MC10E1652FN 데이터 시트보기 (PDF) - Motorola => Freescale

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MC10E1652FN

Dual ECL Output Comparator With Latch

Motorola => Freescale 

MC10E1652

requirement to effect the correct input-output relationship.

Note that the LEN waveform in Figure 3 shows the LEN

signal swinging around a reference labeled VBBINT; this

waveform emphasizes the requirement that LEN follow

typical ECL 10KH logic levels because VBBINT is the

internally generated reference level, hence is nominally at

the ECL VBB level.

Finally, VOD is the input voltage overdrive and represents

the voltage level beyond the threshold level (VTHR) to which

the input is driven. As an example, if the threshold level is set

on one of the comparator inputs as 80 mV and the input

signal swing on the complementary input is from zero to 100

mV, the positive going overdrive would be 20 mV and the

negative going overdrive would be 80 mV. The result of

differing overdrive levels is that the devices have shorter

propagation delays with greater overdrive because the

threshold level is crossed sooner than the case of lower

overdrive levels. Typically, semiconductor manufactures

refer to the threshold voltage as the input offset voltage

(VOS) since the threshold voltage is the sum of the externally

supplied reference voltage and inherent device offset

voltage.

VBBINT

LEN

V

VIN

VTHR

Q

ts

th

VOD

tPHL

tpw

tPLH(LEN)

Q

Figure 3. Input/Output Timing Diagram

DELAY DISPERSION

Under a constant set of input conditions comparators have

a specified nominal propagation delay. However, since

propagation delay is a function of input slew rate and input

voltage overdrive the delay dispersion parameters, TDE and

TDT, are provided to allow the user to adjust for these

variables (where TDE and TDT apply to inputs with standard

ECL and TTL levels, respectively).

Figure 4 and Figure 5 define a range of input conditions

which incorporate varying input slew rates and input voltage

overdrive. For input parameters that adhere to these

constraints the propagation delay can be described as:

TNOM ± TDE (or TDT)

where TNOM is the nominal propagation delay. TNOM

accounts for nonuniformity introduced by temperature and

voltage variability, whereas the delay dispersion parameter

takes into consideration input slew rate and input voltage

overdrive variability. Thus a modified propagation delay can

be approximated to account for the effects of input conditions

that differ from those under which the parts where tested. For

example, an application may specify an ECL input with a slew

rate of 0.25 V/NS, an overdrive of 17 mV and a temperature

of 25°C, the delay dispersion parameter would be 100 ps.

The modified propagation delay would be

775ps ± 100ps

–0.9 V

– 1.07 V

INPUT

THRESHOLD

RANGE

– 1.58 V

– 1.75 V

SLEW RATE =

0.25 V/NS

SLEW RATE = 0.75 V/NS

Figure 4. ECL Dispersion Test Input Conditions

2.5 V

2.0 V

INPUT

THRESHOLD

RANGE

0.5 V

0V

SLEW RATE =

0.30 V/NS

SLEW RATE = 0.75 V/NS

Figure 5. TTL Dispersion Test Input Conditions

MOTOROLA

2–4

ECLinPS and ECLinPS Lite

DL140 — Rev 4

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