Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsInterface ICsInterface IC - transceivers RS232 2/2 SSOP 16

2801234fe

LTC2801/LTC2802/

LTC2803/LTC2804

Product Selection Guide

1.8V to 5.5V RS-232

Single and Dual Transceivers

tyPical aPPlication

FeatureS

aPPlicationS

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 stan-

dard. 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.

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 Receivers-

Active Modes

No Damage or Latchup 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/L

TC2804 Narrow SSOP-16 and

5mm × 3mm DFN Packages

Battery-Powered Systems

Computers and Consumer Electronics

Diagnostic Ports

LTC2802 at 1.8V and 1Mbps

TIN

TOUT

ROUT

2V/DIV

5V/DIV

2V/DIV

400ns/DIVV

= V

= 1.8V

WRAPPING DATA

TOUT LOAD = 250pF + RIN

ROUT LOAD = 150pF

2801 TA01b

MODE

TIN

ROUT

GND

CAP

TOUT

RIN

LTC2802

2801 TA01a

10µH

1µF

220nF

1.8V TO 5.5V

OFF ON

1µF

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.

PART NUMBER

DRIVERS AND

RECEIVERS

MAXIMUM

DATA RATE MODES* PACKAGE

LTC2801 1 + 1 0.25Mbps SD, RA, DD, AO DFN-12

LTC2802 1 + 1 1Mbps 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

Summary of content (18 pages)

PAGE 1
LTC2801/LTC2802/ LTC2803/LTC2804 1.8V to 5.5V RS-232 Single and Dual Transceivers Features n n n n n n n n n Description 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.
PAGE 2
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..............................................
PAGE 3
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.
PAGE 4
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.
PAGE 5
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.
PAGE 6
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.
PAGE 7
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.
PAGE 8
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.
PAGE 9
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.
PAGE 10
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.
PAGE 11
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.
PAGE 12
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.
PAGE 13
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.
PAGE 14
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.
PAGE 15
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.
PAGE 16
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.
PAGE 17
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.
PAGE 18
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.