LTC2803CGN-1-PBF_技术文档

LTC2801/LTC2802/

LTC2803/LTC2804

1.8V to 5.5V RS-232

Single and Dual Transceivers

FEATURES

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

logicsupplypinallowseasyinterfacingwithdifferentlogic

levels independent of the DC-DC supply.

n

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 Receivers-

Active Modes

n

No Damage or Latch-Up to 10kV ESD on RS-232

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. Line sharing and

half-duplex operation are also supported.

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

PRODUCT SELECTION GUIDE

PART NUMBER

DRIVERS

RECEIVERS

PACKAGE

LTC2801

1

2

1

2

12-Lead DFN

APPLICATIONS

LTC2802

12-Lead DFN

LTC2803

16-Lead DFN

n

Battery-Powered Systems

LTC2803-1

LTC2804

16-Lead Narrow SSOP

16-Lead DFN

n

Computers and Consumer Electronics

n

Diagnostic Ports

LTC2804-1

16-Lead Narrow SSOP

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

LTC2802 at 1.8V and 1Mbps

10μH

C4

1μF

V

SW

CAP

CC

L

TIN

2V/DIV

5V/DIV

C1

LTC2802

220nF

PS

OFF ON

MODE

TIN

TOUT

ROUT

TOUT

RIN

ROUT

GND

2V/DIV

V

EE

V

2801 TA01b

DD

V

CC

= V = 1.8V 400ns/DIV

L

WRAPPING DATA

TOUT LOAD = 250pF + RIN

ROUT LOAD = 150pF

C2

1μF

C3

1μF

2801 TA01a

2801234fc

1

LTC2801/LTC2802/

LTC2803/LTC2804

ABSOLUTE MAXIMUM RATINGS

(Note 1)

Input Supplies

PS, ON/OFF.....................................–0.3V to (V + 0.3V)

L

V ...........................................................–0.3V to 7V

RIN, R1IN, R2IN..........................................–25V to 25V

TOUT, T1OUT, T2OUT .................................–15V to 15V

CC

V ..........................................................–0.3V to 6.7V

L

Generated Supplies

ROUT, R1OUT, R2OUT....................–0.3V to (V + 0.3V)

L

V

................................................ V –0.3V to 7.5V

Operating Temperature

DD

EE

DD

CC

V ........................................................0.3V to –7.5V

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)

V

– V ..............................................................14V

EE

SW..................................................–0.3V to V + 0.3V

DD

EE

CAP.................................................. +0.3V to V – 0.3V

TIN, T1IN, T2IN, MODE................................–0.3V to 7V

GN Package ...................................................... 300°C

PIN CONFIGURATION

1-Driver/1-Receiver

2-Driver/2-Receiver

TOP VIEW

R1IN

R2IN

1

2

3

4

5

6

7

8

16 R1OUT

15 R2OUT

14 T1IN

R1IN

R2IN

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

R1OUT

R2OUT

T1IN

RIN

1

2

3

4

5

6

12 ROUT

11 TIN

TOUT

T1OUT

T2OUT

T1OUT

T2OUT

V

CC

10

9

V

L

13 T2IN

T2IN

13

17

V

CC

12 V

L

V

MODE

PS

DD

V

CC

V

L

V

11 MODE

10 PS

SW

8

DD

V

DD

ON/OFF

V

EE

SW

GND

7

CAP

SW

CAP

V

EE

GND

9

CAP

GND

V

EE

DE PACKAGE

12-LEAD (4mm s 3mm) PLASTIC DFN

= 125°C, θ = 43°C/W, θ = 4.3°C/W (4 Layer)

EXPOSED PAD (PIN 13) IS V , MUST BE SOLDERED TO PCB

DHC PACKAGE

16-LEAD (5mm s 3mm) PLASTIC DFN

= 125°C, θ = 44°C/W, θ = 4.3°C/W (4 Layer)

GN PACKAGE

16-LEAD (NARROW 0.150) PLASTIC SSOP

T

JMAX

JA JC

EE

T

JMAX

JA

JC

T

= 125°C, θ = 110°C/W, θ = 40°C/W (4 Layer)

