s for RL = 3kΩ, CL = 2.5nF l l l l l l 250kb/s for RL = 3kΩ, CL = 1nF l l l l l l l l 1Mb/s for RL = 3kΩ, CL = 250pF l l l Block Diagram L1 10µH C1 220nF 1.8V TO 5.5V C4 1µF VCC SW CAP VDD VEE VL 1.8V TO 5.5V BOOST REGULATOR C5 220nF VL ** C3 1µF C2 1µF VDD T2IN T2OUT T1IN T1OUT ** VL ** R2OUT GND VEE R2IN ** 5k R1IN R1OUT VL LTC2801 LTC2802 LTC2803 LTC2804 LTC2803-1 LTC2804-1 PS MODE 5k ** GND CONTROL ON/OFF LTC2803 LTC2804 LTC2803-1 LTC2804-1 2801 BD GND 2801234fe LTC2801/LTC2802/ LTC2803/LTC2804 Applications Information Overview The LTC2801 family of RS-232 transceivers operates on a VCC supply of 1.8V to 5.5V, utilizing a switching regulator to generate the necessary higher voltage rails for the drivers. The transceivers interface with logic operating on any supply from 1.8V to 5.5V, independent of the VCC voltage. Depending on the device, one or two control pins are available to invoke Shutdown, Receiver Active and Driver Disable features. The on-chip DC-DC converter operates from the VCC input, generating a 7V VDD supply and a charge pumped – 6.3V VEE supply, as shown in Figure 6. VDD and VEE power the output stage of the drivers and are regulated to levels that guarantee greater than ±5V output swing. The DC-DC converter requires a 10µH inductor (L1) and a bypass capacitor (C4) of at least 1µF. The recommended size for the charge pump capacitor (C1) is 220nF and for the storage capacitors (C2 and C3) is 1µF. Larger storage capacitors up to 4.7µF may be used if C1 is kept at 20% to 50% their size and C4 is also scaled. Locate C1-C4 close to their associated pins. L1 10µH VCC C1 220nF SW C2 1µF VL C5* 220nF VCC VL EXTERNAL DEVICE RS-232 2801 F07 BOOST REGULATOR *OMIT IF VL IS CONNECTED TO VCC Power-Saving Modes When the DC-DC converter and drivers are turned off (PS and MODE or ON/OFF = logic low), VCC supply current is reduced to 1µA. Tables 1 and 2 summarize the modes for each device. In Shutdown mode, VL supply current is reduced to 1µA, and both receiver and driver outputs assume a high impedance state. In Receivers Active mode, the quiescent VL supply current is reduced to 15µA and the driver outputs assume a high impedance state. The receivers operate at a reduced rate (typically 100 kbps) with hysteresis turned off. Half-Duplex Operation CAP VDD 1.8V TO 5.5V ANY VOLTAGE FROM 1.8V TO 5.5V Figure 7. VCC and VL Are Independent DC-DC Converter 1.8V TO 5.5V C4 1µF ANY VOLTAGE FROM 1.8V TO 5.5V VEE 2801 F06 C3 1µF Figure 6. DC/DC Converter and Recommended Bypassing VL Logic Supply A separate logic supply pin VL allows the LTC2801 family to interface with any logic signal from 1.8V to 5.5V, as shown in Figure 7. Simply connect the desired logic supply to VL. There is no interdependency between VCC and VL; they may simultaneously operate at any voltage from 1.8V to 5.5V and sequence in any order. If VL is powered separately from VCC , bypass VL with a 220nF capacitor (C5). When the DC-DC converter is kept on (PS = logic high), MODE serves as a low-latency