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dc1733af

DEMO MANUAL DC1733A

DESCRIPTION

LT3669

Industrial Transceiver with Integrated

Step-Down Regulator and LDO

Demonstration circuit 1733A is an industrial transceiver

withintegratedstep-downregulatorandLDOfeaturingthe

LT®3669.Theboardoperatesfrom7.5Vto40VwhenJP7is

set to L+. When the JP7 is set to RES, the minimum input

voltage is 16.5V. The board withstands transients up to

60V.Thestep-downregulatoroutputis5V.TheLDOoutput

is 3.3V. There are two assembly versions. DC1733A-A is

for the LT3669 and DC1733A-B is for the LT3669-2. The

difference is the LT3669 has an integrated catch diode.

The LT3669-2 requires an external catch diode. Table 1

shows the differences between the two versions.

L

, LTC, LTM, LT, Burst Mode are registered trademarks of Linear Technology Corporation.

Other product names may be trademarks of the companies that manufacture the products..

PERFORMANCE SUMMARY

The board also provides various interfaces for line drivers

and receivers. JP8 to JP11 set the signal sources or levels

for TXEN1, TXEN2, TXD1 and TXD2.

The LT3669 data sheet gives complete descriptions of the

part,operationandapplicationinformation.Thedatasheet

must be read in conjunction with this quick start guide for

working on or modifying the demo circuit 1733A.

Design files for this circuit board are available.

Call the LTC Factory.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

L+

Input Supply

7.5

40

V

Output Voltage

Step-Down Regulator

4.75

5

5.25

V

Output Voltage

LDO

3.135

3.3

3.465

V

Maximum Buck Output Current

100

mA

300

mA

Maximum LDO Output Current

LT3669, VLDO = 3.3V

100

mA

LT3669-2, VLDO = 3.3V

150

mA

FSW

Switching Frequency

600

kHz

EFF

Efficiency

65

%

76

%

TRST

Reset Timeout Period

C5=100nF

12.5

ms

Table 1. Version Table

ASSY TYPE

U1

C8

C9

D6

L1

DC1733A-A

LT3669EUFD

0.1A

0.1A

10µF

0.1µF

OPEN

82µH, CDRH4D22HPNP-820MC

DC1733A-B

LT3669EUFD-2

0.15A

0.3A

22µF

0.22µF

DFLS160

33µH, CDRH50D28RNP-330MC