
5.0 Parametric Information
Bt457/Bt458
5.2 AC Electrical Parameters
125 MHz/135 MHz/165 MHz Monolithic CMOS 256 Color Palette RAMDAC
5-6
Conexant
L45801 Rev. N
VAA Supply Current
(3)
IAA
—
—
—
—
—
—
—
Bt458
—
—
310
370
—
235
340
mA
Bt457
—
—
n/a
n/a
—
207
257
mA
NOTE(S):
(1)
Clock and data feedthrough is a function of the number of edge rates and the amount of overshoot and undershoot on the
digital inputs. For this test, the TTL digital inputs have a 1 k
resistor to GND and are driven by 74HC logic. Settling time
does not include clock and data feedthrough. Glitch impulse includes clock and data feedthrough, and
–
3 dB test
bandwidth = 2x clock rate.
(2)
Does not apply to the Bt457.
(3)
At Fmax. IAA (typ) at VAA = 5.0 V and TA = 20
°
C. IAA (max) at VAA = 5.25 V and TA = 0
°
C.
4. Test conditions (unless otherwise specified): "Recommended Operating Conditions" with RSET = 523
and VREF = 1.235 V.
TTL input values are 0
–
3 V with input rise/fall times
≤
4 ns, measured between the 10% and 90% points. ECL input values are
VAA
–
0.8 to VAA
–
1.8 V with input rise/fall times
≤
2 ns, measured between the 20% and 80% points. Timing reference points
at 50% for inputs and outputs. Analog output load
≤
10 pF and D[7:0] output load
≤
75 pF. See timing notes in
Figure 5-1
. As
the above parameters are guaranteed over the full temperature range, temperature coefficients are not specified or required.
Typical values are based on nominal temperature, i.e., room temperature, and nominal voltage, i.e., 5 V.
Table 5-4. AC Characteristics for 165 MHz and 135 MHz Devices
(2 of 2)
165 MHz Devices
135 MHz Devices
Parameter
Symbol
Min
Typ
Max
Min
Typ
Max
Units