TC7MBL3253CFK(2009) Просмотр технического описания (PDF) - Toshiba
Номер в каталоге
Компоненты Описание
производитель
TC7MBL3253CFK Datasheet PDF : 12 Pages
| |||
TC7MBL3253CFT/FK/FTG
Rise and Fall Time (tr / tf) of the TC7MBL3253C I/O Signals
The tr(out) and tf(out) values of the output signals are affected by the CR time constant of the input, which consists of
the switch terminal capacitance (CI/O) and the on-resistance (RON) of the input.
In practice, the tr(out) and tf(out) values are also affected by the circuit’s capacitance and resistance components other
than those of the TC7MBL3253C.
The tr(out) / tf(out) values can be approximated as follows. (Figure 3 shows the test circuit.)
tr(out) / tf(out) (approx) = - ( CI/O + CL ) ･ (RDRIVE+ RON) ･ ln ( ( ( VOH – VOL ) – VM) / ( VOH – VOL ) )
Calculation example:
where, RDRIVE is the output impedance of the previous-stage circuit.
tr(out) (approx) = - ( 13 + 15 )E-12 ･ ( 120 + 9) ･ ln ( ( ( 3.0 - 0 ) – 1.5 ) / ( 3.0 – 0 ) )
≈ 2.5 ns
Calculation conditions:
VCC = 3.0V, CL = 15pF , RDRIVE = 120 Ω (output impedance of the previous IC), VM = 1.5V (VCC / 2)
Output of the previous IC = digital (i.e., high-level voltage = VCC; low-level voltage = GND)
Previous IC
RDRIVE
Waveform generated without the TC7MBL3253C
Measure
VCC
GND
Previous IC
RDRIVE
RDRIVE = output impedance of the previous IC
TC7MBL3253C
An/Bn
CI/O
(Switch On)
Bn/An
RON
Waveform generated with the TC7MBL3253C added
Measure
VM
tr(out)
VM
tf(out)
VOH
VOL
RDRIVE = output impedance of the previous IC
項目
VM
3.3 ± 0.3 V
VCC / 2
VCC
2.5 ± 0.2 V
VCC / 2
1.8 ± 0.15 V
VCC / 2
Figure 3 Test Circuit
8
2009-02-02
Share Link: 