JMAX

JA

JC

EXPOSED PAD (PIN 17) IS V , MUST BE SOLDERED TO PCB

EE

ORDER INFORMATION

LEAD FREE FINISH

LTC2801CDE#PBF

LTC2801IDE#PBF

LTC2802CDE#PBF

LTC2802IDE#PBF

LTC2803CDHC#PBF

LTC2803IDHC#PBF

LTC2804CDHC#PBF

LTC2804IDHC#PBF

LTC2803CGN-1#PBF

LTC2803IGN-1#PBF

LTC2804CGN-1#PBF

LTC2804IGN-1#PBF

TAPE AND REEL

PART MARKING*

2801

PACKAGE DESCRIPTION

TEMPERATURE RANGE

0°C to 70°C

LTC2801CDE#TRPBF

LTC2801IDE#TRPBF

LTC2802CDE#TRPBF

LTC2802IDE#TRPBF

LTC2803CDHC#TRPBF

LTC2803IDHC#TRPBF

LTC2804CDHC#TRPBF

LTC2804IDHC#TRPBF

LTC2803CGN-1#TRPBF

LTC2803IGN-1#TRPBF

LTC2804CGN-1#TRPBF

LTC2804IGN-1#TRPBF

12-Lead (4mm × 3mm) Plastic DFN

16-Lead (5mm × 3mm) Plastic DFN

16-Lead (Narrow 0.150) Plastic SSOP

2801

–40°C to 85°C

0°C to 70°C

2802

–40°C to 85°C

0°C to 70°C

2803

–40°C to 85°C

0°C to 70°C

2804

–40°C to 85°C

0°C to 70°C

28031

2803I1

28041

2804I1

–40°C to 85°C

0°C to 70°C

–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

The l denotes the speciﬁcations which apply over the full operating

temperature range, otherwise speciﬁcations are at T_A= 25°C, V_CC= 1.8V to 5.5V, V_L= 1.8V to 5.5V, Normal Mode. Typical values are

given for V_CC= V_L= 3.3V and T_A= 25°C, unless otherwise noted.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Power Supplies

I

V

Supply Current

CC

Outputs Unloaded

CC

L

Normal Mode (Note 3)

Receivers Active Mode

Shutdown Mode

2.3

1

mA

μA

l

10

1

V Supply Current

Outputs Unloaded

L

l

Normal Mode (LTC2801, LTC2802)

Normal Mode (LTC2803, LTC2804)

Receivers Active Mode

0.08

0.15

15

0.15

0.30

30

mA

μA

Shutdown Mode

1

10

μA

Driver

l

V

I

Output Voltage

R = 3kΩ

Low

High

–5

5

–5.7

6.2

V

OLD

L

Output Voltage

R = 3kΩ

L

OHD

HYSD

Logic Input Hysteresis

Output Short Circuit Current

Power-Off Output Leakage Current

Output Leakage Current

0.6

V

l

V = V = 5.5V; V = 0V

TOUT

±±3

±70.

±ꢀ7

±.7

mA

µA

OSD

POLD

OLD

L

CC

I

V = V = V = V = 0V; V = ±2V

TOUT

L

CC

DD

EE

Shutdown or Receivers Active or

Drivers Disabled Modes, –.3V ≤ V

≤ .3V

TOUT

Receiver

l

V

Input Thresholds

Input Hysteresis

Output Voltage

Receivers Active Mode

Normal Mode, Input Low

Normal Mode, Input High

Normal Mode

0.8

1.5

1.3

1.7

0.4

0.2

2.4

V

IR

ILR

2.5

.07

0.4

V

IHR

HYSR

OLR

OHR

0.1

V

Output Low, I

= 1mA (Sinking)

V

ROUT

Output Voltage

Output High, I

= –1mA (Sourcing)

V –0.4 V –0.2

L

V

ROUT

L

R

I

Input Resistance

Output Short Circuit Current

3

5

7

kΩ

mA

–15V ≤ V ≤ .3V

IN

RIN

V = 5.5V; 0V ≤ V

≤ V

L

±ꢁ3

±37

OSR

L

ROUT

Logic

l

Logic Input Voltage Threshold

Logic Input Current

0.4

0.67 • V

1

V

L

I

μA

IN

Power Supply Generator

V

Regulated V Output Voltage

Driver R = 3kΩ (Note 3)

DD

EE

DD

L

7

V

LTC2801, LTC2802: V = V

TIN

T1IN

L

LTC2803, LTC2804: V

= V , V

= 0V

T2IN

V

Regulated V Output Voltage

Driver R = 3kΩ (Note 3)

EE

L

–6.3

LTC2801, LTC2802: V = V

TIN

T1IN

L

LTC2803, LTC2804: V

= V , V

= 0V

T2IN

2801234fc

3

LTC2801/LTC2802/

LTC2803/LTC2804

SWITCHING CHARACTERISTICS

The l denotes the speciﬁcations which apply over the full operating

temperature range, otherwise speciﬁcations are at T_A= 25°C, V_CC= 1.8V to 5.5V, V_L= 1.8V to 5.5V, Normal Mode. Typical values are

given for V_CC= V_L= 3.3V and T_A= 25°C, unless otherwise noted.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Maximum Data Rate

LTC2801, LTC2803 (Note 3)

l

R = 3kΩ, C = 2.5nF

100

250

kbps

L

R = 3kΩ, C = 1nF

L

LTC2802, LTC2804 (Note 3)

R = 3kΩ, C = 2.5nF

l

100

250

1000

kbps

L

R = 3kΩ, C = 1nF

L

R = 3kΩ, C = 250pF

L

Driver

SR(D)