driver enable for half-duplex operation. Each driver is enabled and disabled in less than 2µs, while each receiver remains continuously active. This mode of operation is illustrated in Figures 15-17. Battery Operation To maximize battery life, connect VCC (and L1) directly to the unregulated battery voltage and VL to the regulated supply, as shown in Figure 22. This configuration typically minimizes conversion loss while providing compatibility with system logic levels. Inductor Selection A 10µH inductor with a saturation current (ISAT) rating of at least 200mA and low DCR (copper wire resistance) is recommended. Some small inductors meeting these requirements are listed in Table 3. 2801234fe 10 LTC2801/LTC2802/ LTC2803/LTC2804 Applications Information Table 3. Recommended Inductors PART NUMBER ISAT MAX DCR (mA) (Ω) SIZE (mm) MANUFACTURER LQH2MCN100K02L 225 1.2 2 × 1.6 × 0.95 Murata www.murata.com LBC2016T100K 245 0.85 2 × 1.6 × 1.6 Taiyo Yuden www.t-yuden.com FSLB2520-100K 220 1.1 2.5 × 2 × 1.6 Toko www.tokoam.com Capacitor Selection flowing through inductor L1 and capacitors C1, C2. The peak inrush current must not exceed 2A. To avoid this condition, add a 1Ω resistor as shown in Figure 8. This precaution is not relevant for supply voltages below 4.5V or rise times longer than 10µs. Board Layout The board layout should minimize the length and area of the SW and CAP traces. Suggested compact layouts for the LTC2801 family are shown in Figure 9 (a) and (b). The small size of ceramic capacitors makes them ideal for the LTC2801 family. X5R and X7R (preferred) types are recommended because their ESR is low and they retain their capacitance over relatively wide voltage and temperature ranges. Use a voltage rating of at least 10V. C1 GND C2 Table 4. Recommended Ceramic Capacitor Manufacturers GND MANUFACTURER URL Murata www.murata.com TDK www.tdk.com Taiyo Yuden www.t-yuden.com AVX www.avxcorp.com Kemet www.kemet.com GND C5 L1 VL VCC GND C4 GND TOP VIEW C3 = VIA Inrush Current and Supply Overshoot Precaution In certain applications, such as battery-operated and wall-adapter devices, fast supply slew rates are generated when power is connected. If VCC’s voltage is greater than 4.5V and its rise time is faster than 10µs, the pins VDD and SW can exceed their ABS MAX values during startup. When supply voltage is applied to VCC , the voltage difference between VCC and VDD generates inrush current L1 10µH 4.5V TO 5.5V R1 1Ω 1/8W INRUSH CURRENT C1 GND C2 GND C5 VCC GND C4 CAP GND VCC C2 1µF L1 VL C1 220nF SW C4 1µF GND C3 VDD GND TOP VIEW = VIA SCALE R1 WITH C1, C2, 1/C4 2801 F08 Figure 8. Supply Overshoot Protection for Input Supplies of 4.5V or Higher 2801 F09 Figure 9. Recommended Board Layouts for (a) Single and (b) Dual Transceiver Parts 2801234fe 11 LTC2801/LTC2802/ LTC2803/LTC2804 Typical Applications 1.8V TO 5.5V 5 12 LTC2803 VL 11 RA ON 5 VCC VCC 1.8V TO 5.5V CELL PHONE MODE 10 LTC2804 12 VL 11 MODE VBATT PS 13 T2IN T2OUT 4 14 T1IN T1OUT 3 15 R2OUT R2IN 2 16 R1OUT