LTC2801IDE-PBF

LTC2801/LTC2802/ LTC2803/LTC2804 1.8V to 5.5V RS-232 Single and Dual Transceivers FEATURES n n n DESCRIPTION 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. 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. Line sharing and half-duplex operation are also supported. n n n n n n 1.8V to 5.5V Supply Voltage Single and Dual Transceivers 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 Low-Power 1μA Shutdown and 15μA ReceiversActive Modes No Damage or Latch-Up to ±10kV ESD on RS-232 Interface Logic Supply Pin for Easy Level-Shifting to UART or Microprocessor Low-Latency Output Enable Allows Line Sharing and Half-Duplex Operation True RS-232 Compliant Output Levels Small Footprint: LTC2801/LTC2802 4mm × 3mm DFN Package LTC2803/LTC2804 Narrow SSOP-16 and 5mm × 3mm DFN Packages PRODUCT SELECTION GUIDE PART NUMBER LTC2801 LTC2802 LTC2803 LTC2803-1 LTC2804 LTC2804-1 DRIVERS 1 1 2 2 2 2 RECEIVERS 1 1 2 2 2 2 PACKAGE 12-Lead DFN 12-Lead DFN 16-Lead DFN 16-Lead Narrow SSOP 16-Lead DFN 16-Lead Narrow SSOP APPLICATIONS n n n Battery-Powered Systems Computers and Consumer Electronics Diagnostic Ports L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION 1.8V TO 5.5V L1 10μH LTC2802 at 1.8V and 1Mbps C4 1μF VCC VL PS LTC2802 SW C1 220nF CAP 2V/DIV TIN OFF ON MODE TIN TOUT 5V/DIV TOUT ROUT RIN 2V/DIV ROUT GND VDD C2 1μF VEE C3 1μF 2801 TA01a VCC = VL = 1.8V 400ns/DIV WRAPPING DATA TOUT LOAD = 250pF + RIN ROUT LOAD = 150pF 2801 TA01b 2801234fc 1 LTC2801/LTC2802/ LTC2803/LTC2804 ABSOLUTE MAXIMUM RATINGS (Note 1) 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 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 PIN CONFIGURATION 1-Driver/1-Receiver TOP VIEW RIN TOUT VCC VDD SW GND 1 2 3 4 5 6 VEE 13 12 ROUT 11 TIN 10 VL 9 8 7 MODE PS CAP 2-Driver/2-Receiver TOP VIEW R1IN R2IN T1OUT T2OUT VCC VDD SW GND 1 2 3 4 5 6 7 8 VEE 17 16 R1OUT 15 R2OUT 14 T1IN 13 T2IN 12 VL 11 MODE 10 PS 9 CAP 2-Driver/2-Receiver TOP VIEW R1IN R2IN T1OUT T2OUT VCC VDD SW GND 1 2 3 4 5 6 7 8 16 R1OUT 15 R2OUT 14 T1IN 13 T2IN 12 VL 11 ON/OFF 10 CAP 9 VEE DE PACKAGE 12-LEAD (4mm 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 DHC PACKAGE 16-LEAD (5mm 3mm) PLASTIC DFN GN PACKAGE 16-LEAD (NARROW 0.150) PLASTIC SSOP 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 TJMAX = 125°C, θJA = 110°C/W, θJC = 40°C/W (4 Layer) ORDER INFORMATION LEAD FREE FINISH LTC2801CDE#PBF LTC2801IDE#PBF LTC2802CDE#PBF LTC2802IDE#PBF LTC2803CDHC#PBF LTC2803IDHC#PBF LTC2804CDHC#PBF TAPE AND REEL LTC2801CDE#TRPBF