Features
- Single Voltage Monitoring Supervisors
- Fixed-Voltage Options Allow Precise Monitoring of +1.8V, +2.5V, +3.0V, +3.3V and +5.0V Power Supplies
- Ultra Low 160nA Supply Current
- ±1.2% Voltage Threshold Accuracy
- 190ms Power-On Reset Timeout
- Reset Signal Valid Down to VDD = 1V
- No External Components Necessary
- Immune to Power-Supply Transients
- Available in Small 3 Ld SC-70 and 3 Ld SOT-23 Pb-free Packages
- Pin Compatible with MAX803, MAX809, MAX810
- Pb-Free (RoHS Compliant)
ISL8800x Functional Diagram
Description
The ISL88001, ISL88002, ISL88003 supervisors are extremely low power 160nA voltage supervisors that help to monitor the power supply voltages in a wide variety of applications. By providing Power-On Reset and supply voltage supervision in small 3 Ld SC-70 and SOT-23 packages, the ISL88001, ISL88002, ISL88003 devices can help to lower system cost, reduce board space requirements and increase the reliability of systems. The most popular voltage trip points are available for standard power supplies from 1. 8V to 5. 0V (see “Ordering Information” on page 3). These reset threshold voltages are accurate to within ±1. 2% and the reset signal is valid down to 1V. Active high and active low reset outputs are available in push-pull and open drain configurations (see “Functional Block Diagrams” on page 2). The ISL88001, ISL88002, ISL88003 devices are specifically designed for low power consumption and high threshold accuracy, making them especially suitable for electronic devices and portable equipment.
Applications
- Microprocessor/Microcontroller Systems
- Intelligent Instruments
- Controllers
- Computer Systems
- Portable/Battery-Powered Equipment
- PDA and Hand-Held PC Devices
| Part Number | Status | Samples | Stock | RoHS | Package | Lead Count (#) | Carrier Type | Moisture Sensitivity Level (MSL) | Pitch (mm) | Pkg. Dimensions (mm) | Pb (Lead) Free | Pb Free Category | Temp. Range (°C) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ISL88003IE16Z-T | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 0.7mm | 0.0 x 0.0 x 1.90 | No | -40 to +85°C | ||
| ISL88003IE16Z-T7A | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 0.7mm | 0.0 x 0.0 x 1.90 | No | -40 to +85°C | ||
| ISL88003IE16Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 0.7mm | 0.0 x 0.0 x 1.90 | No | -40 to +85°C | ||
| ISL88003IE17Z-T | Obsolete | N/A | In Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE17Z-T7A | Obsolete | N/A | In Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE17Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE22Z-T | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 0.7mm | 0.0 x 0.0 x 1.90 | No | -40 to +85°C | ||
| ISL88003IE22Z-T7A | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 0.7mm | 0.0 x 0.0 x 1.90 | No | -40 to +85°C | ||
| ISL88003IE22Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 0.7mm | 0.0 x 0.0 x 1.90 | No | -40 to +85°C | ||
| ISL88003IE23Z-T | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE23Z-T7A | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE23Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE26Z-T | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE26Z-T7A | Obsolete | N/A | In Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE26Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE29Z-T | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 0.7mm | 0.0 x 0.0 x 1.90 | No | -40 to +85°C | ||
| ISL88003IE29Z-T7A | Obsolete | N/A | In Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE29Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 0.7mm | 0.0 x 0.0 x 1.90 | No | -40 to +85°C | ||
| ISL88003IE31Z-T | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE31Z-T7A | Obsolete | N/A | In Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE31Z-TK | Obsolete | N/A | In Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE44Z-T | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 0.7mm | 0.0 x 0.0 x 1.90 | No | -40 to +85°C | ||
| ISL88003IE44Z-T7A | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 0.7mm | 0.0 x 0.0 x 1.90 | No | -40 to +85°C | ||
