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dc1880af

DEMO MANUAL DC1880A

aDDitional information

VL Logic Supply

Table 1 lists several ways to supply power to the VL pin. 

Methods 1a/b/c are recommended for most purposes. 

Table 1. Recommended Options for Powering the VL Supply

METHOD

DC590 

JP6

DC1880A 

JP12

DC1880A 

JP11

SOURCE FOR  

VL POWER

1a 

1b 

1c

5V* 

3.3V 

OPEN (2.7V)

ON* 

ON* 

ON*

5V* 

3.3V 

OPEN (2.9V)

LDO or DC590 

LDO or DC590 

LDO or DC590

2

EXT

ON*

X**

LDO

3

EXT

OPEN

X**

DC1880A VL TURRET

4

5V* or 3.3V

OPEN

X**

DC590

* (Default) 

** Including OPEN (2.9V)

L+ Power Supply Outputs

Enable  the  L+  power  supply  outputs  by  setting  their 

respective EN_L+ register bits high.

CQ Line Driver Outputs

Enable the CQ line drivers either by input pin (using the 

TXEN turrets and/or jumpers JP1/3/7/9) or via the SPI 

interface (by setting DRVEN register bits high). See Table 2.

Table 2. CQ Driver Mode Configuration

JP1/3/7/9 

SETTING

TXEN 

TURRET

DRVEN  

BIT

CQ DRIVER 

MODE

GND 

VL 

EXT

L/H

0

OFF 

ON 

ON 

OFF/ON

Control the output CQ states using the TXD turrets and/

or jumpers JP2/4/8/10. See Table 3.

Table 3. CQ Driver Output Level Configuration

JP2/4/8/10 

SETTING

TXD 

TURRET

DRVEN  

BIT

CQ DRIVER 

MODE*

CQ 

LEVEL

GND 

GND/VL 

EXT 

DB9

L/H 

X

H/L**

OFF 

ON 

ON 

ON

H/L 

H/L 

H/L

* From Table 2 

** RS232 transceiver U2 inverts

Alternatively, operate the CQ drivers solely via the SPI 

interface by tying TXD low and controlling the DRVEN 

register bits. This method is suitable for SIO mode and 

switching at or below COM2 data rates (38.4kb/s).

TVS Protection

The CQ and L+ pins are protected by 36V TVS diodes for 

cable-driving applications.

Serial Port

A DB9 connector enables CQ data to be sent (for one or 

more ports) and received (for one port) using PC software 

such as a serial terminal program. Jumper JP5 enables 

the required RS-232 transceiver. 
Select the desired combination of drivers by setting one 

or more of JP2/4/8/10 to the DB9 position. Select one CQ 

receiver using JP6.

L+ Isolation

If L+ isolation is not needed, Schottky diodes D1-D4 may 

be replaced with 0Ω resistors.

Interrupts

The  LTC2874  includes  an  open-drain  interrupt  line  for 

signaling the host controller when it needs service. This 

signal is accessible on the DC1880A board at the 

IRQ

 test 

point. An LED is also included for convenience.

Summary of Contents for DC1880A

Page 1: ...respective owners Performance Summary Design files for this circuit board are available at http www linear com demo DC1880A Specifications are at TA 25 C VDD 24V and VL 3 3V SYMBOL PARAMETER CONDITION...

Page 2: ...2 dc1880af DEMO MANUAL DC1880A Quick Start Procedure Figure 1 Proper Setup...

Page 3: ...both boards to 5V b When using a Linduino One instead of a DC590 board set the DC1880A LDO to 5V JP11 5 0V or disable it JP12 OPEN 5 Before connecting the input power supply to the DC1880A board verif...

Page 4: ...See Table 3 Table 3 CQ Driver Output Level Configuration JP2 4 8 10 SETTING TXD TURRET DRVEN BIT CQ DRIVER MODE CQ LEVEL GND GND VL EXT DB9 X X L H X X X X H L OFF ON ON ON L H L H L H L From Table 2...

Page 5: ...mines which receiver output RXD1 2 3 4 if any is connected to the serial port Default position RXD1 JP5 COM PORT Enable Connects RS232 transceiver U2 to VL logic supply Default position ON JP11 VL Sel...

Page 6: ...LTC2874 registers to monitor status Connect Disconnect Button TheDisconnectbuttondisablestheSPIinterfaceandmost of the GUI The Connect button restarts SPI polling and activates the complete GUI Reset...

Page 7: ...7 dc1880af DEMO MANUAL DC1880A Using the DC1880A Software Figure 2 Main Window Ports Tab...

Page 8: ...8 dc1880af DEMO MANUAL DC1880A Using the DC1880A Software Figure 3 Main Window Timers and Globals Tab...

Page 9: ...9 dc1880af DEMO MANUAL DC1880A Using the DC1880A Software Figure 4 Main Window Events Tab Figure 5 Register Map Window...

Page 10: ...using USB A B cable 3 Problem LTC2874 not detected Error 2 Solution Ensure that the DC590 ribbon cable is con nected and that VL power is applied See Table 1 4 Problem Unsuccessful communication with...

Page 11: ...3A 0806 TAIYO YUDEN CBC2016T100M 9 9 R5 12 R24 RES 100 5 1206 AAC CR18 101JM 10 1 R22 RES 4 99k 1 0603 AAC CR16 4991FM 11 3 R13 15 RES 4 99k 1 0603 AAC CR16 4991FM 12 1 R16 RES 100k 1 0603 AAC CR16 10...

Page 12: ...2mm MOLEX 87831 1420 10 5 JP1 JP3 JP7 JP9 JP11 HEADER 2 3 2mm SAMTEC TMM 103 02 L D 11 5 JP2 JP4 JP6 JP8 JP10 HEADER 2 4 2mm SAMTEC TMM 104 02 L D 12 2 JP5 JP12 HEADER 1 2 2mm SAMTEC TMM 102 02 L S 1...

Page 13: ...ST PROTOTYPE KEITH B 9 17 12 N A J10 VDD 8V 30V LINE OUT Q2 FQT7N10 R27 0 2 0805 R2 10 Q1 FQT7N10 R25 0 2 0805 R1 10 Q4 FQT7N10 R26 0 2 0805 R4 10 Q3 FQT7N10 R28 0 2 0805 R3 10 J11 GND 2 4 6 8 10 12 1...

Page 14: ...DING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE EXCEPT TO THE EXTENT OF THIS INDEMNITY NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT SPECIAL INCIDENTAL OR CONS...

Page 15: ...Mouser Electronics Authorized Distributor Click to View Pricing Inventory Delivery Lifecycle Information Analog Devices Inc DC1880A...

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