Driver Slew Rate

LTC2801, LTC2803 (Figure 1)

l

V

= V = 1.8V, R = 3kΩ, C = 2.5nF

4

V/μs

CC

L

= V = 5.5V, R = 3kΩ, C = 50pF

30

L

LTC2802, LTC2804 (Figure 1)

l

V

= V = 1.8V, R = 3kΩ, C = 2.5nF

V/μs

CC

L

= V = 5.5V, R = 3kΩ, C = 50pF

150

L

t

, t

Driver Propagation Delay

Driver Skew

R = 3kΩ, C = 50pF (Figure 2)

PHLD PLHD

L

l

1

2

0.5

μs

LTC2801, LTC2803

0.2

LTC2802, LTC2804

ns

R = 3kΩ, C = 50pF (Figure 2)

SKEWD

L

100

50

LTC2801, LTC2803

LTC2802, LTC2804

l

t

, t

Driver Output Enable Time

Driver Output Disable Time

0.6

2

μs

PS = V , MODE = ↑, R = 3kΩ, C = 50pF

PZHD PZLD

L

(Figure 4)

, t

0.3

PS = V , MODE = ↓, R = 3kΩ, C = 50pF

PHZD PLZD

L

(Figure 4)

Receiver

l

t

, t

Receiver Propagation Delay

Receiver Skew

C = 150pF (Figure 3)

0.2

50

60

5

0.4

μs

ns

μs

PHLR PLHR

L

C = 150pF (Figure 3)

L

SKEWR

l

, t

Receiver Rise or Fall Time

Shutdown to Receiver Output Enable

C = 150pF (Figure 3)

L

200

15

RR FR

, t

PS = MODE = ↑ or ON/OFF = ↑,

R = 1kΩ, C = 150pF (Figure 5)

PZHR PZLR

L

l

t

, t

Receiver Output Disable upon Shutdown

0.15

0.3

μs

PS = MODE = ↓ or ON/OFF = ↓,

R = 1kΩ, C = 150pF (Figure 5)

PHZR PLZR

L

Power Supply Generator

/V Supply Rise Time

V

(Notes 3 and 4)

0.2

2

ms

DD EE

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 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 4: Time from PS ↑ or ON/OFF ↑ until V ≥ 5V and V

≤ –5V.

DD

EE

2801234fc

4

LTC2801/LTC2802/

LTC2803/LTC2804

TEST CIRCUITS

TOUT

V

L

TIN

0V

R

C

t

TLH

TIN

L

THL

V

OHD

3V

–3V

3V

–3V

TOUT

V

OLD

6V

2801F02

SR(D) =

t

or t

TIN t , t ≤ 40ns

THL

TLH

r

f

Figure 1. Driver Slew Rate Measurement

TOUT

V

L

TIN

1/2 V

L

0V

R

L

C

t

TIN

L

PHLD

PLHD

|

V

OHD

0V

TOUT

V

OLD

t

= |t

– t

2801F02

SKEWD

PHLD PLHD

TIN t , t ≤ 40ns

r

f

Figure 2. Driver Timing Measurement

ROUT

3V

RIN

1.5V

–3V

C

t

PLHR

RIN

L

PHLR

V

OHR

ROUT

1/2 V

L

V

OLR

t

= |t

– t

|

2801F03

SKEWR

PHLR PLHR

RIN t , t ≤ 40ns

r

f

Figure 3. Receiver Timing Measurement

V

L

MODE

1/2 V

L

0V

V

t

PHZD

PZHD

0 OR V

TOUT

L

OHD

5V

V

– 0.5V

+ 0.5V

OHD

TOUT

0V

R

C

t

PLZD

MODE

L

PZLD

V

–5V

OLD

V

OLD

2801F04

MODE t , t ≤ 40ns

r

f

Figure 4. Driver Enable/Disable Times

2801234fc

5

LTC2801/LTC2802/

LTC2803/LTC2804

TEST CIRCUITS

GND

V

L

V

L

PS AND MODE

1/2 V

L

R

L

0V

t

PHZR

PZHR

–3V OR 3V

ROUT

V

OHR

V

– 0.5V

OHR

ROUT

1/2 V

L

0V

C

t

PLZR

PS AND MODE

L

PZLR

V

L

1/2 V

L

V

+ 0.5V

OLR

2801F05

PS AND MODE t , t ≤ 40ns

r

f

Figure 5. Receiver Enable/Disable Times

TYPICAL PERFORMANCE CHARACTERISTICS ^T_A^{= 25°C, V}_CC= V_L= 3.3V unless otherwise noted.