R1IN 1 10 PS RTS TD CTS RD T2OUT 4 14 T1IN T1OUT 3 15 R2OUT R2IN 2 16 R1OUT R1IN 1 RTS TD CTS RD GND GND 8 PERIPHERAL 13 T2IN 8 2801 F10 2801 F11 Figure 10. Power-Saving Receivers-Active Mode 5V 3V 3 1.8V Figure 11. Cellphone Peripheral Interface 10 8 9 µP VCC VL 1.8V TO 5.5V 3 5V LTC2801 10 8 PS 9 MODE µP TOUT 2 11 TIN LTC2802 VL MODE OFF ON TOUT 2 RIN 1 12 ROUT GND 6 1.8V TO 5.5V 10 8 R T 9 VCC VL VCC VL 11 6 ON/OFF T2OUT 4 14 T1IN T1OUT 3 15 R2OUT R2IN 2 16 R1OUT R1IN 1 GND 1.8V TO 5.5V 3 10 8 PS MODE R T 9 VCC VL 8 2801 F13 Figure 13. 5V Microprocessor Interface LTC2802 LTC2804-1 13 T2IN GND 2801 F12 Figure 12. 1.8V Microprocessor Interface 3 12 PS 11 TIN RIN 1 12 ROUT 5 VCC Figure 14. Power-Saving Shutdown Mode 1.8V TO 5.5V 5 LTC2802 12 10 PS R T MODE 11 VCC VL LTC2803 PS MODE 13 T2IN TOUT 2 11 TIN TOUT 2 11 TIN RIN 1 GND 6 Figure 15. Half-Duplex on Single Line, Separate ROUT, TIN 12 RIN 1 12 ROUT 3.3k 15 R2OUT R2IN 2 6 T1OUT 3 3.3k 16 R1OUT R1IN 1 GND GND 2801 F15 T2OUT 4 14 T1IN 3.3k 12 ROUT 2801 F14 2801 F16 Figure 16. Half-Duplex on Single Line 8 2801 F17 Figure 17. Half-Duplex Dual Transceiver 2801234fe LTC2801/LTC2802/ LTC2803/LTC2804 Typical Applications 2.5V TO 5.5V 5 13 4 14 3 12 C4 2µF 3k CL 2801 F18 DATA RATE CL (nF) LTC2803 LTC2804 (kbps) 5 X X 100 2 X X 250 0.5 X 1000 L1 10µH VCC 7 SW LTC2803 VL 9 CAP 5 C1 470nF 12 VCC SW LTC2803 VL CAP 7 9 13 T2IN T2OUT 4 13 T2IN T2OUT 4 14 T1IN T1OUT 3 14 T1IN T1OUT 3 15 R2OUT R2IN 2 15 R2OUT R2IN 2 16 R1OUT R1IN 1 16 R1OUT R1IN 1 Figure 18. Driving Larger Loads GND VDD 8 6 VEE 17 GND VDD 8 6 VEE 17 2801 F19 C2 2µF C3 2µF ANY COMBINATION LTC2801/LTC2802/LTC2803/LTC2804 Figure 19. Quad Transceiver (2.5V < VCC < 5.5V) 1.8V TO 5.5V C5 220nF 12 VL LTC2803 3V TO 25V –25V TO 0V OFF ON 2 R2IN R2OUT 15 1 R2IN R1OUT 16 11 5 7 MODE PS VCC T2IN SW T1IN GND VDD 8 6 VCC = 1.8V DRIVERS DISABLED VL 0V 10 VCC = 1.8V DRIVERS LOADED VSW 5V/DIV VCC = 5.5V DRIVERS DISABLED 13 14 VEE 17 VCC = 5.5V DRIVERS LOADED 200ns/DIV 2801 F21 Figure 21. Typical SW Pin Waveforms 2801 F20 NOTES: 1. NO L1 OR C2-C4 NEEDED. 2. RECEIVERS ACTIVE MODE SHOWN HAS NO DC HYSTERESIS. 3. SEE DUTY CYCLE GRAPH IN TYPICAL PERFORMANCE SECTION. Figure 20. 100kbps Dual Inverting Level Translator (IL = 15µA Static) 2801234fe 13 LTC2801/LTC2802/ LTC2803/LTC2804 Package Description DE/UE Package 12-Lead Plastic DFN (4mm × 3mm) (Reference LTC DWG # 05-08-1695 Rev D) 0.70 p0.05 3.60 p0.05 2.20 p0.05 3.30 p0.05 1.70 p 0.05 PACKAGE OUTLINE 0.25 p 0.05 0.50 BSC 2.50 REF RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 4.00 p0.10 (2 SIDES) 7 R = 0.115 TYP 0.40 p 0.10 12 R = 0.05 TYP PIN 1 TOP MARK (NOTE 6) 0.200 REF 3.30 p0.10 3.00 p0.10 (2 SIDES) 1.70 p 0.10 0.75 p0.05 6 0.25 p 0.05 1 PIN 1 NOTCH R = 0.20 OR 0.35 s 45o CHAMFER (UE12/DE12) DFN 0806 REV D 0.50 BSC 2.50 REF 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING PROPOSED TO BE A VARIATION OF VERSION (WGED) IN JEDEC PACKAGE OUTLINE M0-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 2801234fe 