Philips Semiconductors Product data
74AVC16834A
18-bit registered driver with inverted register enable
and Dynamic Controlled Outputs (3-State)
2002 Sep 11
9
TEST CIRCUIT
SWITCH POSITION
PULSE
GENERATOR
R
T
V
I
D.U.T.
V
O
C
L
V
CC
R
L
Test Circuit for switching times
Open
GND
S
1
DEFINITIONS
V
CC
V
I
< 2.3 V V
CC
TEST S
1
t
PLH/
t
PHL
Open
R
L
= Load resistor
C
L
= Load capacitance includes jig and probe capacitance
R
T
= Termination resistance should be equal to Z
OUT
of pulse generators.
2 V
CC
t
PLZ/
t
PZL
V
CC
2.3–2.7 V
t
PHZ/
t
PZH
GND
R
L
2 * V
CC
SV01018
R
L
1000 Ω
500 Ω
V
CC
3.0 V 500 Ω
Waveform 7. Load circuitry for switching times
GRAPHS
SH00204
0
0.5
1
1.5
2
2.5
3
3.5
0 50 100 150 200 250
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
= 3.3 V
V
OL
V
CC
= 2.5 V
V
CC
V
CC
= 1.8 V
I
OL
Figure 1. Output voltage (V
OL
) vs. output current (I
OL
)
SH00205
–250 –200 –150 –100
–50
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
= 3.3 V
= 2.5 V = 1.8 V
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
V
OH
V
CC
I
OH
V
CC
V
CC
Figure 2. Output voltage (V
OH
) vs. output current (I
OH
)
A Dynamic Controlled Output (DCO) circuit is designed in. During
the transition, it initially lowers the output impedance to effectively
drive the load and, subsequently, raises the impedance to reduce
noise. Figures 1 and 2 show V
OL
vs. I
OL
and V
OH
vs. I
OH
curves to
illustrate the output impedance and drive capability of the circuit. At
the beginning of the signal transition, the DCO circuit provides a
maximum dynamic drive that is equivalent to a high drive standard
output device.