| ISL88003IE44Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SC70 | 3# | Reel | 0.7mm | 0.0 x 0.0 x 1.90 | No | -40 to +85°C | ||
| ISL88003IE46Z-T | Obsolete | N/A | In Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE46Z-T7A | Obsolete | N/A | In Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IE46Z-TK | Obsolete | N/A | In Stock | RoHS:EN | SC70 | 3# | Reel | 3 | 0.7mm | 0.0 x 0.0 x 1.90 | Yes | Nickel/Palladium/Gold-e4 | -40 to +85°C |
| ISL88003IH16Z-T | Obsolete | N/A | In Stock | RoHS:EN | SOT23 | 3# | Reel | 3 | 2.9 x 1.3 x 0.00 | Yes | Pb-Free 100% Matte Tin Plate w/Anneal-e3 | -40 to +85°C | |
| ISL88003IH16Z-T7A | Obsolete | N/A | In Stock | RoHS:EN | SOT23 | 3# | Reel | 3 | 2.9 x 1.3 x 0.00 | Yes | Pb-Free 100% Matte Tin Plate w/Anneal-e3 | -40 to +85°C | |
| ISL88003IH16Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 3 | 2.9 x 1.3 x 0.00 | Yes | Pb-Free 100% Matte Tin Plate w/Anneal-e3 | -40 to +85°C | |
| ISL88003IH17Z-T | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH17Z-T7A | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH17Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH22Z-T | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH22Z-T7A | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH22Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH23Z-T | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH23Z-T7A | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 3 | 2.9 x 1.3 x 0.00 | Yes | Pb-Free 100% Matte Tin Plate w/Anneal-e3 | -40 to +85°C | |
| ISL88003IH23Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH26Z-T | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH26Z-T7A | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 3 | 2.9 x 1.3 x 0.00 | Yes | Pb-Free 100% Matte Tin Plate w/Anneal-e3 | -40 to +85°C | |
| ISL88003IH26Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH29Z-T | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH29Z-T7A | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH29Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH31Z-T | Obsolete | N/A | In Stock | RoHS:EN | SOT23 | 3# | Reel | 3 | 2.9 x 1.3 x 0.00 | Yes | Pb-Free 100% Matte Tin Plate w/Anneal-e3 | -40 to +85°C | |
| ISL88003IH31Z-T7A | Obsolete | N/A | In Stock | RoHS:EN | SOT23 | 3# | Reel | 3 | 2.9 x 1.3 x 0.00 | Yes | Pb-Free 100% Matte Tin Plate w/Anneal-e3 | -40 to +85°C | |
| ISL88003IH31Z-TK | Obsolete | N/A | In Stock | RoHS:EN | SOT23 | 3# | Reel | 3 | 2.9 x 1.3 x 0.00 | Yes | Pb-Free 100% Matte Tin Plate w/Anneal-e3 | -40 to +85°C | |
| ISL88003IH44Z-T | Obsolete | N/A | In Stock | RoHS:EN | SOT23 | 3# | Reel | 3 | 2.9 x 1.3 x 0.00 | Yes | Pb-Free 100% Matte Tin Plate w/Anneal-e3 | -40 to +85°C | |
| ISL88003IH44Z-T7A | Obsolete | N/A | In Stock | RoHS:EN | SOT23 | 3# | Reel | 3 | 2.9 x 1.3 x 0.00 | Yes | Pb-Free 100% Matte Tin Plate w/Anneal-e3 | -40 to +85°C | |
| ISL88003IH44Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C | |||
| ISL88003IH46Z-T | Obsolete | N/A | In Stock | RoHS:EN | SOT23 | 3# | Reel | 3 | 2.9 x 1.3 x 0.00 | Yes | Pb-Free 100% Matte Tin Plate w/Anneal-e3 | -40 to +85°C | |
| ISL88003IH46Z-T7A | Obsolete | N/A | In Stock | RoHS:EN | SOT23 | 3# | Reel | 3 | 2.9 x 1.3 x 0.00 | Yes | Pb-Free 100% Matte Tin Plate w/Anneal-e3 | -40 to +85°C | |
| ISL88003IH46Z-TK | Obsolete | N/A | Out of Stock | RoHS:EN | SOT23 | 3# | Reel | 2.9 x 1.3 x 0.00 | No | -40 to +85°C |
Loading
Filters
Applied Filters
Log in required to subscribe
- Product Change NoticePDF 133 KB Feb 10, 2021
- Product Change NoticePDF 201 KB PCN11088 Sep 07, 2011
- Product Change NoticePDF 181 KB PCN11006 Apr 04, 2011
- Application NotePDF 397 KB an1684 Jan 19, 2004AI-generated Summary: The document outlines important legal disclaimers and usage guidelines for semiconductor products. It emphasizes user responsibility for product design and safety, disclaims liability for damages, and clarifies no intellectual property licenses are granted. Products are categorized by quality grades with specific application recommendations. Users must comply with laws, avoid unauthorized modifications, and ensure safe use within specified conditions. Contact details for Renesas Electronics sales offices worldwide are provided.