LTC2801IDE#TRPBF LTC2802CDE#TRPBF LTC2802IDE#TRPBF LTC2803CDHC#TRPBF LTC2803IDHC#TRPBF LTC2804CDHC#TRPBF PART MARKING* 2801 2801 2802 2802 2803 2803 2804 PACKAGE DESCRIPTION 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 16-Lead (5mm × 3mm) Plastic DFN 16-Lead (5mm × 3mm) Plastic DFN 16-Lead (5mm × 3mm) Plastic DFN TEMPERATURE RANGE 0°C to 70°C –40°C to 85°C 0°C to 70°C –40°C to 85°C 0°C to 70°C –40°C to 85°C 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/ 2801234fc 2 LTC2801/LTC2802/ LTC2803/LTC2804 ELECTRICAL CHARACTERISTICS SYMBOL Power Supplies ICC VCC Supply Current Outputs Unloaded Normal Mode (Note 3) Receivers Active Mode Shutdown Mode Outputs Unloaded Normal Mode (LTC2801, LTC2802) Normal Mode (LTC2803, LTC2804) Receivers Active Mode Shutdown Mode RL = 3kΩ RL = 3kΩ VL = VCC = 5.5V; VTOUT = 0V VL = VCC = VDD = VEE = 0V; VTOUT = ±2V Low High 2.3 1 1 0.08 0.15 15 1 –5 5 –5.7 6.2 0.6 l l 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. PARAMETER CONDITIONS MIN TYP MAX UNITS l l l l l l l l 10 10 0.15 0.30 30 10 mA μA μA mA mA μA μA V V V IL VL Supply Current Driver VOLD VOHD VHYSD IOSD IPOLD IOLD Receiver VIR VILR VIHR VHYSR VOLR VOHR RIN IOSR Logic Logic Input Voltage Threshold IIN VDD Logic Input Current Regulated VDD Output Voltage Driver RL = 3kΩ (Note 3) LTC2801, LTC2802: VTIN = VL LTC2803, LTC2804: VT1IN = VL , VT2IN = 0V Driver RL = 3kΩ (Note 3) LTC2801, LTC2802: VTIN = VL LTC2803, LTC2804: VT1IN = VL , VT2IN = 0V Power Supply Generator 7 V l l Output Voltage Output Voltage Logic Input Hysteresis Output Short Circuit Current Power-Off Output Leakage Current Output Leakage Current ±35 ±0.1 ±0.1 ±70 ±10 ±10 mA µA µA l Shutdown or Receivers Active or Drivers Disabled Modes, –15V ≤ VTOUT ≤ 15V Input Thresholds Input Thresholds Input Thresholds Input Hysteresis Output Voltage Output Voltage Input Resistance Output Short Circuit Current Receivers Active Mode Normal Mode, Input Low Normal Mode, Input High Normal Mode Output Low, IROUT = 1mA (Sinking) Output High, IROUT = – 1mA (Sourcing) –15V ≤ VRIN ≤ 15V VL = 5.5V; 0V ≤ VROUT ≤ VL l l l l l l l l 0.8 0.8 0.1 VL – 0.4 3 1.5 1.3 1.7 0.4 0.2 VL – 0.2 5 ±25 2.4 2.5 1.0 0.4 7 ±50 0.67 • VL ±1 V V V V V V kΩ mA V μA 0.4 VEE Regulated VEE Output Voltage – 6.3 V 2801234fc 3 LTC2801/LTC2802/ LTC2803/LTC2804 SWITCHING CHARACTERISTICS SYMBOL PARAMETER Maximum Data Rate 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. CONDITIONS LTC2801, LTC2803 (Note 3) RL = 3kΩ, CL = 2.5nF RL = 3kΩ, CL = 1nF LTC2802, LTC2804 (Note 3) RL = 3kΩ, CL = 2.5nF RL = 3kΩ, CL = 1nF RL = 3kΩ, CL = 250pF Driver SR(D) Driver Slew Rate LTC2801, LTC2803 (Figure 1) VCC = VL = 1.8V, RL = 3kΩ, CL = 2.5nF VCC = VL = 5.5V, RL = 3kΩ, CL = 50pF LTC2802, LTC2804 (Figure 1) VCC = VL = 1.8V, RL = 3kΩ, CL = 2.5nF VCC = VL = 5.5V, RL = 3kΩ, CL = 50pF tPHLD, tPLHD Driver Propagation Delay RL = 3kΩ, CL = 50pF (Figure 2) LTC2801, LTC2803 LTC2802, LTC2804 RL = 3kΩ, CL = 50pF (Figure 2) LTC2801, LTC2803 LTC2802, LTC2804 PS = VL, MODE = ↑, RL = 3kΩ, CL = 50pF (Figure 4) PS = VL, MODE = ↓, RL = 3kΩ, CL = 50pF (Figure 4) CL = 150pF (Figure 3) CL = 150pF (Figure 3) CL = 150pF (Figure 3) PS = MODE = ↑ or ON/OFF = ↑, RL = 1kΩ, CL = 150pF (Figure 5) PS = MODE = ↓ or ON/OFF = ↓, RL = 1kΩ, CL = 150pF (Figure 5) (Notes 3 and 4) l l l l l l l l l l l l l l l l MIN 100 250 100 250 1000 TYP MAX UNITS kbps kbps kbps kbps kbps 4 30 4 150 1 0.2 100 50 0.6 0.3 2 2 2 0.5 V/μs V/μs V/μs V/μs μs μs ns ns μs μs tSKEWD Driver Skew tPZHD, tPZLD tPHZD, tPLZD Receiver tPHLR, tPLHR tSKEWR tRR, tFR tPZHR, tPZLR tPHZR, tPLZR Driver Output Enable Time Driver Output Disable Time Receiver Propagation Delay Receiver Skew Receiver Rise or Fall Time Shutdown to Receiver Output Enable Receiver Output Disable upon Shutdown l 0.2 50 60 5 0.15 0.4 200 15 0.3 μs ns ns μs μs Power Supply Generator VDD/VEE Supply Rise Time l 0.2 2 ms 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. 2801234fc 4 LTC2801/LTC2802/ LTC2803/LTC2804 TEST CIRCUITS TOUT TIN tTHL TOUT SR(D) = TIN tr, tf ≤ 40ns 6V tTHL or tTLH 3V –3V 3V –3V tTLH VOHD VOLD 2801F02 VL 0V TIN RL CL Figure 1. Driver Slew Rate Measurement TOUT TIN TIN RL CL TOUT 1/2 VL tPHLD 0V tSKEWD = |tPHLD – tPLHD| TIN tr, tf ≤ 40ns 1/2 VL VL 0V tPLHD VOHD 0V VOLD 2801F02 Figure 2. Driver Timing Measurement ROUT RIN 3V 1.5V tPHLR 1.5V –3V tPLHR VOHR 1/2 VL tSKEWR = |tPHLR – tPLHR| 1/2 VL VOLR 2801F03 RIN CL ROUT RIN tr, tf ≤ 40ns Figure 3. Receiver Timing Measurement MODE VL 1/2 VL tPZHD 1/2 VL 0V tPHZD 5V tPZLD tPLZD 0V –5V VOLD + 0.5V VOLD VOHD – 0.5V VOHD 0V 0 OR VL RL CL TOUT TOUT MODE TOUT 2801F04 MODE tr, tf ≤ 40ns Figure 4. Driver Enable/Disable Times 2801234fc 5 LTC2801/LTC2802/ LTC2803/LTC2804 TEST CIRCUITS GND VL PS AND MODE RL –3V OR 3V ROUT ROUT PS AND MODE CL ROUT PS AND MODE tr, tf ≤ 40ns tPZLR 1/2 VL VL 1/2 VL tPZHR 1/2 VL tPLZR VL VOLR + 0.5V VOLR 2801F05 1/2 VL 0V tPHZR V VOHR – 0.5V OHR 0V Figure 5. Receiver Enable/Disable Times TYPICAL PERFORMANCE CHARACTERISTICS LTC2803 at 1.8V and 250kbps T1IN 2V/DIV T1OUT T2OUT 10V/DIV R1OUT 