Drivers Disabled Mode Supply

Current vs Supply Voltage

LTC2803 at 1.8V and 250kbps

LTC2804 at 1.8V and 1Mbps

3.0

2.5

2.0

1.5

1.0

0.5

0

V

= V

L

CC

T

= 85°C

= 25°C

= –40°C

T1IN

A

2V/DIV

T1OUT

T2OUT

T1OUT

T2OUT

T

A

10V/DIV

R1OUT

R2OUT

R1OUT

R2OUT

2V/DIV

V

= V = 1.8V

2μs/DIV

V

= V = 1.8V 400ns/DIV

1

2

3

4

5

6

CC

L

CC L

WRAPPING DATA

SUPPLY VOLTAGE (V)

TOUT LOAD = 1nF + RIN

ROUT LOAD = 150pF

TOUT LOAD = 250pF + RIN

ROUT LOAD = 150pF

2801 G01

2801 G02

2801 G03

Supply Current vs Supply Voltage

(Dual Transceiver)

Supply Current vs Load

Supply Current vs Data Rate

Capacitance (Dual Transceiver)

100

80

60

40

20

0

60

50

40

30

20

10

0

100

80

60

40

20

0

ALL DRIVERS SWITCHING

V

= V = 1.8V

CC

L

250kbps

125kbps

V

= V

CC

L

R

= 3k

R

= 3k

250kbps

C

= 1nF

1nF

125kbps

250pF

20.8kbps

250pF

V

= V = 1.8V

L

CC

LTC2804

LTC2802

LTC2804

LTC2803

LTC2804

LTC2803

R

= 3k

L

ALL DRIVERS SWITCHING

0

200

400

600

800

1000

1

2

3

4

5

6

2

3

4

1

5

SUPPLY VOLTAGE (V)

DATA RATE (kbps)

LOAD CAPACITANCE (nF)

2801 G05

2801 G04

2801 G06

2801234fc

6

LTC2801/LTC2802/

LTC2803/LTC2804

TYPICAL PERFORMANCE CHARACTERISTICS ^T_A^{= 25°C, V}_CC= V_L= 3.3V unless otherwise noted.

Receiver Output Voltage

vs Load Current

Receiver Input Threshold

vs Temperature

Receiver Output Duty Cycle

100

80

60

40

20

0

3.0

2.5

2.0

1.5

1.0

0.5

0

6

5

4

3

2

1

0

R

L

=

3V

V

= 5.5V

= 3.3V

= 1.8V

V

= 5.5V

= 3.3V

= 1.8V

IN

L

C

= 150pF

RECEIVERS

ALIVE MODE

INPUT HIGH

NORMAL

MODE

INPUT LOW

V

= 5.5V

= 3.3V

= 1.8V

L

0

1

2

3

4

5

6

7

8

10

100

1000

10000

50

TEMPERATURE (°C)

100 125

–50 –25

0

25

75

LOAD CURRENT (mA)

DATA RATE (kbps)

2801 GO9

2801 GO8

2801 GO7

Driver Slew Rate

Driver Short-Circuit Current

vs Temperature

Shutdown or Drivers Disabled Mode

Driver Leakage vs Temperature

vs Load Capacitance

–6

10

60

50

40

30

20

10

0

80

70

60

50

40

30

20

10

0

FALLING (LTC2802/04)

RISING (LTC2802/04)

FALLING (LTC2801/03)

RISING (LTC2801/03)

–7

–8

–9

10

SINKING

V(TOUT) = 15V OR

V(TOUT) = –15V

SOURCING

–10

10

REGULATOR CAN

LIMIT FURTHER

–11

50

TEMPERATURE (°C)

100 125

–50

25

50

75

100 125

–50 –25

0

25

75

–25

0

1

2

4

3

0

5

TEMPERATURE (°C)

LOAD CAPACITANCE (nF)

2801 G12

2801 G11

2801 G10

Logic Input Threshold

vs V_LSupply Voltage

LTC2804 Driver Outputs Exiting

Shutdown

LTC2804 Driver Outputs

Enable/Disable

3.0

2.5

2.0

1.5

1.0

0.5

0

T

A

= 85°C

= 25°C

= –40°C

A

T

2V/DIV

5V/DIV

2V/DIV

5V/DIV

MODE AND PS

MODE

INPUT HIGH

T1OUT

T2OUT

T1OUT

T2OUT

INPUT LOW

100μs/DIV

2μs/DIV

1

2

3

4

5

6

V

= 3.3V

V

= 3.3V

CC

L

= 1.8V

L

V

SUPPLY VOLTAGE (V)

L

LOAD = 3k + 2.5nF

LOAD = 3k + 250nF

2801 G13

2801 G14

2801 G15

2801234fc

7

LTC2801/LTC2802/

LTC2803/LTC2804

PIN FUNCTIONS

PIN NUMBER

2801

2802

2803

2804

2803-1

2804-1 COMMENTS

PIN NAME

V

CC

V

DD

3

4

5

6

5

6

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

and GND.

V

DD

V

EE

13*

17*

9

Generated Negative Supply Voltage for RS-232 Driver (–6.3V). Connect a 1μF capacitor

between V and GND.

EE

SW

5

6

7

8

9

7

8

Switch Pin. Connect a 10μH inductor between SW and V

Ground.

.

