19-4145; Rev 2; 10/08
Low-Power µP Supervisory Circuits with
Battery-Backup Circuit and Chip-Enable Gating
The MAX16016/MAX16020/MAX16021 supervisory cir-
cuits monitor power supplies, provide battery-backup
control, and chip-enable (CE) gating to write protect
memory in microprocessor (µP)-based systems. These
low-power devices improve system reliability by providing
several supervisory functions in a small, single integrated
The MAX16016/MAX16020/MAX16021 perform four
basic system functions:
1) Provide a µP reset output during VCC supply power-
up, power-down, and brownout conditions.
2) Control VCC to battery-backup switching internally
to maintain data or low-power operation for memo-
ries, real-time clocks (RTCs), and other digital logic
when the main power is removed.
3) Provide memory write protection through internal
chip-enable gating during brownout.
4) Provide a combination of additional supervisory
functions listed in the Features section.
The MAX16016/MAX16020/MAX16021 operate from a
1.53V to 5.5V supply voltage and offer fixed reset
thresholds for monitoring 5V, 3.3V, 3V, 2.5V, and 1.8V
systems. Each device is available with either a push-
pull or open-drain reset output.
The MAX16016/MAX16020/MAX16021 are available in
small TDFN/TQFN packages and are fully specified for
an operating temperature range of -40°C to +85°C.
Main/Backup Power for RTCs, CMOS Memories
o System Monitoring for 5V, 3.3V, 3V, 2.5V, or 1.8V
o 1.53V to 5.5V Operating Voltage Range
o Low 1.2µA Supply Current (0.25µA in Battery-
o 145ms (min) Reset Timeout Period
o Battery Freshness Seal
o On-Board Gating of CE Signals, 1.5ns
Propagation Delay (MAX16020/MAX16021)
o Debounced Manual Reset Input
o Watchdog Timer, 1.2s (typ) Timeout
o Power-Fail Comparator and Low-Line Indicator for
Monitoring Voltages Down to 0.6V
o Battery-On, Battery-OK, and Battery Test
o Small 10-Pin TDFN or 16-Pin TQFN Packages
o UL®-Certified to Conform to IEC60950-1
TEMP RANGE PIN-PACKAGE
-40°C to +85°C
The first placeholder “_” designates all output options. Letter
“L” indicates push-pull outputs and letter “P” indicates open-
drain outputs. The last placeholder “_” designates the reset
threshold (see Table 1).
T = Tape and reel.
+Denotes a lead-free/RoHS-compliant package.
*EP = Exposed pad.
Ordering Information continued at end of data sheet.
Selector Guide located at end of data sheet.
16 15 14 13
BATT 1 +
UL is a registered trademark of Underwriters Laboratories, Inc.
*EP = EXPOSED PAD.
Pin Configurations continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.