SNVSB04B March 2019 – June 2020 TLV4021 , TLV4031 , TLV4041 , TLV4051

UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.

- 1 Features
- 2 Applications
- 3 Description
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Detailed Description
- 8 Application and Implementation
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information

For the TLV4021 (open-drain output versions of the TLV40x1 family), care should be taken in selecting the pull-up resistor (R_{PU}) value to ensure proper output voltage levels. First, consider the required output high logic level requirement of the logic device that is being driven by the comparator when calculating the maximum R_{PU} value. When in a logic high output state, the output impedance of the comparator is very high but there is a finite amount of leakage current that needs to be accounted for. Use I_{O-LKG} from the EC Table and the V_{IH} minimum from the logic device being driven to determine R_{PU} maximum using Equation 4.

Equation 4.

Next, determine the minimum value for R_{PU} by using the V_{IL} maximum from the logic device being driven. In order for the comparator output to be recognized as a logic low, V_{IL} maximum is used to determine the upper boundary of the comparator's V_{OL}. V_{OL} maximum for the comparator is available in the EC Table for specific sink current levels and can also be found from the V_{OUT} versus I_{SINK} curve in the Typical Application curves. A good design practice is to choose a value for V_{OL} maximum that is 1/2 the value of V_{IL} maximum for the input logic device. The corresponding sink current and V_{OL} maximum value will be needed to calculate the minimum R_{PU}. This method will ensure enough noise margin for the logic low level. With V_{OL} maximum determined and the corresponding I_{SINK} obtained, the minimum R_{PU} value is calculated with Equation 5.

Equation 5.

Since the range of possible R_{PU} values is large, a value between 5 kΩ and 100 kΩ is generally recommended. A smaller R_{PU} value provides faster output transition time and better noise immunity, while a larger R_{PU} value consumes less power when in a logic low output state.