Specifications

Q-1

What are the meanings of + and - in the input/output current of a pin?

A-1

+ means that the current flows in and - means that it flows out.
These signs indicate the direction of the current and do not mean the input/output direction of signals.

	High level	Low level
Input signal	+ (leakage)	- (leakage)
Output signal	-	+

(2007/08)

Q-1

If the input voltage were to exceed the absolute maximum rating even momentarily, would not any problems occur?

A-1

Reliability cannot be guaranteed and the device may be destroyed.
Renesas Electronics designs devices including their withstanding voltage, in order to guarantee input voltage ratings, including long-term reliability, but if the input voltage may exceed the absolute maximum rating, be sure to provide an external protection circuit.

Q-2

Can a power device be used with the total power dissipation (allowable dissipation) exceeded?

A-2

No.
If the total power dissipation is exceeded, the chip temperature (junction temperature) exceeds the absolute maximum rating.

Q-3

The absolute maximum rating of the operating ambient temperature is 80°C, but I want to use the product at 83°C. Are there any problems?

A-3

Yes, there is a problem. The absolute maximum rating must not be exceeded at any time.
Products whose absolute maximum ratings have been exceeded may have suffered the damage even if they seem to be operating normally.

If an absolute maximum rating has been exceeded even slightly, stop using the product and replace it with a new one.

Q-4

The power supply voltage Vdd = -0.3 to 7.0V and the input voltage Vin = -0.3 to Vdd + 0.3 V, so does that mean I can apply a voltage of -0.3 to 7.3 V to the input pins?

A-4

No, the absolute maximum rating of the input voltage is related to Vdd.
If Vdd = 7.0V, 7.3 V on input Pins does not suffer the damage. But, it does not mean the normal operation. In this case, if the electrical specifications (DC characteristics) are, for example, Vdd = 5V±10%, Vin will be -0.3 to 5.8V.

Also, the values that guarantee normal operation must be within the range of the electrical specifications (DC characteristics).

If this range is exceeded, the product will degrade in proportion to how close the values get to the absolute maximum ratings.

Q-5

Does the definition of the storage temperature Tstg apply to when the power supply voltage Vdd is within the range of the electrical specifications (DC characteristics)?

A-5

No, the storage temperature definition applies to when the product is in a non-bias state in which voltage is not being applied to the power supply and input pins.

Q-6

What is the significance of the range between the DC characteristics and absolute maximum rating?

A-6

If the range of the DC characteristics is exceeded, normal operation is not guaranteed.
Some products are damaged as a result. In general, however, exceeding the DC characteristics does not result in instantaneous damage to the product in terms of reliability, as long as it is within the range of the absolute maximum ratings.
However, the closer the excess is to the absolute maximum rating, the more likely the life expectancy of the product will be shortened.

(2007/08)

Q-1

I need to use a product at values that exceed the rated electrical specification range (AC, DC characteristics). Please tell me what values represent the actual power of the product.

A-1

We cannot provide you with this information. If a product exceeds the rated electrical specification range, its operation is not guaranteed.
The characteristics of individual semiconductor devices differ depending on manufacturing deviations, so the shipment test merely confirms that the characteristics of the product fall within the guaranteed range.
Note that exceeding this range even slightly may seriously damage or destroy your product. It is therefore vital that you use your product within the rated electrical specification range.

Q-2

I need to use a product at values that slightly exceed the rated electrical specification range (AC, DC characteristics). Will this have an adverse effect on my product?

A-2

The product is only guaranteed to operate within the rated electrical specification range, so you must judge for yourself whether to exceed this range, even slightly.
If you wish to use the product exceeding this range, you must evaluate and determine whether to use the product on your own responsibility.

There may be cases in which the specifications can be extended, but the feasibility of this depends on the parameters of each product.
For extended specification products, the screening criteria are tightened to enable selection of devices with ideal characteristics from standard products.
These screening specifications are called special specifications, and products with these specifications require a dedicated customized test pattern and a dedicated screening line.
So the cost of the product is correspondingly higher.

If cost is not an issue, it is first necessary to verify whether the product can support special specifications, so please contact one of our sales offices or distributors.

Q-3

Will my product be adversely affected if I exceed the recommended operating conditions?