- Application NotePDF 509 KB an1681 Jan 19, 2004AI-generated Summary: The document explains grounding techniques for PCB layouts using a dual op amp example on a single-layer copper board. It compares three grounding schemes: a center spine ground trace, an outer ground plane, and a split/star ground plane, highlighting the benefits of single-point grounding to minimize noise and antenna effects. It emphasizes following current paths, minimizing loop lengths, and ensuring close forward and return paths to reduce interference. The document also includes disclaimers on product use, quality grades, safety, and legal compliance.
- Application NotePDF 227 KB an1403 Jan 19, 2004AI-generated Summary: This document provides important legal and usage notices regarding semiconductor products. It emphasizes user responsibility for product design and compliance with laws, disclaims liability for damages, and restricts unauthorized modifications or reverse engineering. Products are categorized by quality grades for specific applications, excluding high-risk uses unless explicitly designated. Users must follow specified operating conditions and implement safety measures. Contact information for Renesas Electronics sales offices worldwide is provided.
Recommended Documents (1)
Datasheets (1)
No Results Found.
Check Spelling
Make sure all keywords are spelled correctly.
Make sure all keywords are spelled correctly.
Adjust Keywords
Try fewer, different, or more general terms to vary your search.
Try fewer, different, or more general terms to vary your search.
Review Filters
If you have filters applied, consider deselecting some to broaden your results.
If you have filters applied, consider deselecting some to broaden your results.
Need help?
- Search our extensive knowledgebase, designed to help customers with their FAQs.
- Get help from our expert Renesas technical staff and community on our support forums.
- Application NotePDF 397 KB an1684 Jan 19, 2004AI-generated Summary: The document outlines important legal disclaimers and usage guidelines for semiconductor products. It emphasizes user responsibility for product design and safety, disclaims liability for damages, and clarifies no intellectual property licenses are granted. Products are categorized by quality grades with specific application recommendations. Users must comply with laws, avoid unauthorized modifications, and ensure safe use within specified conditions. Contact details for Renesas Electronics sales offices worldwide are provided.
- Application NotePDF 509 KB an1681 Jan 19, 2004AI-generated Summary: The document explains grounding techniques for PCB layouts using a dual op amp example on a single-layer copper board. It compares three grounding schemes: a center spine ground trace, an outer ground plane, and a split/star ground plane, highlighting the benefits of single-point grounding to minimize noise and antenna effects. It emphasizes following current paths, minimizing loop lengths, and ensuring close forward and return paths to reduce interference. The document also includes disclaimers on product use, quality grades, safety, and legal compliance.
- Application NotePDF 227 KB an1403 Jan 19, 2004AI-generated Summary: This document provides important legal and usage notices regarding semiconductor products. It emphasizes user responsibility for product design and compliance with laws, disclaims liability for damages, and restricts unauthorized modifications or reverse engineering. Products are categorized by quality grades for specific applications, excluding high-risk uses unless explicitly designated. Users must follow specified operating conditions and implement safety measures. Contact information for Renesas Electronics sales offices worldwide is provided.
Application Notes & White Papers (3)
- Product Change NoticePDF 133 KB Feb 10, 2021
- Product Change NoticePDF 201 KB PCN11088 Sep 07, 2011
- Product Change NoticePDF 181 KB PCN11006 Apr 04, 2011
Product Notices (PCN, EOL, etc) (5)
No Results Found.
Check Spelling
Make sure all keywords are spelled correctly.
Make sure all keywords are spelled correctly.
Adjust Keywords
Try fewer, different, or more general terms to vary your search.
Try fewer, different, or more general terms to vary your search.
Review Filters
If you have filters applied, consider deselecting some to broaden your results.
If you have filters applied, consider deselecting some to broaden your results.
Need help?
- Search our extensive knowledgebase, designed to help customers with their FAQs.
- Get help from our expert Renesas technical staff and community on our support forums.
No Results Found.
Check Spelling
Make sure all keywords are spelled correctly.
Make sure all keywords are spelled correctly.
Adjust Keywords
Try fewer, different, or more general terms to vary your search.
Try fewer, different, or more general terms to vary your search.
Review Filters
If you have filters applied, consider deselecting some to broaden your results.
If you have filters applied, consider deselecting some to broaden your results.
Need help?
- Search our extensive knowledgebase, designed to help customers with their FAQs.
- Get help from our expert Renesas technical staff and community on our support forums.
No Results Found.
Check Spelling
Make sure all keywords are spelled correctly.
Make sure all keywords are spelled correctly.
