ltc6420 Linear Technology Corporation, ltc6420 Datasheet - Page 7

• Manufacturer Part Number: ltc6420
• Description: Dual Matched 1.8ghz Differential Ampli?ers/adc Drivers
• Manufacturer: Linear Technology Corporation

PIN FUNCTIONS
+INA, –INA, –INB, +INB (Pins 1, 2, 5, 6): Differential
Inputs of A and B channel respectively.
V
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.
BLOCK DIAGRAM
–
(Pins 3, 4, 13, 14, 21): Negative Power Supply. All four
+INA
–INA
–INB
+INB
V –
V –
1
2
3
4
5
6
100Ω
100Ω
100Ω
100Ω
R
R
R
R
V
G
G
G
G
V
20
+
7
+
A
B
V
–
+
V
+
+
–
–
OCMA
OCMB
19
8
1000Ω
1000Ω
1000Ω
–
+
R
R
R
+
–
+
–
F
F
F
ENABLEA
ENABLEB
18
V
(Normally tied to 3V or 3.3V). Supply pins of A and B chan-
nels 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
common mode voltage for the respective channel. They
are internally separate. A 0.1μF external bypass capacitor
is recommended.
Exposed Pad (Pin 21): V
nected to same voltage/ground as pins 3, 4, 13, 14.
9
+
OCMA
A , V
12.5Ω
12.5Ω
12.5Ω
12.5Ω
R
R
R
R
OUT
OUT
OUT
OUT
, V
+
B (Pins 15, 20, 7, 12 ): Positive Power Supply
OCMB
+OUTB
+OUTA
10
17
(Pins 19, 8): These pins set the output
640020 BD
16
15
14
13
12
11
–OUTA
V
V –
V –
V
–OUTB
+
+
A
B
–
. The Exposed Pad must be con-
LTC6420-20
642020f
7