A-3

The meaning of the recommended operating conditions differs depending on the product. Please refer below.

(1)When operating the product in a range narrower than the AC, DC characteristics:
There is no problem as long as the values are within the AC, DC characteristics range.

(2)When the conditions have not been otherwise prescribed as AC, DC characteristics:
They mean the same as AC, DC characteristics. In this case, operation is not guaranteed if the recommended operating conditions are exceeded.
If the absolute maximum ratings are exceeded, the reliability is also not guaranteed.
With a power device, be sure to confirm that derating is possible with respect to the absolute maximum ratings.
If the above conditions cannot be satisfied, change the IC selection.

(3)When the recommended conditions are related to the operating error:
When the recommended conditions are related to the operating accuracy, such as the communication clock rate, etc., operation is not guaranteed if these conditions are exceeded.

Q-4

Upon power-on of the same digital ICs, some output low level to a given pin while others output high level. Is one of these digital ICs defective?

A-4

The initial status varies depending on the molecular mass of impurities that are doped during the diffusion process as well as the diffusion pattern, which are factors of a level that cannot be controlled in the process. In other words, the initial status, whether high or low, is not indicative of any product defect.

Normally, outputs that require initial status fixing can be initialized through reset execution. Be sure to execute reset when applying power to ICs that have with a reset function.

Q-5

Can a memory module with an input capacitance of Ci = 80pF be directly connected to output pins with a load condition of CL = 100pF ?

A-5

No, you can't. Direct connection under these conditions is difficult.
The load capacitance (CL) is the total of the input capacitance on the load side (Ci), the output capacitance on the driving side (Co), and the wiring capacitance on the board.

In the above case, for example, when Co = 10pF, Co + Ci = 90pF, It means a margin is only 10pF.
So when you add the capacitance of the board wiring pattern, the load becomes excessive.

When evaluating the connection feasibility, it is also necessary to verify the voltage and current driving capability at both high and low level.
If the specifications are not satisfied, you must insert a driver.

In some cases, voltage specifications can be met by inserting a pull-up or pull-down resistor.
But it will be necessary to set a resistance value that satisfies the specifications of the output current and rise/fall time.

Q-6

Regarding digital ICs, the power supply current ratings are provided.
What is the current value during reset input?

A-6

There is no rating in particular for the specific state that is the state during reset, and the only guarantee is that the value is equal to or lower than the maximum value during normal operation.

However, in the case of microcontrollers that incorporate I/O ports, reset makes ports to input.
So that unless the voltage of the ports is fixed externally, a through current flows.
Since this through current flows from the power supply to ground, an excessive current passes in all the input buffers of the corresponding ports, and the current value cannot be determined.

Q-7

The supply current exceeds the specifications.

A-7

The specifications of the supply current do not include the output current of pins. This is because the supply current depends on the load and cannot be defined for its own single device. If an ammeter is connected to the power supply or ground under conditions of connecting loads with output pins, the output current is added.
If the input is open, a through current flows, leading to a possibility that the specifications have been exceeded in a mode such as the power-saving mode.
The conditions which the specified supply current must satisfy are that the output is open and that the input is fixed to the high or low level.

(2006/11)

Q-8

How can the supply current of a digital IC be considered under conditions where the voltage and frequency differ from those defined as the electrical specifications?

A-8

Generally, the supply current is almost proportional to the voltage and frequency within a given operating voltage range. The current consists of two components: leakage current that flows even while the clock is stopped and switching current that depends on the clock frequency. As can be seen from the characteristics of a microcontroller in the STOP mode, the leakage current is negligibly lower than the switching current. The total supply current, therefore, is almost proportional to the frequency. Where the supply current is 10 mA at 5 V and 10 MHz, for example, it can be estimated that the current at 3 V and 5 MHz should be about 3 mA because 10 × (3/5) × (5/10) = 3.

In case of a microcontroller having an on-chip regulator, however, the current barely changes even if the supply voltage changes, because the regulator supplies a constant voltage to the internal circuits (except the clock generator and LCD controller). In this case, take only the frequency into consideration.

(2008/02)

Q-9

What should I do about the output voltage when the digital output current conditions differ from the rated values described in the data sheet?

