1. A semiconductor device, comprising:
a memory cell including a flip-flop circuit, for holding data, and a transfer gate; and
a pair of write bit lines for writing data in said memory cell,
wherein in case that data are written in said flip-flop circuit by inverting each voltage to be respectively supplied to said pair of write bit lines, slew rates of said each voltage are configured to be made equal to a predetermined value or less.
2. The semiconductor device according to claim 1, wherein:
said transfer gate is an N channel type transistor; and
in case that data of H level are written in said flip-flop circuit, with respect to the slew rate of the rise waveform of the voltage to be supplied to one of said pair of write bit lines, the slew rate of the fall waveform of the voltage to be supplied to the other of said pair of write bit lines is configured to be made smaller.
3. The semiconductor device according to claim 2, further comprising:
a plurality of buffers disposed one for each of said pair of write bit lines;
wherein driving ability of said buffer, disposed for said other write bit line, for decreasing the voltage of said other write bit line is configured to be lower than driving ability of said buffer, disposed for said one write bit line, for increasing the voltage of said one write bit line.
4. The semiconductor device according to claim 2,
wherein in case that data of L level are written in said flip-flop circuit, with respect to the slew rate of the rise waveform of the voltage to be supplied to said one write bit line of the case that data of H level are written, the slew rate of the fall waveform of the voltage to be supplied to said one write bit line or the slew rate of the rise waveform of the voltage to be supplied to said other write bit line is configured to be made smaller.
5. The semiconductor device according to claim 4, further comprising:
a plurality of buffers disposed one for each of said pair of write bit lines;
wherein driving ability of said buffer, disposed for said one write bit line, for decreasing the voltage of said one write bit line or driving ability of said buffer, disposed for said other write bit line, for increasing the voltage of said other write bit line, is configured to be lower than driving ability of said buffer, disposed for said one write bit line, for increasing the voltage of said one write bit line.
6. The semiconductor device according to claim 1, further comprising:
a plurality of buffers disposed one for each of said pair of write bit lines, and
said one buffer, which is disposed for one of said pair of write bit lines, is configured such that driving ability of the voltage pull up side is higher than specified driving ability, and driving ability of the voltage pull down side is equal to the specified driving ability or less, and
said other buffer, which is disposed for the other of said pair of write bit lines, is configured such that driving ability of the voltage pull up side and the voltage pull down side is equal to the specified driving ability or less.
7. The semiconductor device according to claim 1,
wherein in case that data are written in said flip-flop circuit by inverting the voltages to be respectively supplied to said pair of write bit lines, with respect to the inverting timing of the voltage to be supplied to one of said pair of write bit lines, the inverting timing of the voltage to be supplied to the other of said pair of write bit lines is configured to be shifted.
8. A semiconductor device, comprising:
a memory cell including a flip-flop circuit, for holding data, and a transfer gate; and
a pair of write bit lines for writing data in said memory cell,
wherein in case that data are written in said flip-flop circuit by inverting each voltage to be respectively supplied to said pair of write bit lines, with respect to the inverting timing of the voltage to be supplied to one write bit line in said pair of write bit lines, the inverting timing of the voltage to be supplied to the other write bit line is configured to be shifted.
9. The semiconductor device according to claim 8, wherein:
said transfer gate is an N channel type transistor; and
in case that data of H level are written in said flip-flop circuit, with respect to the inverting timing of the voltage to be supplied to the write bit line of the voltage pull up side in said pair of write bit lines, the inverting timing of the voltage to be supplied to the write bit line of the voltage pull down side is configured to be delayed.
10. The semiconductor device according to claim 1,
wherein as said pair of write bit lines, a plurality of pair of write bit lines are provided.
11. The semiconductor device according to claim 1, further comprising:
read bit lines for reading data from said memory cell; and
a buffer for said read bit lines.
12. The semiconductor device according to claim 1,
wherein said flip-flop circuit is composed of two CMOS inverters being cross coupled.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An apparatus comprising:
a photoconductor having a surface,
an electroconductive material induced on said surface of the photoconductor, which material is connectable to a ground plane in order to conduct electrostatic discharges through the electroconductive material to the ground plane.
