Datasheet

MAX2870
23.5MHz to 6000MHz Fractional/
Integer-N Synthesizer/VCO
11Maxim Integrated
Pin Description (continued)
PIN NAME FUNCTION
14 RFOUTB_P Open Collector Positive RF Output B. Connect to supply through RF choke or 50I load.
15 RFOUTB_N Open Collector Negative RF Output B. Connect to supply through RF choke or 50I load.
16 VCC_RF
Power Supply for RF Output and Dividers. Place decoupling capacitors as close as possible
to the pin.
17 VCC_VCO VCO Power Supply. Place decoupling capacitors to the analog ground plane.
18 GND_VCO Ground for VCO. Connect to main board ground plane, not directly to the paddle.
19 NOISE_FILT VCO Noise Decoupling. Place a 1FF capacitor to ground.
20 TUNE Control Input to the VCO. Connect to external loop filter.
21 GND_TUNE
Ground for Control Input to the VCO. Connect to main board ground plane, not directly to the
paddle.
22 RSET
Charge-Pump Current Range Input. Connect an external resistor to ground to set the minimum
CP current. ICP = 1.63/RSET x (1 + CP)
23 BIAS_FILT VCO Noise Decoupling. Place a 1FF capacitor to ground.
24 REG Reference Voltage Compensation. Place a 1FF capacitor to ground.
25 LD
Lock Detect Output. Logic-high when locked, and logic-low when unlocked. See register
description for more details (Table 9).
26 RFOUT_EN RF Output Enable. A logic-low disables the RF outputs.
27 GND_DIG Ground for Digital circuitry. Connect to main board ground plane, not directly to the paddle.
28 VCC_DIG Power Supply for Digital Circuitry. Place decoupling capacitors as close as possible to pin.
29 REF_IN
Reference Frequency Input. This is a high-impedance input with a nominal bias voltage of
VCC_DIG/2. AC-couple to reference signal.
30 MUX_OUT Multiplexed Output and Serial Data Out. See Table 6.
31 GND_SD
Ground for Sigma-Delta Modulator. Connect to main board ground plane, not directly to
the paddle.
32 VCC_SD
Power Supply for Sigma-Delta Modulator. Place decoupling capacitors as close as possible
to the pin.
— EP Exposed Pad. Connect to board ground.