CC

GND

CAP

10

Charge Pump Capacitor for Generated Negative Supply Voltage. Connect a 220nF capacitor

between CAP and SW.

V

L

10

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 V

.

CC

TIN (T1IN, T2IN)

11

2

14, 13

3, 4

14, 13 Driver Input(s), referenced to V .

L

TOUT (T1OUT, T2OUT)

RIN (R1IN, R2IN)

3, 4

1, 2

RS-232 Driver Output(s).

RS-232 Receiver Input(s). Includes internal 5kΩ termination resistor(s).

1

1, 2

ROUT (R1OUT, R2OUT)

12

16, 15

16, 15 Receiver Output(s), referenced to V . Output is short-circuit protected to GND/V /V , and is

L

CC

L

high impedance in Shutdown mode, allowing data line sharing.

PS

8

9

10

11

—

11

Power Supply control pin, referenced to V . Enables the integrated DC-DC converter.

L

MODE

ON/OFF

Mode control pin, referenced to V . See Table 1 for functionality.

L

—

Transceiver enable pin, referenced to V . A logic low puts the device in Shutdown mode and

L

places both driver and receiver outputs in a high impedance state.

*Backside thermal pad

MODE CONTROL

Table 1. LTC2801-LTC2804

RECEIVER

DRIVER

MODE NAME

PS

L

MODE

OUTPUT(S)

DC-DC

OFF

OUTPUT(S)

I

*

I *

VL

VCC

SHUTDOWN

L

H

L

HI-Z

ON

HI-Z

1μA

RECEIVERS ACTIVE

DRIVERS DISABLED

L

OFF

15μA

H

ON

2.1mA

80μA OR

150μA

NORMAL

H

ON

2.3mA

80μA OR

150μA

Table 2. LTC2803-1, LTC2804-1

RECEIVER

OUTPUTS

DRIVER

MODE NAME

SHUTDOWN

NORMAL

ON/OFF

DC-DC

OFF

OUTPUTS

I

*

I *

VL

VCC

L

HI-Z

ON

HI-Z

ON

1μA

2.3mA

1μA

H

ON

150μA

*Typical currents for static drivers. Normal mode currents are for unloaded outputs.

2801234fc

8

LTC2801/LTC2802/

LTC2803/LTC2804

FEATURE SUMMARY

FEATURE

2801

1 + 1

DE

l

2802

1 + 1

DE

l

2803

2 + 2

DHC

l

2803-1

2 + 2

GN

2804

2 + 2

DHC

l

2804-1

2 + 2

GN

DRIVERS and RECEIVERS

PACKAGE

l

1.8V - 5.5V OPERATION

l

1.8V - 5.5V LOGIC SUPPLY (V )

L

l

SHUTDOWN (1μA)

l

RECEIVER(S) ACTIVE (15μA)

DRIVER DISABLE

l

100kb/s for R = 3kΩ, C = 2.5nF

L

l

250kb/s for R = 3kΩ, C = 1nF

L

l

1Mb/s for R = 3kΩ, C = 250pF

L

BLOCK DIAGRAM

L1

10μH

C1

220nF

1.8V TO 5.5V

C4

1μF

V

SW

CAP

CC

V

DD

EE

V

L

1.8V TO 5.5V

BOOST

REGULATOR

C5

220nF

C3

1μF

C2

1μF

V

DD

L

T2IN

T1IN

T2OUT

T1OUT

**

V

L

GND

V

EE

R2OUT

R1OUT

R2IN

R1IN

5k

V

L

PS

LTC2801

LTC2802

LTC2803

LTC2804

**

LTC2803

LTC2804

LTC2803-1

LTC2804-1

GND

MODE

CONTROL

ON/OFF

LTC2803-1

LTC2804-1

2801BD

2801234fc

9

LTC2801/LTC2802/

LTC2803/LTC2804

APPLICATIONS INFORMATION

Overview

ANY VOLTAGE FROM

1.8V TO 5.5V

ANY VOLTAGE FROM

1.8V TO 5.5V

The LTC2801 family of RS-232 transceivers operates on

V

CC

a V supply of 1.8V to 5.5V, utilizing a switching regula-

CC

V

L

tor to generate the necessary higher voltage rails for the

drivers. The transceivers interface with logic operating

EXTERNAL

DEVICE

RS-232

on any supply from 1.8V to 5.5V, independent of the V

CC

voltage. Depending on the device, one or two control pins

are available to invoke Shutdown, Receiver Active and

Driver Disable features.

2801F07

Figure 7. V_CCand V_LAre Independent

DC-DC Converter

Power-Saving Modes

The on-chip DC-DC converter operates from the V

CC

input, generating a 7V V supply and a charge pumped

WhentheDC-DCconverteranddriversareturnedoff(PSor

DD

–6.3V V supply, as shown in Figure 6. V and V

ON/OFF=logiclow), V supplycurrentisreducedto1μA.

EE

DD

EE

CC

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.

Tables 1 and 2 summarize the modes for each device.