2V/DIV R2OUT 2V/DIV 10V/DIV R1OUT R2OUT 2V/DIV T1OUT T2OUT TA = 25°C, VCC = VL = 3.3V unless otherwise noted. LTC2804 at 1.8V and 1Mbps 3.0 T1IN SUPPLY CURRENT (mA) 2.5 Drivers Disabled Mode Supply Current vs Supply Voltage TA = 85°C TA = 25°C TA = –40°C VCC = VL 2.0 1.5 1.0 0.5 0 VCC = VL = 1.8V 2μs/DIV WRAPPING DATA TOUT LOAD = 1nF + RIN ROUT LOAD = 150pF 2801 G01 VCC = VL = 1.8V 400ns/DIV WRAPPING DATA TOUT LOAD = 250pF + RIN ROUT LOAD = 150pF 1 2 5 3 4 SUPPLY VOLTAGE (V) 6 2801 G03 2801 G02 Supply Current vs Supply Voltage (Dual Transceiver) 60 50 SUPPLY CURRENT (mA) 40 125kbps 30 20 10 LTC2804 LTC2803 0 1 2 3 4 5 SUPPLY VOLTAGE (V) 6 2801 G04 Supply Current vs Data Rate 100 ALL DRIVERS SWITCHING VCC = VL = 1.8V RL = 3k 1nF 1nF 60 250pF 40 250pF LTC2804 LTC2802 0 200 600 400 DATA RATE (kbps) 800 1000 2801 G05 Supply Current vs Load Capacitance (Dual Transceiver) 100 250kbps 80 SUPPLY CURRENT (mA) 125kbps SUPPLY CURRENT (mA) ALL DRIVERS SWITCHING VCC = VL RL = 3k 250kbps CL = 1nF 80 60 40 20.8kbps 20 VCC = VL = 1.8V LTC2804 RL = 3k LTC2803 ALL DRIVERS SWITCHING 1 3 2 4 LOAD CAPACITANCE (nF) 5 2801 G06 20.8kbps 20 0 0 2801234fc 6 LTC2801/LTC2802/ LTC2803/LTC2804 TYPICAL PERFORMANCE CHARACTERISTICS Receiver Input Threshold vs Temperature 3.0 2.5 THRESHOLD VOLTAGE (V) 2.0 1.5 1.0 0.5 0 –50 –25 INPUT LOW VL = 5.5V VL = 3.3V VL = 1.8V INPUT HIGH OUTPUT VOLTAGE (V) 6 5 4 3 2 1 0 TA = 25°C, VCC = VL = 3.3V unless otherwise noted. Receiver Output Voltage vs Load Current VL = 5.5V VL = 3.3V VL = 1.8V POSITIVE DUTY CYCLE (%) 100 Receiver Output Duty Cycle RIN = ±3V CL = 150pF RECEIVERS ALIVE MODE 60 NORMAL MODE 80 40 20 0 0 1 2 3 4 5 6 LOAD CURRENT (mA) 7 8 10 100 1000 DATA RATE (kbps) VL = 5.5V VL = 3.3V VL = 1.8V 10000 2801 GO9 50 25 75 0 TEMPERATURE (°C) 100 125 2801 GO7 2801 GO8 Driver Slew Rate vs Load Capacitance 80 70 60 SLEW RATE (V/μs) 50 40 30 20 10 0 0 1 4 3 LOAD CAPACITANCE (nF) 2 5 2801 G10 Driver Short-Circuit Current vs Temperature 60 SHORT-CIRCUIT CURRENT (mA) 50 SINKING 40 30 20 10 REGULATOR CAN LIMIT FURTHER 0 50 –50 –25 25 75 0 TEMPERATURE (°C) SOURCING LEAKAGE CURRENT (A) 10–6 10–7 10–8 10–9 Shutdown or Drivers Disabled Mode Driver Leakage vs Temperature FALLING (LTC2802/04) RISING (LTC2802/04) FALLING (LTC2801/03) RISING (LTC2801/03) V(TOUT) = 15V OR V(TOUT) = –15V 10–10 10–11 –50 –25 100 125 50 25 75 0 TEMPERATURE (°C) 100 125 2801 G11 2801 G12 Logic Input Threshold vs VL Supply Voltage 3.0 2.5 THRESHOLD VOLTAGE (V) 2.0 1.5 1.0 INPUT LOW 0.5 0 5V/DIV TA = 85°C TA = 25°C TA = –40°C INPUT HIGH LTC2804 Driver Outputs Exiting Shutdown LTC2804 Driver Outputs Enable/Disable 2V/DIV MODE AND PS 2V/DIV MODE T1OUT 5V/DIV T2OUT T1OUT T2OUT 1 2 3 4 5 VL SUPPLY VOLTAGE (V) 6 2801 G13 100μs/DIV VCC = 3.3V VL = 1.8V LOAD = 3k + 2.5nF 2801 G14 2μs/DIV VCC = 3.3V VL = 1.8V LOAD = 3k + 250nF 2801 G15 2801234fc 7 LTC2801/LTC2802/ LTC2803/LTC2804 PIN FUNCTIONS PIN NUMBER PIN NAME VCC VDD VEE SW GND CAP VL TIN (T1IN, T2IN) TOUT (T1OUT, T2OUT) RIN (R1IN, R2IN) ROUT (R1OUT, R2OUT) PS MODE ON/OFF *Backside thermal pad 2801 2802 3 4 13* 5 6 7 10 11 2 1 12 8 9 — 2803 2804 5 6 17* 7 8 9 12 14, 13 3, 4 1, 2 16, 15 10 11 — 2803-1 2804-1 COMMENTS 5 6 9 7 8 10 12 14, 13 3, 4 1, 2 16, 15 — — 11 Input Supply (1.8V-5.5V). Bypass to GND with a 1μF capacitor. Generated Positive Supply Voltage for RS-232 Driver (7V). Connect a 1μF capacitor between VDD and GND. Generated Negative Supply Voltage for RS-232 Driver (–6.3V). Connect a 1μF capacitor between VEE and GND. Switch Pin. Connect a 10μH inductor between SW and VCC. Ground. Charge Pump Capacitor for Generated Negative Supply Voltage. Connect a 220nF capacitor between CAP and SW. 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. Driver Input(s), referenced to VL. RS-232 Driver Output(s). RS-232 Receiver Input(s). Includes internal 5kΩ termination resistor(s). 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. Power Supply control pin, referenced to VL. Enables the integrated DC-DC converter. Mode control pin, referenced to VL. See Table 1 for functionality. 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. MODE CONTROL Table 1. LTC2801-LTC2804 MODE NAME SHUTDOWN RECEIVERS ACTIVE DRIVERS DISABLED NORMAL PS L L H H MODE L H L H RECEIVER OUTPUT(S) HI-Z ON ON ON DC-DC OFF OFF ON ON DRIVER OUTPUT(S) HI-Z HI-Z HI-Z ON IVCC* 1μA 1μA 2.1mA 2.3mA IVL* 1μA 15μA 80μA OR 150μA 80μA OR 150μA Table 2. LTC2803-1, LTC2804-1 MODE NAME SHUTDOWN NORMAL ON/OFF L H RECEIVER OUTPUTS HI-Z ON DC-DC OFF ON DRIVER OUTPUTS HI-Z ON IVCC* 1μA 2.3mA IVL* 1μA 150μA *Typical currents for static drivers. Normal mode currents are for unloaded outputs. 2801234fc 8 LTC2801/LTC2802/ LTC2803/LTC2804 FEATURE SUMMARY FEATURE DRIVERS and RECEIVERS PACKAGE 1.8V - 5.5V OPERATION 1.8V - 5.5V LOGIC SUPPLY (VL) SHUTDOWN (1μA) RECEIVER(S) ACTIVE (15μA) DRIVER DISABLE 100kb/s for RL = 3kΩ, CL = 2.5nF 250kb/s for RL = 3kΩ, CL = 1nF 1Mb/s for RL = 3kΩ, CL = 250pF 2801 1+1 DE l l l l l l l 2802 1+1 DE l l l l l l l l 2803 2+2 DHC l l l l l l l 2803-1 2+2 GN l l l 2804 2+2 DHC l l