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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 598

EVALUATION CARD FOR THE LTC2051 IN THE DFN PACKAGE

LTC2051CDD

DESCRIPTION

Demonstration circuit 598 simplifies the evaluation of

the LTC2051CDD op amp in the tiny, 3mm

3mm, DFN

(

ual in-line,

lat,

o-leads) chip-scale package. Electri-

cal performance of this LTC2051 is the same as previous

versions. This version is only a packaging enhancement.

An evaluation circuit can easily be built on this board

without handling the tiny DFN device. Pads are provided

for adding external components and holes are available

for jumpers, signal I/O and supply wires. Supply bypass

capacitors are already on the board. Alternatively adding

two 4-pin headers (0.1" spacing) converts the board to a

standard 8-pin DIP format for use with a socket on a

second circuit board.

The backside of this evaluation board is void of metal to

allow wiring into an existing system with the board rest-

ing on top of other components.

About the LTC2051CDD

The LTC2051 is a Precision Dual, Zero-Drift Op Amp



Maximum Input Offset Voltage of 3



Maximum Offset Voltage Drift of 30nV/



750

A Supply Current per Amplifier, 25mA Output

Current



Low Noise, 1.5

P–P

(0.01Hz to 10Hz)



No Supply Sequencing Problems



Output Swings to Within 2mV of V

–

and 20mV of V



7.5KHz Internal Sampling Frequency



Total Supply Voltage Range: 2.7V to 11V

Table 1.

Typical Performance Summary (Single 3V Supply, T

=25

C) Visit www.linear.com for complete data sheet.

PARAMETER CONDITION VALUE

Common Mode Input Voltage Range 0V to 1.7V

Supply Current Per Amplifier 750

Offset Voltage 3

Input Bias Current

8pA

Open Loop Voltage Gain 140dB

CMRR and PSRR 135dB

Gain Bandwidth Product 3MHz

Slew Rate 2 V/

sec

Device Top Mark Identifier: LAAN

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 598

EVALUATION CARD FOR THE LTC2051 IN THE DFN PACKAGE

QUICK START PROCEDURE

Build the evaluation circuit in one of two ways as shown in Figures 1 and 2.

OUT

GND

LA xx

Figure 1.

External Components Directly on the PCB (0.1•F Bypass Capacitors: AVX 1206C104KAT). Example connections shown may not

be correct for this device.

GROUND WIRE

FOR BYPASS CAPS

DFN

PACKAGE

TEST

BOARD

DEMONSTRATION

CIRCUIT

8-PIN DIP

SOCKET

HEADER: MILL-MAX

3402-0-00-21-00-00-03-0

Figure 2.

Convert the Board to an 8-pin DIP Format

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 598

EVALUATION CARD FOR THE LTC2051 IN THE DFN PACKAGE

PACKAGE AND CONNECTION DRAWING

3.00 ±0.10

(4 SIDES)

NOTE:

1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)

2. ALL DIMENSIONS ARE IN MILLIMETERS

3. 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

4. EXPOSED PAD SHALL BE SOLDER PLATED

0.38 ± 0.10

BOTTOM VIEW—EXPOSED PAD

1.65 ± 0.10

(2 SIDES)

0.75 ±0.05

R = 0.115

TYP

2.38 ±0.10

(2 SIDES)

PIN 1

TOP MARK

0.200 REF

0.00 – 0.05

(DD8) DFN 0902

0.28 ± 0.05

2.38 ±0.05

(2 SIDES)

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

1.65 ±0.05

(2 SIDES)2.25 ±0.05

0.50

BSC

0.58 ±0.05

3.35 ±0.05

PACKAGE

OUTLINE

0.28 ± 0.05

0.50 BSC

TOP VIEW

DD PACKAGE

8-LEAD (3mm × 3mm) PLASTIC DFN

1OUT A

–IN A

+IN A

–

OUT B

–IN B

+IN B

ASSEMBLY TIPS

−

Activation temperature 130

C to 150

C Following are the recommended procedures for solder-

ing surface mount packages to PC boards.

−

Reflow begins at 183

C (63Sn/37Pb)



Reflow Soldering with Solder Paste

−

Time above 183

C for 30 seconds

•

Use of solder plated boards is recommended.

−

Peak package body temperature 220

C to 245

•

Screen solder paste on board.

−

Dwell time at peak temperature 10 seconds max

•

Mount components on board.

−

Cooling rate 2

C to 4

C per second

•

Infrared or forced hot air convection reflow is rec-

ommended for best performance. Parameters:

−

Clean boards.

•

For Vapor Phase Reflow, recommended parameter

ranges for:

−

Preheat peak temperature 125

C and 2

to 4

C per second rise

−

Heating rate: 4

C per second max

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 598

EVALUATION CARD FOR THE LTC2051 IN THE DFN PACKAGE

−

Preheat temperature: 45

C to 80

−

Time above 200

C: 50 seconds to 90 seconds

−

Peak package temperature: 212

C to 219



Wave Soldering and Hand Soldering are not recom-

mended.

REWORK GUIDELINES FOR DFN PACKAGES

Each package mounting site should be reworked one at a

time only, to ensure maximum quality and reliability.

Linear Technology has found the following rework pro-

cedure to be effective with DFN packages but by no

means excludes other methods more suited to specific

manufacturing needs.



Reflow Temperature Profile

Each package site to be reworked should be individu-

ally heated. The reflow temperature profile can be es-

tablished using a hot gas tool and a thermocouple

embedded in the solder joints of a sample setup unit

on the PCB.



Preheating and Package Removal

A package rework tool with vacuum pickup similar to

the A.P.E. Flo-Master can be used. A bottom PCB

heater is required to provide preheating of the PCB to

approximately 110°C to 120°C. The rework nozzle

must be centered with respect to the package in order

to direct the hot gas flow over the top of the package

while limiting the temperature of the adjacent compo-

nents to prevent solder reflow.



Site Rework

With a combination on hot gas/vacuum desoldering

tool and solder wick ribbons (if necessary), remove

the package and any remaining solder residues. Use a

minimal amount of flux if it is required to remove sol-

der residue. This will also assist in leaving a smooth,

flat surface for the reattachment of a replacement

unit. The site for the package should be thoroughly

cleaned with isopropyl alcohol (IPA) and dried with

clean dry air (CDA).



Solder Paste Application

Solder paste may be screen printed on to the package

landing site and exposed heat sink pads. Stainless

steel stencils are recommended for solder paste ap-

plication. The printed solder deposits should be 100

percent inspected for uniformity of size and shape.

Some applications may have severe space constraints

preventing screen printing to be accomplished on the

PCB. Therefore, solder paste can be directly applied to

the packages landing site and exposed heatsink pad.

The package is to be picked and placed using a vision

aided system similar to the A.P.E. Sniper SMD 7007

Rework System.



Reflow Process

The replacement package, once it has been placed

onto the reworked PCB landing site, should be re-

flowed on the PCB using a hot gas tool on the top of

the package and a heater on the bottom of the PCB.

The reflow temperature should not exceed 240°C.

Note that liquidus temperature for 63/37 Sn/Pb solder

is 183°C. Make sure to limit adjacent components to

below the solder reflow temperature. The solder paste

manufacturer’s recommended reflow temperature

profile/specifications must be complied with to avoid

damage to the PCB and/or adjacent components. A

100 percent post rework visual inspection for good

joint wetting is recommended.