Hitec HS-5745MG  Digital Servo - 1/4 and 1/5 scale Upgrade

you do not need anything extra to use digital servos-

Control System: +Pulse Width Control 1500usec Neutral
Required Pulse: 3-5 Volt Peak to Peak Square Wave
Amplifier Type: Digital Amplifier & Mosfet Driver
Operating Voltage: 4.8-6.0 Volts
Operating Temperature Range: -20 to +60 Degree C
Operating Speed (4.8V): 0.18sec/60° at no load
Operating Speed (6.0V): 0.15sec/60° at no load
Stall Torque (4.8V): 208 oz/in. (15kg.cm)
Stall Torque (6.0V): 250 oz/in. (18kg.cm)
Operating Angle: 40 Deg. one side pulse traveling 400usec
360 Modifiable: Yes
Direction: Clockwise/Pulse Traveling 1500 to 1900usec
Current Drain (4.8V): 3mA/idle and 700mA no load operating
Current Drain (6.0V): 3mA/idle and 840mA no load operating
Stall Current (4.8V): 4000mA
Stall Current (6.0V): 4800mA
Dead Band Width: 2usec
Motor Type: Cored Carbon Brush
Potentiometer Drive: 6-Slider, Indirect Drive
Bearing Type: Dual Ball Bearing
Gear Type: 1 Resin, 3 Metal Gears
Connector Wire Length: 11.8" (300mm)
Connector Wire Gauge: 22AWG
Connector Wire Strand Count: 60EA
Dimensions: 2.30" x 1.10"x 2.000" (59 x 29 x 52 mm)
Weight: 5.68oz (161g)