TXC-02050C Transwitch, TXC-02050C Datasheet - Page 19

• Manufacturer Part Number: TXC-02050C
• Description: Line Interface
• Manufacturer: Transwitch

OPERATION
POWER SUPPLY, GROUND AND PLL CONNECTIONS
The MRT device has separate power supply pins labeled VDD and VAGC. The VAGC supply pin is connected
to the internal AGC amplifier and is derived from the VDD supply as indicated in Figure 10. Separate bypass
networks must be used for connecting the VDD and VAGC supply pins on the MRT to +5V. The bypass network
on the VAGC pin consists of a 1N4148 or 1N914 diode, a ferrite bead and a 10 microfarad 6.3 volt (tantalum)
capacitor connected to analog ground in parallel with a 0.1 microfarad capacitor, as shown in Figure 10.
TranSwitch recommends that the 0.1 microfarad decoupling capacitors be of RF quality and that they be con-
nected in close proximity to the device.
The recommended ground plane for the MRT device is a common ground plane for both analog and digital
ground. The ground plane beneath and approximately 0.25" beyond the physical dimensions of the MRT needs
to be separated into analog and digital grounds by notching approximately 25 mils of the copper ground plane,
as shown in Figure 11. Additional MRT application design considerations are discussed in TranSwitch
Application Note AN-517 “Design Considerations for use of the MRT device with the E2/E3F Device.”
capacitor
removed
470
Proprietary TranSwitch Corporation Information for use Solely by its Customers
A
A
A
A
Figure 10. MRT Power Supply, Ground and PLL Connections
23
31
17
22
A
7
VAGC
GNDA
VCOC
PLLC
AGFIL
TXC-02050C
GNDD
GNDD
GNDD
GNDD
GNDD
GNDD
GNDD
GNDD
VDD
VDD
VDD
VDD
VDD
10/6.3v
10
18
35
37
42
11
16
32
36
39
44
1
6
Ferrite Bead *(See Note 2)
DATA SHEET
D
- 19 of 36 -
A
+
D
D
D
D
D
A
10/6.3v
Notes:
1. All capacitors are 0.1 microfarad unless other-
2. Ferrite bead is part number 2743002111 of Fair
wise specified.
Rite Corp., Walkill, NY, [phone] or
equivalent.
D
+
1N914 or 1N4148
D
Legend:
A = Analog Ground
D = Digital Ground
V
DD
, +5V
TXC-02050C
TXC-02050C-MB
Ed. 1, May 2002
MRT