Datasheet
MAX2055
Digitally Controlled, Variable-Gain, Differential
ADC Driver/Amplifier
_______________________________________________________________________________________ 9
Pin Description
PIN NAME FUNCTION
1, 9 V
CC
Power Supply. Bypass to GND with capacitors as close to the pin as possible as shown in the typical
application circuits (Figures 1 and 2).
2 RF_IN
Signal Input. Internally matched to 50Ω over the operating frequency. See the typical application
circuit for recommended component values.
3, 18, 20, EP GND
Ground. Use low-inductance layout techniques on the PC board. Solder the exposed paddle to the
board ground plane.
4–8 B4–B0 Attenuation Control Bits. Digital input for attenuation control. See Table 3 for attenuation setting.
10 RF_OUT-
Inverted Differential Signal Output. Requires an external pullup choke inductor (120mA typical
current) to V
CC
along with a DC-blocking capacitor; see Figures 1 and 2.
11 RF_OUT+
Noninverted Differential Signal Output. Requires an external pullup choke inductor (120mA typical
current) to V
CC
along with a DC-blocking capacitor; see Figures 1 and 2.
12 I
BIAS
Amplifier Bias Input. See Figures 1 and 2 for detailed connection.
13 C
BP
Bypass Capacitor. See Figures 1 and 2 for detailed connection.
14 L
E
Amplifier DC Ground. Requires choke inductor that can handle supply current. DC resistance of
inductor should be less than 0.2Ω.
15 AMP
IN
Amplifier Input. Requires DC-coupling to allow biasing.
16 C
C
Compensation Capacitor. Requires connection to AMP
IN
(pin 15) for stability.
17 I
SET
Connect R1 from I
SET
to GND (see Table 1 or Table 2 for values).
19 ATTN
OUT
Attenuator Output. Requires external DC-blocking capacitor.
COMPONENT VALUE SIZE
C1, C3–C6, C8, C9, C10, C12 1nF 0603
C2, C11 100pF 0603
L1, L3 330nH 0603
L2 100nH 0603
L4, L5 680nH 1008
R1 1.13kΩ 0603
R7 10Ω 0603
T1, T2 1:1 —
Table 1. Suggested Components of
Circuit of Figure 1
COMPONENT VALUE SIZE
C1, C3, C4, C5, C7–C10, C12 1nF 0603
C2, C11 100pF 0603
L1, L2, L3 330nH 0603
L4, L5 680nH 1008
R1 909Ω 0603
R7 10Ω 0603
T2 1:1 —
Table 2. Suggested Components of
Circuit of Figure 2