Rainbow Electronics MAX9890 - Manual (Page 9)

External Capacitor (C
CEXT
)
The external click-pop suppression capacitor at CEXT
serves a dual purpose. On power-up, C
CEXT
is
charged by an internal current source and is used to
slowly ramp up the external coupling capacitors. When
the device is powered down, C
CEXT powers the internal
circuitry used to drain the external coupling capacitors.
A 0.1µF capacitor between CEXT and GND provides
clickless/popless operation with coupling capacitors for
both the MAX9890A and MAX9890B, even with the
rapid removal of supply voltage.
Applications Information
Layout
Good layout improves performance by decreasing the
amount of stray capacitance and noise. To decrease
stray capacitance, minimize PC board trace lengths
and resistor leads, and place external components as
close to the device as possible.
Power Supply and Bypassing
The excellent PSRR of the MAX9890 allows it to operate
from noisy power supplies. In most applications, a
0.1µF capacitor from V
CC to GND is sufficient. This
bypass capacitor should be placed close to V
CC
.
UCSP Applications Information
For the latest application details on UCSP construction,
dimensions, tape-carrier information, printed circuit
board techniques, bump-pad layout, and recommend-
ed reflow temperature profile, as well as the latest infor-
mation on reliability testing results, refer to the
Application Note, “UCSP—A Wafer-Level Chip-Scale
Package” available on Maxim’s website at www.maxim-
ic.com/ucsp.
Chip Information
TRANSISTOR COUNT: 1001
PROCESS: BiCMOS
MAX9890
Audio Click-Pop Suppressor
_______________________________________________________________________________________ 9
0
-30
10 100 1k 10k 100k
LOW-FREQUENCY ROLLOFF
(R L = 16 Ω)
-24
-27
-12
-15
-18
-21
-6
-9
-3
FREQUENCY (Hz)
ATTENUATION (dB)
330 µF
220 µF
100 µF
33 µF
Figure 7. Low-Frequency Attenuation for Common DC-Blocking
Capacitor Values
CAPACITOR
SIZE (µF)
MAX9890A
TURN-ON TIME
(200ms)
MAX9890B
TURN-ON TIME
(300ms)
33 √ √
47 √ √
100 √ √
150 * √
220 * √
330 — *
470 — *
Table 1. Coupling Capacitor
*May experience some degradation of click-pop suppression.