Rainbow Electronics MAX107 - Manual (Page 18)

MAX107
Dual, 6-Bit, 400Msps ADC with On-Chip,
Wideband Input Amplifier
18 ______________________________________________________________________________________
tion-case (
θjc) resistance of ≈1.26°C/W. In this pack-
age, the data converter die is attached to an exposed
pad (EP) leadframe using a thermally conductive
epoxy. The package is molded in a way, that this lead-
frame is exposed at the surface, facing the printed cir-
cuit board (PC board) side of the package (Figure 10).
This allows the package to be attached to the PC board
with standard infrared (IR) flow soldering techniques. A
specially created land pattern on the PC board, match-
ing the size of the EP (7.5mm x 7.5mm) does not only
guarantee proper attachment of the chip, but can also
be used for heat-sinking purposes. Designing thermal
vias* into the land area and implementing large ground
planes in the PC board design, further enhance the
thermal conductivity between board and package. To
remove heat from an 80-pin TQFP package efficiently,
an array of 6 x 6 vias (
≤0.3mm diameter per via hole
and 1.2mm pitch between via holes) is required.
Note: Efficient thermal management for the MAX107 is
strongly depending on PC board and circuit design,
component placement, and installation. Therefore,
exact performance figures cannot be provided.
However, the MAX105EV kit exhibits a typical
θ
ja
of
18°C/W. For more information on proper design tech-
niques and recommendations to enhance the thermal
performance of parts such as the MAX107, please refer
to Amkor Technology’s website at www.amkor.com.
Static Parameter Definitions
Integral Nonlinearity (INL)
Integral nonlinearity is the deviation of the values on an
actual transfer function from a straight line. This straight
line is drawn between the endpoints of the transfer
function, once offset and gain errors have been nulli-
fied. The static linearity parameters for the MAX107 are
measured using the sine-histogram method.
Differential Nonlinearity (DNL)
Differential nonlinearity is the difference between an
actual step-width and the ideal value of 1LSB. A DNL
error specification of greater than -1LSB guarantees no
missing codes and a monotonic transfer function.
Dynamic Parameter Definitions
Aperture Jitter and Delay
Aperture uncertainties affect the dynamic performance
of high-speed converters. Aperture jitter, in particular,
directly influences SNR and limits the maximum slew
rate (dV/dt) that can be digitized without significant
error. Aperture jitter limits the SNR performance of the
ADC according to the following relationship:
SNR dB = 20 x log
10
[1 / (2 x π x f
IN x t AJ[RMS] )],
where f IN represents the analog input frequency and
t AJ is the RMS aperture jitter. The MAX107’s innovative
DIE
COPPER TRACE, 1oz.
TOP LAYER
GROUND PLANE (AGND)
GROUND PLANE
AGND, DGND
POWER PLANE
THERMAL LAND
COPPER PLANE, 1oz.
6 x 6 ARRAY OF THERMAL VIAS
THERMAL LAND
COPPER PLANE, 1oz.
EXPOSED PAD
EXPOXY
BONDING WIRE
80-PIN TQFP PACKAGE
WITH EXPOSED PAD
COPPER
TRACE, 1oz.
PC BOARD
Figure 10. MAX107 Exposed Pad Package Cross-Section
*Connects the land pattern to internal or external copper planes.