Datasheet

LTC6421-20
7
642120fb
PIN FUNCTIONS
+INA, –INA, –INB, +INB (Pins 1, 2, 5, 6): Differential
Inputs of A and B channel respectively.
V
–
(Pins 3, 4, 13, 14, 21): Negative Power Supply. All
four pins, as well as the exposed back, must be connected
to same voltage/ground.
ENABLEA, ENABLEB (Pins 9, 18): Logic inputs. If low,
the amplifi er is enabled. If high, the amplifi er is disabled
and placed in a low-power shutdown mode, making
the amplifi er outputs high impedance. These pins are
internally separate. These pins should not be left
fl oating.
V
+
A , V
+
B (Pins 15, 20, 7, 12 ): Positive Power Supply
(Normally tied to 3V or 3.3V). Supply pins of A and B channels
are internally separate. Bypass each pin with 1000pF and
0.1μF capacitors as close to the pins as possible.
–OUTA, +OUTA, –OUTB, +OUTB (Pins 16, 17, 11, 10):
Differential Outputs of channels A and B respectively.
V
OCMA
, V
OCMB
(Pins 19, 8): These pins set the output
common mode voltage for the respective channel. They
are internally separate. A 0.1μF external bypass capacitor
is recommended.
Exposed Pad (Pin 21): V
–
. The Exposed Pad must be
connected to same voltage/ground as pins 3, 4, 13, 14.
BLOCK DIAGRAM
642120 BD
7
V
+
B
V
+
B
V
+
A
–OUTA
–OUTB
8
V
OCMB
V
OCMA
+INA
–INA
V
–
V
–
R
OUT
12.5Ω
R
OUT
12.5Ω
R
F
1000Ω
R
G
100Ω
R
F
1000Ω
R
F
1000Ω
R
F
1000Ω
10
V
–
V
–
9
20
V
+
A
+OUTB
+OUTA
19 1718
ENABLEA
ENABLEB
R
OUT
12.5Ω
R
OUT
12.5Ω
R
G
100Ω
R
G
100Ω
R
G
100Ω
1
2
3
4
5
6
16
15
14
13
12
11
–INB
+INB
–
–+
+
+
–
–
+