In Shutdown mode, V supply current is reduced to 1μA,

L

and both receiver and driver outputs assume a high im-

pedance state.

In Receivers Active mode, the quiescent V supply current

L

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.

L1

10μH

C1

220nF

Half-Duplex Operation

1.8V TO 5.5V

C4

CAP

When the DC-DC converter is kept on (PS = logic high),

MODEservesasalow-latencydriverenableforhalf-duplex

operation. Each driver is enabled and disabled in less than

2μs, whileeachreceiverremainscontinuouslyactive. This

mode of operation is illustrated in Figures 15-17.

V

SW

CC

1μF

V

DD

EE

C2

1μF

V

L

1.8V TO 5.5V

BOOST

REGULATOR

C5*

220nF

C3

1μF

Battery Operation

2801F06

*OMIT IF V IS CONNECTED TO V

CC

L

To maximize battery life, connect V (and L1) directly to

CC

the unregulated battery voltage and V to the regulated

L

Figure 6. DC/DC Converter and Recommended Bypassing

supply, as shown in Figure 22. This conﬁguration typically

minimizes conversion loss while providing compatibility

with system logic levels.

V Logic Supply

L

AseparatelogicsupplypinV allowstheLTC2801familyto

L

interfacewithanylogicsignalfrom1.8Vto5.5V, asshown

in Figure 7. Simply connect the desired logic supply to

V . There is no interdependency between V and V ; they

Inductor Selection

A 10μH inductor with a saturation current (I ) rating

SAT

L

CC

L

of at least 200mA and low DCR (copper wire resistance)

is recommended. Some small inductors meeting these

requirements are listed in Table 3.

may simultaneously operate at any voltage from 1.8V to

5.5Vandsequenceinanyorder.IfV ispoweredseparately

L

from V , bypass V with a 220nF capacitor (C5).

CC

L

2801234fc

10

LTC2801/LTC2802/

LTC2803/LTC2804

APPLICATIONS INFORMATION

Table 3. Recommended Inductors

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.

PART

NUMBER

I

MAX DCR

(Ω)

SIZE

(mm)

SAT

(mA)

MANUFACTURER

LQH2MCN100K02L 225

1.2

0.85

1.1

Murata

2 × 1.6 × 0.95

2 × 1.6 × 1.6

2.5 × 2 × 1.6

www.murata.com

LBC2016T100K

FSLB2520-100K

245

220

Taiyo Yuden

www.t-yuden.com

Board Layout

Toko

www.tokoam.com

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

recommendedbecausetheirESRislowandtheyretaintheir

capacitance over relatively wide voltage and temperature

ranges. Use a voltage rating of at least 10V.

