
MAX4908/MAX4909/MAX4930/MAX4932
Detailed Description
The MAX4908/MAX4909/MAX4930/MAX4932 dual 3:1
clickless audio multiplexers are low 0.38Ω (typ) on-resis-
tance, low 150nA (typ) supply current, high power-sup-
ply rejection ratio (PSRR) devices that operate from a
+1.8V to +5.5V single supply. These devices feature a
negative signal capability that allows signals below GND
to pass through without distortion and break-before-
make switching.
The MAX4908/MAX4909/MAX4930/MAX4932 use two
digital control bits CB1 and CB2 to switch between sig-
nals (see Table 1). The MAX4908 has shunt resistors on
all the unselected terminals to suppress click-and-pop
sounds that may occur from switching to a pre-charged
terminal. The MAX4909 does not have click-and-pop
suppression resistors on X0 and Y0 terminals for appli-
cations that do not require predischarge switching. The
MAX4930 only has shunt resistors on X2 and Y2 termi-
nals. The MAX4932 has no shunt resistors on all termi-
nals.
Applications Information
Digital Control Inputs
The MAX4908/MAX4909/MAX4930/MAX4932 logic
inputs accept up to +5.5V regardless of supply voltage.
For example, with a +3.3V supply, CB_ can be driven
low to GND and high to +5.5V, allowing for mixing of
logic levels in a system. Driving CB_ rail-to-rail mini-
mizes power consumption. For a +3.3V supply voltage,
the logic thresholds are +0.5V (low) and +1.4V (high).
Analog Signal Levels
The MAX4908/MAX4909/MAX4930/MAX4932 have a low
on-resistance of 0.38Ω (typ) and the on-resistance flat-
ness is guaranteed over temperature and will show
minimal variation over the entire voltage supply range
(see the
Typical Operating Characteristics). The on-
resistance flatness and low-leakage features make it
ideal for bidirectional operation. The switches are bidi-
rectional, so X_, Y_, and common terminals X and Y
pins can be either inputs or outputs.
These devices pass signals as low as VCC - 5.5V,
including signals below ground with minimal distortion.
Dual 3:1 Clickless Audio Multiplexers
with Negative-Signal Handling
6
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Table 1. Truth Table
CB1
CB2
COMMON X
COMMON Y
0
High Impedance
0
1
Connected to X0
Connected to Y0
1
0
Connected to X1
Connected to Y1
1
Connected to X2
Connected to Y2
Pin Description
PIN
TDFN-EP
WLP
NAME
FUNCTION
1B4
VCC
Positive Supply Voltage Input
2
C4
X
Analog Output X Common Terminal
3,10
—
N.C.
No Connection. Not internally connected.
4
C3
X2
Analog Input X2
5
C2
X1
Analog Input X1
6
B2
CB1
Digital Control Input 1
7
C1
X0
Analog Input X0
8
B1
GND
Ground
9
A1
Y0
Analog Input Y0
11
A2
Y1
Analog Input Y1
12
A3
Y2
Analog Input Y2
13
B3
CB2
Digital Control Input 2
14
A4
Y
Analog Output Y Common Terminal
—
EP
Exposed Pad. Connect to ground or leave unconnected.