| 摘要 |
The present invention comprises first and second differential pairs (MN 31 , MN 32 ), (MN 33 , MN 34 ) to which first and second differential input signals (CIB 0 , CIT 0 ), (CIB 90 , CIT 90 ) are input, output pairs of said first and second differential pairs being commonly connected to each other, further connected to load circuits (MN 1 to MN 4 ) and connected to differential output terminals (OUTT, OUTB); first to fourth current sources (MN 1 to MN 4 ); and first to fourth switch pairs (MN 11 , MN 21 ), (MN 12 , MN 22 ), (MN 13 , MN 23 ), (MN 14 , MN 24 ). Switches on one side of said first to N-th switch pairs are connected at one end thereof to said first to fourth current sources and are commonly connected at the other end thereof to said second differential pair. Control signals PICT [ 3:0 ], PICB [ 4:0 ] are connected to control terminals of said first to N-th switch pairs, so that a pattern is applied to the control signal. The operation of the current sources can be confirmed by a functional test in which output signals are compared with expected values.
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