l l l 2804-1 2+2 GN l l l l l l l l l l l BLOCK DIAGRAM L1 10μH 1.8V TO 5.5V C4 1μF VCC SW CAP VDD 1.8V TO 5.5V C5 220nF VL BOOST REGULATOR VEE C3 1μF C2 1μF C1 220nF VL T2IN T1IN VDD T2OUT T1OUT VL ** ** ** R2OUT GND VEE R2IN ** 5k R1OUT VL LTC2801 LTC2802 LTC2803 LTC2804 LTC2803-1 LTC2804-1 PS MODE ON/OFF GND CONTROL 5k ** LTC2803 LTC2804 LTC2803-1 LTC2804-1 R1IN 2801BD GND 2801234fc 9 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. DC-DC Converter 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 1.8V TO 5.5V C4 1μF VCC C1 220nF SW CAP VDD 1.8V TO 5.5V C5* 220nF VL BOOST REGULATOR VEE C3 1μF C2 1μF ANY VOLTAGE FROM 1.8V TO 5.5V ANY VOLTAGE FROM 1.8V TO 5.5V VCC VL EXTERNAL DEVICE RS-232 2801F07 Figure 7. VCC and VL Are Independent Power-Saving Modes When the DC-DC converter and drivers are turned off (PS 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 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. 2801234fc 2801F06 *OMIT IF VL IS CONNECTED TO VCC 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). 10 LTC2801/LTC2802/ LTC2803/LTC2804 APPLICATIONS INFORMATION Table 3. Recommended Inductors PART NUMBER ISAT MAX DCR (mA) (Ω) 1.2 0.85 1.1 SIZE (mm) MANUFACTURER LQH2MCN100K02L 225 LBC2016T100K FSLB2520-100K 245 220 2 × 1.6 × 0.95 Murata www.murata.com 2 × 1.6 × 1.6 Taiyo Yuden www.t-yuden.com 2.5 × 2 × 1.6 Toko www.tokoam.com 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). Capacitor Selection 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. Table 4. Recommended Ceramic Capacitor Manufacturers MANUFACTURER Murata TDK Taiyo Yuden AVX Kemet URL www.murata.com www.tdk.com www.t-yuden.com www.avxcorp.com www.kemet.com C1 GND GND C2 VL GND C5 VCC GND C4 L1 GND TOP VIEW = VIA C3 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 4.5V TO 5.5V INRUSH CURRENT VCC C3 C4 1μF C2 1μF SCALE R1 WITH C1, C2, 1/C4 2801F08 C1 GND GND C2 VL GND C5 VCC GND C4 L1 L1 10μH C1 220nF R1 1Ω 1/8W SW CAP GND VDD GND TOP VIEW = VIA 2801F09 Figure 8. Supply Overshoot Protection for Input Supplies of 4.5V or Higher Figure 9. Recommended Board Layouts for (a) Single and (b) Dual Transceiver Parts 2801234fc 11 LTC2801/LTC2802/ LTC2803/LTC2804 TYPICAL APPLICATIONS 1.8V TO 5.5V 5 12 11 RA ON 10 VCC LTC2803 VL MODE PS T2OUT 4 T1OUT 3 R2IN 2 R1IN 1 GND 8 2801F10 5 VCC 12 VL 1.8V TO 5.5V CELL PHONE VBATT RTS TD CTS RD 10 PS 11 MODE 13 T2IN 14 T1IN 15 R2OUT 16 R1OUT GND 8 2801F11 LTC2804 PERIPHERAL T2OUT 4 T1OUT 3 R2IN 2 R1IN 1 RTS TD CTS RD 13 T2IN 14 T1IN 15 R2OUT 16 R1OUT Figure 