C1

GND

C2

V

L1

V

L

Table 4. Recommended Ceramic Capacitor Manufacturers

C5

GND

MANUFACTURER

Murata

URL

CC

GND

www.murata.com

www.tdk.com

www.t-yuden.com

www.avxcorp.com

www.kemet.com

C4

TDK

Taiyo Yuden

AVX

GND

TOP VIEW

= VIA

C3

Kemet

Inrush Current and Supply Overshoot Precaution

In certain applications, such as battery-operated and

wall-adapter devices, fast supply slew rates are generated

C1

GND

when power is connected. If V ’s voltage is greater than

CC

C2

L1

4.5V and its rise time is faster than 10μs, the pins V

DD

V

L

C5

and SW can exceed their ABS MAX values during start-

up. When supply voltage is applied to V , the voltage

GND

V

CC

GND

difference between V and V generates inrush current

CC

DD

C4

L1

10μH

C1

220nF

4.5V TO 5.5V

INRUSH

CURRENT

R1

SW

CAP

GND

1Ω

1/8W

V

CC

C3

C4

1μF

V

DD

GND

C2

1μF

TOP VIEW

= VIA

SCALE R1 WITH C1, C2, 1/C4

2801F08

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

V

CC

L

5

V

CC

L

LTC2804

LTC2803

12

11

10

13

14

15

16

1.8V TO 5.5V

CELL PHONE

10 PS

MODE

11 MODE

V

BATT

PERIPHERAL

PS

RA ON

T2IN

4

3

2

1

13

14

15

16

T2OUT

T1OUT

R2IN

T2IN

4

3

2

1

T2OUT

T1OUT

R2IN

RTS

TD

RTS

T1IN

TD

CTS

RD

R2OUT

R1OUT

R2OUT

R1OUT

CTS

RD

R1IN

GND

8

GND

8

2801F10

2801F11

Figure 10. Power-Saving Receivers-Active Mode

Figure 11. Cellphone Peripheral Interface

5V

3

3V

1.8V TO 5.5V

5

3

10

8

V

1.8V

5V

μP

CC

LTC2801

LTC2802

LTC2804-1

10

8

12

V

L

PS

9

11

13

14

15

16

MODE

ON/OFF

OFF ON

μP

T2IN

4

3

2

1

T2OUT

T1OUT

R2IN

TIN

TOUT

2

1

TIN

TOUT

2

1

T1IN

11

12

11

12

R2OUT

R1OUT

ROUT

RIN

ROUT

RIN

R1IN

GND

6

GND

6

GND

2801F12

2801F13

2801F14

8

Figure 12. 1.8V Microprocessor Interface

Figure 13. 5V Microprocessor Interface

Figure 14. Power-Saving Shutdown Mode

1.8V TO 5.5V

5

3

V

CC

V

CC

LTC2803

LTC2802

12

10

V

L

V

L

V

L

10

8

PS

11

9

R T

MODE

T2IN

R T

MODE

R T

3.3k

MODE

13

15

14

16

T2OUT

R2IN

4

2

3

1

3.3k

R2OUT

T1IN

TIN

TOUT

2

1

TIN

TOUT

2

1

11

12

11

12

T1OUT

R1IN

3.3k

R1OUT

ROUT

RIN

ROUT

RIN

GND

2801F17

2801F15

2801F16

8

6

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

7

9

5

7

9

V

SW

V

SW

CC

L

CC

L

C1

470nF

LTC2803

12

4

3

13

14

C4

2μF

CAP

3k

C

L

T2IN

4

3

2

1

T2IN

4

3

2

1

13

14

15

16

T2OUT

T1OUT

R2IN

13

14

15

16

T2OUT

T1OUT

R2IN

2801F18

T1IN

DATA RATE

(kbps)

100

250

1000

R2OUT

R1OUT

R2OUT

R1OUT

C

(nF) LTC2803 LTC2804

L

5

2

X

R1IN

0.5

GND

8

V

GND

8

V

EE

DD

EE

DD

6

17

6

17

Figure 18. Driving Larger Loads

2801F19

C2

2μF

C3

2μF

ANY COMBINATION

LTC2801/LTC2802/LTC2803/LTC2804

Figure 19. Quad Transceiver (2.5V < V_CC< 5.5V)

1.8V TO 5.5V

12

C5

220nF

V

L

LTC2803

V

= 1.8V

CC

2

1

R2OUT 15

R1OUT 16

R2IN

DRIVERS DISABLED

3V TO 25V

–25V TO 0V

V

L

0V

V

CC

= 1.8V

DRIVERS LOADED

V

SW

11

5

10

5V/DIV

MODE

OFF ON

PS

V

= 5.5V

CC

DRIVERS DISABLED

13

V

T2IN

CC

7

14

V

= 5.5V

CC

SW

T1IN

DRIVERS LOADED

GND

V

EE

DD

200ns/DIV

2801F21

8

6

17

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

(I_L= 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)

7047 ± 70.7

4077 ±70.7

(ꢁ SIDES)

R = 70..3

TYP

ꢀ

.ꢁ

70ꢀ7 ±7073

R = 7073

TYP

±0±7 ±70.7

±0±7 ±7073

.0ꢀ7 ± 7073

±067 ±7073

ꢁ0ꢁ7 ±7073

±077 ±70.7

(ꢁ SIDES)

.0ꢀ7 ± 70.7

PIN .

PIN . NOTCH

TOP MARK

(NOTE 6)

R = 70ꢁ7 OR

70±3 × 43°

CHAMFER

(UE.ꢁ/DE.ꢁ) DFN 7876 REV

D

6

.

70ꢁ3 ± 7073

70ꢀ3 ±7073

70ꢁ77 REF

70ꢁ3 ± 7073

ꢁ037 REF

7037 BSC

PACKAGE OUTLINE

ꢁ037 REF

BOTTOM VIEW—EXPOSED PAD

7077 – 7073

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED

NOTE:

40 DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE

MOLD FLASH0 MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 70.3mm ON ANY SIDE

30 EXPOSED PAD SHALL BE SOLDER PLATED

60 SHADED AREA IS ONLY A REFERENCE FOR PIN . LOCATION

ON THE TOP AND BOTTOM OF PACKAGE

.0 DRAWING PROPOSED TO BE A VARIATION OF VERSION

(WGED) IN JEDEC PACKAGE OUTLINE M7-ꢁꢁ9

ꢁ0 DRAWING NOT TO SCALE

±0 ALL DIMENSIONS ARE IN MILLIMETERS

DHC Package

16-Lead Plastic DFN (5mm × 3mm)

(Reference LTC DWG # 05-08-1706)

R = 70..3

TYP

7047 ± 70.7

3077 ±70.7

(ꢁ SIDES)

9

.6

R = 70ꢁ7

TYP

7063 ±7073

±037 ±7073

±077 ±70.7 .063 ± 70.7

(ꢁ SIDES) (ꢁ SIDES)

.063 ±7073

PIN .

ꢁ0ꢁ7 ±7073 (ꢁ SIDES)

TOP MARK

(SEE NOTE 6)

PIN .