Adjust Keywords
Try fewer, different, or more general terms to vary your search.
Try fewer, different, or more general terms to vary your search.
Review Filters
If you have filters applied, consider deselecting some to broaden your results.
If you have filters applied, consider deselecting some to broaden your results.
Need help?
- Search our extensive knowledgebase, designed to help customers with their FAQs.
- Get help from our expert Renesas technical staff and community on our support forums.
No Results Found.
Check Spelling
Make sure all keywords are spelled correctly.
Make sure all keywords are spelled correctly.
Adjust Keywords
Try fewer, different, or more general terms to vary your search.
Try fewer, different, or more general terms to vary your search.
Review Filters
If you have filters applied, consider deselecting some to broaden your results.
If you have filters applied, consider deselecting some to broaden your results.
Need help?
- Search our extensive knowledgebase, designed to help customers with their FAQs.
- Get help from our expert Renesas technical staff and community on our support forums.
No Results Found.
Check Spelling
Make sure all keywords are spelled correctly.
Make sure all keywords are spelled correctly.
Adjust Keywords
Try fewer, different, or more general terms to vary your search.
Try fewer, different, or more general terms to vary your search.
Review Filters
If you have filters applied, consider deselecting some to broaden your results.
If you have filters applied, consider deselecting some to broaden your results.
Need help?
- Search our extensive knowledgebase, designed to help customers with their FAQs.
- Get help from our expert Renesas technical staff and community on our support forums.
No Results Found.
Check Spelling
Make sure all keywords are spelled correctly.
Make sure all keywords are spelled correctly.
Adjust Keywords
Try fewer, different, or more general terms to vary your search.
Try fewer, different, or more general terms to vary your search.
Review Filters
If you have filters applied, consider deselecting some to broaden your results.
If you have filters applied, consider deselecting some to broaden your results.
Need help?
- Search our extensive knowledgebase, designed to help customers with their FAQs.
- Get help from our expert Renesas technical staff and community on our support forums.
No Results Found.
Check Spelling
Make sure all keywords are spelled correctly.
Make sure all keywords are spelled correctly.
Adjust Keywords
Try fewer, different, or more general terms to vary your search.
Try fewer, different, or more general terms to vary your search.
Review Filters
If you have filters applied, consider deselecting some to broaden your results.
If you have filters applied, consider deselecting some to broaden your results.
Need help?
- Search our extensive knowledgebase, designed to help customers with their FAQs.
- Get help from our expert Renesas technical staff and community on our support forums.
No Results Found.
Check Spelling
Make sure all keywords are spelled correctly.
Make sure all keywords are spelled correctly.
Adjust Keywords
Try fewer, different, or more general terms to vary your search.
Try fewer, different, or more general terms to vary your search.
Review Filters
If you have filters applied, consider deselecting some to broaden your results.
If you have filters applied, consider deselecting some to broaden your results.
Need help?
- Search our extensive knowledgebase, designed to help customers with their FAQs.
- Get help from our expert Renesas technical staff and community on our support forums.
No Results Found.
Check Spelling
Make sure all keywords are spelled correctly.
Make sure all keywords are spelled correctly.
Adjust Keywords
Try fewer, different, or more general terms to vary your search.
Try fewer, different, or more general terms to vary your search.
Review Filters
If you have filters applied, consider deselecting some to broaden your results.
If you have filters applied, consider deselecting some to broaden your results.
Need help?
- Search our extensive knowledgebase, designed to help customers with their FAQs.
- Get help from our expert Renesas technical staff and community on our support forums.
No Results Found.
Check Spelling
Make sure all keywords are spelled correctly.
Make sure all keywords are spelled correctly.
Adjust Keywords
Try fewer, different, or more general terms to vary your search.
Try fewer, different, or more general terms to vary your search.
Review Filters
If you have filters applied, consider deselecting some to broaden your results.
If you have filters applied, consider deselecting some to broaden your results.
Need help?
- Search our extensive knowledgebase, designed to help customers with their FAQs.
- Get help from our expert Renesas technical staff and community on our support forums.
Support Communities
-
[RH850/F1KM]External voltage monitoring
Hello team In order to implement external voltage monitoring mentioned in the Safety Application Note, is there any recommended chip from Renesas? BR. Xianti
Mar 4, 2025
Support Communities
Get quick technical support online from Renesas Engineering Community technical staff.
Knowledge Base
Browse our knowledge base for helpful articles, FAQs, and other useful resources.