10. Power-Saving Receivers-Active Mode 5V 3 10 8 9 μP 11 TIN TOUT 2 VCC LTC2801 VL PS MODE μP 11 TIN 3V 3 10 8 9 VCC LTC2802 VL PS MODE Figure 11. Cellphone Peripheral Interface 1.8V TO 5.5V 5 12 VCC LTC2804-1 VL 1.8V 5V OFF ON 11 ON/OFF T2OUT 4 T1OUT 3 R2IN 2 R1IN 1 GND 13 T2IN TOUT 2 14 T1IN 15 R2OUT 12 ROUT GND 6 RIN 1 12 ROUT GND RIN 1 16 R1OUT 2801F12 6 2801F13 8 2801F14 Figure 12. 1.8V Microprocessor Interface 1.8V TO 5.5V 3 10 8 RT 9 VCC LTC2802 VL PS MODE Figure 13. 5V Microprocessor Interface 1.8V TO 5.5V 3 10 8 RT 9 VCC LTC2802 VL PS MODE Figure 14. Power-Saving Shutdown Mode 1.8V TO 5.5V 5 12 10 RT 11 VCC LTC2803 VL PS MODE T2OUT 4 R2IN 2 T1OUT 3 R1IN 1 GND 13 T2IN 11 TIN TOUT 2 3.3k 12 ROUT GND 6 2801F15 11 TIN TOUT 2 3.3k 15 R2OUT 14 T1IN RIN 1 12 ROUT GND 6 RIN 1 3.3k 16 R1OUT 2801F16 8 2801F17 Figure 15. Half-Duplex on Single Line, Separate ROUT, TIN Figure 16. Half-Duplex on Single Line Figure 17. Half-Duplex Dual Transceiver 2801234fc 12 LTC2801/LTC2802/ LTC2803/LTC2804 TYPICAL APPLICATIONS 2.5V TO 5.5V L1 10μH 5 13 4 C4 2μF 12 VCC LTC2803 VL SW CAP 7 9 C1 470nF 5 12 VCC LTC2803 VL SW CAP 7 9 14 3 3k CL 2801F18 13 T2IN 14 T1IN 15 R2OUT 16 R1OUT GND VDD 6 T2OUT 4 T1OUT 3 R2IN 2 R1IN 1 VEE 17 13 T2IN 14 T1IN 15 R2OUT 16 R1OUT GND 8 VDD 6 T2OUT 4 T1OUT 3 R2IN 2 R1IN 1 VEE 17 DATA RATE CL (nF) LTC2803 LTC2804 (kbps) 5 X X 100 2 X X 250 0.5 X 1000 Figure 18. Driving Larger Loads 8 2801F19 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 2 R2IN 1 R2IN R2OUT 15 R1OUT 16 VL 0V VSW 5V/DIV VCC = 1.8V DRIVERS DISABLED VCC = 1.8V DRIVERS LOADED VCC = 5.5V DRIVERS DISABLED OFF ON 11 5 7 MODE VCC SW GND 8 PS T2IN T1IN VDD 6 VEE 17 10 13 14 VCC = 5.5V DRIVERS LOADED 200ns/DIV 2801F21 Figure 21. Typical SW Pin Waveforms 2801F20 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) 2801234fc 13 LTC2801/LTC2802/ LTC2803/LTC2804 TYPICAL APPLICATIONS DE/UE Package 12-Lead Plastic DFN (4mm × 3mm) (Reference LTC DWG # 05-08-1695 Rev D) 4.00 ± 0.10 (2 SIDES) 0.70 ± 0.05 3.30 ± 0.05 1.70 ± 0.05 PIN 1 TOP MARK (NOTE 6) R = 0.05 TYP 3.00 ± 0.10 (2 SIDES) 3.30 ± 0.10 1.70 ± 0.10 PIN 1 NOTCH R = 0.20 OR 0.35 × 45° CHAMFER 1 0.50 BSC 2.50 REF 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD (UE12/DE12) DFN 0806 REV D 7 R = 0.115 TYP 0.40 ± 0.10 12 3.60 ± 0.05 2.20 ± 0.05 0.25 ± 0.05 0.50 BSC 2.50 REF RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 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 PACKAGE OUTLINE 0.200 REF 0.75 ± 0.05 6 0.25 ± 0.05 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 