NOTCH

PACKAGE

OUTLINE

(DHC.6) DFN ..7±

8

.

70ꢁ3 ± 7073

70ꢀ3 ±7073

70ꢁ77 REF

70ꢁ3 ± 7073

7037 BSC

4047 ±70.7

4047 ±7073

(ꢁ SIDES)

7077 – 7073

BOTTOM VIEW—EXPOSED PAD

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

NOTE:

.0 DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJED-.) IN JEDEC

PACKAGE OUTLINE MO-ꢁꢁ9

ꢁ0 DRAWING NOT TO SCALE

±0 ALL DIMENSIONS ARE IN MILLIMETERS

40 DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE

MOLD FLASH0 MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 70.3mm ON ANY SIDE

30 EXPOSED PAD SHALL BE SOLDER PLATED

60 SHADED AREA IS ONLY A REFERENCE FOR PIN . LOCATION ON THE

TOP AND BOTTOM OF PACKAGE

2801234fc

14

LTC2801/LTC2802/

LTC2803/LTC2804

PACKAGE DESCRIPTION

GN Package

16-Lead Plastic SSOP (Narrow .150 Inch)

(Reference LTC DWG # 05-08-1641)

0.89 – 0.96*

(4087. – 409ꢀ8)

0743 ±0773

0779

(70ꢁꢁ9)

REF

.6 .3 .4 .± .ꢁ .. .7 9

0ꢁ34 MIN

0.37 – 0.63

0ꢁꢁ9 – 0ꢁ44

0.37 – 0.3ꢀ**

(308.ꢀ – 60.98)

(±08.7 – ±0988)

07.63 ±077.3

07ꢁ37 BSC

RECOMMENDED SOLDER PAD LAYOUT

.

ꢁ

±

4

3

6

ꢀ

8

07.3 ± 0774

(70±8 ± 70.7)

× 43°

073±ꢁ – 07688

(.0±3 – .0ꢀ3)

0774 – 07798

(70.7ꢁ – 70ꢁ49)

077ꢀ – 07798

(70.ꢀ8 – 70ꢁ49)

7° – 8° TYP

07.6 – 0737

(70476 – .0ꢁꢀ7)

07ꢁ37

(706±3)

BSC

0778 – 07.ꢁ

GN.6 (SSOP) 7ꢁ74

(70ꢁ7± – 70±73)

TYP

NOTE:

.0 CONTROLLING DIMENSION: INCHES

INCHES

ꢁ0 DIMENSIONS ARE IN

(MILLIMETERS)

±0 DRAWING NOT TO SCALE

*DIMENSION DOES NOT INCLUDE MOLD FLASH0 MOLD FLASH

SHALL NOT EXCEED 70776" (70.3ꢁmm) PER SIDE

**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH0 INTERLEAD

FLASH SHALL NOT EXCEED 707.7" (70ꢁ34mm) PER SIDE

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 representa-

tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

15

LTC2801/LTC2802/

LTC2803/LTC2804

TYPICAL APPLICATION

L1

10μH

C1

220nF

1.8V TO 5.5V

+

C4

1μF

*

–

7

9

SW

CAP

DC-DC

5

V

CC

1.8V TO 5.5V

12

LTC2804

L

C5

220nF

10

11

13

14

15

16

*

PS

V

CC

PP

MODE

T2IN

X

4

3

2

1

T2OUT

T1OUT

R2IN

CTS

RX

UART

RTS

Y

T1IN

TXD

μP

R2OUT

R1OUT

PP

Z

R1IN

TX

RXD

GND

8

V

EE

DD

6

2801F22

17

C2

1μF

C3

1μF

*ADDITIONAL BYPASS CAPACITOR AS NEEDED

Figure 22. Diagnostic Port Operating Directly Off Unregulated Battery Voltage

RELATED PARTS

PART NUMBER

LT1780/LT1781

LTC1337

DESCRIPTION

COMMENTS

2-Driver/2-Receiver RS232 Transceiver Single 5V Supply with 0.1ꢀF Capacitors, 15kV ESD

3-Driver/5-Receiver RS232 Transceiver Ultralow Power for DTE Applications

5-Driver/3-Receiver RS232 Transceiver Ultralow Power for DCE Applications

LTC1338

LT1039/LT1039-16 3-Driver/3-Receiver RS232 Transceiver 30kΩ Input Impedance for Multi-Drop Applications

LTC1348

3-Driver/5-Receiver RS232 Transceiver True RS232 Levels on 3.3V Supply

2801234fc

LT 0808 REV C • PRINTED IN USA

LinearTechnology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

16

●

(408) 432-1900 FAX: (408) 434-0507 www.linear.com


型号：	LTC2803CGN-1-PBF
厂家：	Linear
描述：	1.8V to 5.5V RS-232 Single and Dual Transceivers 1.8V至5.5V的RS - 232单通道和双通道收发器
文件：	总16页 (文件大小：386K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LTC2803CGN-1-PBF [Linear]

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