7

3.0 PIN DESCRIPTION

Flatpack

Pin No.

Name

I/O

Type

Description

37

XTAL1

I

LVTTL

Primary reference clock input.

When interfacing a single-ended reference clock

to the UT7R995 or UT7R995C, this input must be driven by an LVTTL/LVCMOS

clock source.

If a quartz crystal is used as the reference clock source (UT7R995C only), the second

pin on the crystal must be connected to XTAL2. If a singled ended reference clock

is supplied to this pin, then XTAL2 should be left unconnected.

36

N/C

--

--

No Connect.

UT7R995 Only.

XTAL2

O

N/A

Feedback output from the on-board crystal oscillator.

When a crystal is used to

supply the reference clock for the UT7R995C, this pin must be connected to the

second terminal of the quartz crystal. If a single-ended reference clock is supplied

to XTAL1, then this output should be left unconnected.

13

FB

I

LVTTL

Feedback input for the PLL.

When FB is not driven by an active clock output the

PLL will run to its maximum frequency, unless the device is placed in power-down.

28

I

3-Level

Built-in test control signal.

the PLL and the XTAL1 reference frequency is driven to all outputs (except for the

2.0 RADIATION HARDNESS

Table 13: Radiation Hardness Design Specifications

Notes:

4. All SEU data specified in this datasheet is based on the storage elements used in the UT7R995/C.

5. For characterization data on the UT7R995/C SET performance over allowable operating ranges, please contact the factory.

Parameter

Limit

Units

Total Ionizing Dose (TID)

>1E6

rads(Si)

>109

>109

>74

Neutron Fluence

1.0E14