2. The apparatus according to claim 1, wherein the photoconductor is provided with an aperture, and that the photoconductor is provided with electroconductive material at least around the edges of the aperture.
3. The apparatus according to claim 1, wherein the electroconductive material is integrated with the photoconductor as a layer of electroconductive material that covers the whole surface of the photoconductor.
4. The apparatus according to claim 3, wherein the electroconductive material is integrated with the photoconductor as a layer of electroconductive material for conducting light in the photoconductor and for shielding the light source against electrostatic pulses.
5. The apparatus according to claim 1, wherein the electroconductive material is metal and is connectable to the ground plane through the electroconductive material.
6. The apparatus according to claim 1, wherein the electroconductive material is realized on the surface of the photoconductor by an electroconductive film, or by inducing chemically or electrochemically.
7. An apparatus for shielding a component against electrostatic discharge comprising a light emitting diode and a photoconductor layer for conducting the light emitted by the light emitting diode, wherein the photoconductor layer includes electroconductive material, and that the electroconductive material is connectable to a ground plane in order to conduct electrostatic discharges from the photoconductor layer to the ground plane.
8. The apparatus according to claim 7, wherein the photoconductor layer is provided with an aperture, so that the light emitting diode is at least partly placed in the aperture, inside the photoconductor layer, and that the photoconductor layer is provided with electroconductive material at least around the edges of the aperture.
9. The apparatus according to claim 7, wherein in the surface of the photoconductor layer there is integrated a layer of electroconductive material, said layer covering the whole surface of the photoconductor layer.
10. The apparatus according to claim 9, wherein in the surface of the photoconductor layer, there is integrated a layer of electroconductive material for shielding the components against electrostatic pulses and for conducting the light emitted by the light emitting diode in the photoconductor layer.
11. The apparatus according to claim 7, wherein the light emitting diode is placed on a printed circuit board, the photoconductor layer is placed on the component side of the circuit board, and the electroconductive material is placed on that side of the photoconductor layer that faces away from the circuit board and the electroconductive material is connectable to the ground plane of the circuit board.
12. The apparatus according to claim 7, wherein the electroconductive material is metal, and it is connected to the ground plane by electroconductive material.
13. The apparatus according to claim 7, wherein the electroconductive material is realized on the surface of the photoconductor layer by an electroconductive film, or by inducing chemically or electrochemically.
14. The apparatus according to claim 7, wherein on the circuit board, there is a light emitting diode for illuminating the keypad, and that the apparatus comprises a photoconductor layer for conducting the light emitted by the light emitting diode to a key.
15. (canceled)
16. The method according to claim 21, wherein the photoconductor layer is provided with an aperture, so that the light emitting diode placed on the circuit board is arranged at least partly in the aperture, inside the photoconductor layer, and that in the photoconductor layer, there is induced electroconductive material at least around the edges of the aperture.
17. The method according to claim 15, claim 21, wherein on the outermost surface of the photoconductor layer, facing away from the circuit board, there is integrated a layer of electroconductive material, which layer covers the whole surface of the photoconductor layer.
18. The method according to claim 17, wherein the electroconductive material is induced for shielding components of the circuit board against electrostatic pulses and for conducting the light emitted by the light emitting diode of the circuit board in the photoconductor layer.
19. The method according to claim 21, wherein the electroconductive material is metallized to the photoconductor layer and connected to the ground plane of the circuit board by electroconductive material.
20. The method according to claim 21, wherein the electroconductive material is realized in the photoconductor layer by an electroconductive film, or by inducing chemically or electrochemically.
21. A method comprising:
placing a light emitting diode on a printed circuit board,
arranging a photoconductor layer on a component side of the circuit board,
inducing an electroconductive material to the photoconductor layer,
connecting the electroconductive material to a ground plane of the circuit board in order to conduct electrostatic discharges from the photoconductor layer to the ground plane of the circuit board.
22. An apparatus comprising:
means for providing a photoconductor having a surface,
means for providing an electroconductive material induced on said surface of the means for providing a photoconductor, which material is connectable to a ground plane in order to conduct electrostatic discharges through the means for providing an electroconductive material to the ground plane.