SN74HCS11-Q1: Effects of temperature on switching thresholds for HCS logic family

user2

Part Number: SN74HCS11-Q1

For the HCS family, specifically SN74HCS11-Q1, is there any documentation to interpolate the switching thresholds at different operating temperatures?

over 2 years ago

+1 Clemens Ladisch over 2 years ago

Guru 280350 points

The thresholds depend on the characteristics of both complementary input transistors, and the inputs are designed to be symmetric. There is probably not a consistent upward or downward trend for the switchign thresholds.

In any case, the specified minimum/maximum values apply to the entire temperature range, and are the only information that is available.

+1 Emrys Maier over 2 years ago

TI__Guru* 96842 points

Hello,

For the HCS family, you will find that all devices perform very similarly as they were all built on the same technology - ie the design of the inputs and outputs are identical from device to device.

I can share some typical data for the input threshold variation over temperature:

Spec	VCC	-40 C	25 C	85 C	125 C
VT+	2	1.29	1.27	1.25	1.24
VT+	4.5	2.58	2.55	2.53	2.52
VT+	6	3.32	3.28	3.27	3.26
VT-	2	0.74	0.75	0.75	0.76
VT-	4.5	1.69	1.67	1.66	1.66
VT-	6	2.20	2.19	2.18	2.18

Please note that these are typical values for a nominal process device. There is always variation from device to device, and we can only guarantee values provided in the datasheet.

0 user2 over 2 years ago

Prodigy 10 points

Hey Emrys,

Thanks for the table. Do you have any data for when VCC is 3.3V?

+1 Emrys Maier over 2 years ago in reply to user2

TI__Guru* 96842 points

Please see these related FAQs

[FAQ] What are the performance specifications of the HCS logic family at 3.3V operation?

[FAQ] What method is best used for estimating specification values between those given in the datasheet?

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SN74HCS11-Q1: Effects of temperature on switching thresholds for HCS logic family