A-9

For general-purpose ports with phased current value ratings, you can analogize using Ohm's Law (H output falls below VDD, L output rises above GND). Note that for some microcontrollers, the characteristics graphs (reference values) are available on our website .
However, since the output current conditions (maximum value when phased ratings are used) assume the maximum load, don't pass a rated current because this may degrade the reliability of the semiconductor device.

(2007/06)

Q-10

Even when a resonator is connected, the pin voltage of the clock oscillator fails to reach the rated input voltage value and remains an extremely weak voltage. Does this mean the part is broken?

A-10

No. In the case of the clock oscillator pin, the input voltage rating is applied to the voltage level for the clock signal input, which differs from the case of resonator connection. When a probe of a measuring device such as an oscilloscope is applied to this pin during voltage or waveform observation, this affects the oscillation owing to the capacitance, etc., of the probe.

(2007/11)

Q-11

DC and AC characteristics define the minimum and maximum values. Does this mean that the characteristics of a product fluctuate?

A-11

No, it does not. The meaning is different between input and output.
The minimum and maximum values of the output are characteristics peculiar to the product and mean that variations of each product are within the range.
The values of the input refer to an allowable range.
These characteristics of some devices change depending on the temperature, power supply, and input voltage, but the specified range of the minimum and maximum values is not exceeded under the condition of operation within the guaranteed range.

(2008/04)

Q-12

How should the minimum and maximum values of DC and AC characteristics be considered?

A-12

The DC margin and AC margin are determined by the respective values of the output and the corresponding input. In other words, the characteristic range of the output must include that of the input. It can therefore be said that the larger the margin, the better the interface that is less likely to be affected by noise. Consequently, considering connection of a signal line, the preferable direction of the minimum and maximum values is reversed between the input and output.



The DC margin poses a problem in many cases at the high level, and a general countermeasure is to insert a buffer or to pull up by a resistor (the AC margin and current driving capability must be checked).

(2008/04)

Q-1

How is the ambient temperature defined?

A-1

The ambient temperature is defined as follows based on the JEDEC standard, assuming that the semiconductor device and the board are in a state of thermal equilibrium.
When there is no wind and the board is horizontal, the temperature is measured 25 mm below the bottom surface of the board, directly under the center of the semiconductor device.
In forced cooling, the board is either horizontal or vertical. The speed of the wind horizontal to the board is at least 2 m/s. The temperature is measured 25 mm below the bottom surface of the board, 100 to 150 mm upwind from the board (diagonally behind the device).

Reference JEDEC standard: JESD51-2 (no wind), JESD51-6 (wind blowing)

When executing thermal design at the set level, factors such as the temperature distribution, outer casing size, and heat dissipation characteristics must be taken into consideration. Also, since it is difficult to achieve highly accurate thermal design, make sure that your condition settings include sufficient margins.

(2008/07)

Q-1

For most products, there is no mention of the input or output impedance in the electrical characteristics. Does this mean that the impedance is not prescribed?

A-1

In semiconductors, the impedance differs depending on the voltage and other factors. For this reason, the impedance is generally not prescribed in the electrical characteristics. For the actual component, the impedance can be calculated by using Ohms law, under the special conditions indicated in the specifications. For example, consider the case of a CMOS input/output.

If the high-level input leakage current I_LIH = +1 uA (max.) when V_I = 5 V, the input is as follows:
R_I (min.) = 5/(1 x 10^-6) = 5 (MΩ)

The input becomes high impedance like this because the input gate is isolated by an oxide film. For this reason, the state of the MOS input is called high impedance (Hi-Z). Note that generally, the absolute value of the low-level input leakage current I_LIL is the same as I_LIH when V_I = 0 V, so the impedance is the same even when the input level is low.



In the case of the output, if the high-level output voltage V_OH = (V_DD - 0.5 V) (min.) when the current I_OH = 1 mA, the voltage drop from V_DD will be 0.5 V or lower, so the P-channel (V_DD side) on-resistance will be as follows:
R_OH (max.) = 0.5/(1 x 10^-3) = 500 (Ω)



Moreover, if the low-level output voltage V_OL = 0.7 V (max.) when the current I_OL = +5 mA, the N-channel (GND side) on-resistance will be as follows:
R_OL (max.) = 0.7/(5 x 10^-3) = 140 (Ω)

(2009/07)