DHC Package 16-Lead Plastic DFN (5mm × 3mm) (Reference LTC DWG # 05-08-1706) 5.00 ± 0.10 (2 SIDES) 0.65 ± 0.05 R = 0.20 TYP R = 0.115 TYP 9 16 0.40 ± 0.10 3.50 ± 0.05 1.65 ± 0.05 2.20 ± 0.05 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) PACKAGE OUTLINE 3.00 ± 0.10 1.65 ± 0.10 (2 SIDES) (2 SIDES) PIN 1 NOTCH (DHC16) DFN 1103 8 0.25 ± 0.05 0.50 BSC 4.40 ± 0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 0.200 REF 0.75 ± 0.05 4.40 ± 0.10 (2 SIDES) 1 0.25 ± 0.05 0.50 BSC 0.00 – 0.05 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 BOTTOM VIEW—EXPOSED PAD 2801234fc 14 LTC2801/LTC2802/ LTC2803/LTC2804 PACKAGE DESCRIPTION GN Package 16-Lead Plastic SSOP (Narrow .150 Inch) (Reference LTC DWG # 05-08-1641) .045 ± .005 .189 – .196* (4.801 – 4.978) 16 15 14 13 12 11 10 9 .009 (0.229) REF .254 MIN .150 – .165 .229 – .244 (5.817 – 6.198) .150 – .157** (3.810 – 3.988) .0165 ± .0015 .0250 BSC 1 .015 ± .004 × 45° (0.38 ± 0.10) .0532 – .0688 (1.35 – 1.75) 23 4 56 7 8 .004 – .0098 (0.102 – 0.249) RECOMMENDED SOLDER PAD LAYOUT .007 – .0098 (0.178 – 0.249) 0° – 8° TYP .016 – .050 (0.406 – 1.270) NOTE: 1. CONTROLLING DIMENSION: INCHES INCHES 2. DIMENSIONS ARE IN (MILLIMETERS) 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 .008 – .012 (0.203 – 0.305) TYP .0250 (0.635) BSC GN16 (SSOP) 0204 2801234fc 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. 15 LTC2801/LTC2802/ LTC2803/LTC2804 TYPICAL APPLICATION 1.8V TO 5.5V L1 10μH C4 1μF * DC-DC 1.8V TO 5.5V C5 220nF 5 12 10 PS PPX PPY TXD μP PPZ RXD 11 MODE T2OUT 4 T1OUT 3 R2IN 2 R1IN 1 CTS RX UART RTS TX VCC VL 7 SW 9 CAP C1 220nF + – LTC2804 * VCC 13 T2IN 14 T1IN 15 R2OUT 16 R1OUT GND 8 VDD 6 C2 1μF VEE 17 C3 1μF 2801F22 *ADDITIONAL BYPASS CAPACITOR AS NEEDED Figure 22. Diagnostic Port Operating Directly Off Unregulated Battery Voltage RELATED PARTS PART NUMBER LT1780/LT1781 LTC1337 LTC1338 LT1039/LT1039-16 LTC1348 DESCRIPTION 2-Driver/2-Receiver RS232 Transceiver 3-Driver/5-Receiver RS232 Transceiver 5-Driver/3-Receiver RS232 Transceiver 3-Driver/3-Receiver RS232 Transceiver 3-Driver/5-Receiver RS232 Transceiver COMMENTS Single 5V Supply with 0.1μF Capacitors, 15kV ESD Ultralow Power for DTE Applications Ultralow Power for DCE Applications 30kΩ Input Impedance for Multi-Drop Applications True RS232 Levels on 3.3V Supply 2801234fc 16 Linear Technology Corporation (408) 432-1900 ● FAX: (408) 434-0507 ● LT 0808 REV C • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 www.linear.com © LINEAR TECHNOLOGY CORPORATION 2005