14 LTC2801/LTC2802/ LTC2803/LTC2804 Package Description DHC Package 16-Lead Plastic DFN (5mm × 3mm) (Reference LTC DWG # 05-08-1706) 0.65 ±0.05 3.50 ±0.05 1.65 ±0.05 2.20 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 4.40 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 5.00 ±0.10 (2 SIDES) R = 0.20 TYP 3.00 ±0.10 (2 SIDES) 9 R = 0.115 TYP 0.40 ± 0.10 16 1.65 ± 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) PIN 1 NOTCH 0.200 REF 0.75 ±0.05 0.00 – 0.05 8 1 0.25 ± 0.05 0.50 BSC (DHC16) DFN 1103 4.40 ±0.10 (2 SIDES) BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJED-1) IN JEDEC PACKAGE OUTLINE MO-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 2801234fe 15 LTC2801/LTC2802/ LTC2803/LTC2804 Package Description GN Package 16-Lead Plastic SSOP (Narrow .150 Inch) (Reference LTC DWG # 05-08-1641) .189 – .196* (4.801 – 4.978) .045 ±.005 16 15 14 13 12 11 10 9 .254 MIN .009 (0.229) REF .150 – .165 .229 – .244 (5.817 – 6.198) .0165 ± .0015 .150 – .157** (3.810 – 3.988) .0250 BSC RECOMMENDED SOLDER PAD LAYOUT 1 .015 ± .004 × 45° (0.38 ± 0.10) .007 – .0098 (0.178 – 0.249) .0532 – .0688 (1.35 – 1.75) 2 3 4 5 6 7 8 .004 – .0098 (0.102 – 0.249) 0° – 8° TYP .016 – .050 (0.406 – 1.270) NOTE: 1. CONTROLLING DIMENSION: INCHES INCHES 2. DIMENSIONS ARE IN (MILLIMETERS) .008 – .012 (0.203 – 0.305) TYP .0250 (0.635) BSC GN16 (SSOP) 0204 3. DRAWING NOT TO SCALE *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 2801234fe 16 LTC2801/LTC2802/ LTC2803/LTC2804 Revision History (Revision history begins at Rev E) REV DATE DESCRIPTION PAGE NUMBER E 5/10 Replaced Product Selection Guide 1 Labeled packages with appropriate part numbers in Pin Configuration section 2 Changed title of Table 1 in Mode Control section 8 Updated Feature Summary section 9 Revised first sentence of Power Saving Modes section 10 2801234fe Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 17 LTC2801/LTC2802/ LTC2803/LTC2804 Typical Application L1 10µH 1.8V TO 5.5V + C1 220nF C4 1µF – * 5 DC-DC 1.8V TO 5.5V 12 C5 220nF * VCC 11 PPX PPY µP 10 TXD PPZ RXD VCC 7 9 SW CAP LTC2804 VL PS MODE 13 T2IN T2OUT 4 14 T1IN T1OUT 3 15 R2OUT R2IN 2 16 R1OUT R1IN 1 GND VDD 8 6 CTS RX UART RTS TX VEE C2 1µF 17 C3 1µF 2801 F22 *ADDITIONAL BYPASS CAPACITOR AS NEEDED Figure 22. Diagnostic Port Operating Directly Off Unregulated Battery Voltage Related Parts PART NUMBER DESCRIPTION COMMENTS LT1780/LT1781 2-Driver/2-Receiver RS232 Transceiver Single 5V Supply with 0.1μF Capacitors, 15kV ESD LTC1337 3-Driver/5-Receiver RS232 Transceiver Ultralow Power for DTE Applications LTC1338 5-Driver/3-Receiver RS232 Transceiver Ultralow Power for DCE Applications LT1039/LT1039-16 3-Driver/3-Receiver RS232 Transceiver 30kΩ Input Impedance for Multidrop Applications LTC1348 3-Driver/5-Receiver RS232 Transceiver True RS232 Levels on 3.3V Supply 2801234fe 18 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 l FAX: (408) 434-0507 l www.linear.com LT 0510 REV E • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2005