19-1658; Rev 1; 6/01
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup and Chip-Enable Gating
General Description
Features
The MAX6365–MAX6368 supervisory circuits simplify
power-supply monitoring, battery-backup control func-
tions, and memory write protection in microprocessor
(µP) systems. The circuits significantly improve the size,
accuracy, and reliability of modern systems with an ultra-
small integrated solution.
o Low +1.2V Operating Supply Voltage (V or V
o Precision Monitoring of +5.0V, +3.3V, +3.0V, and
+2.5V Power-Supply Voltages
)
CC
BATT
o On-Board Gating of Chip-Enable Signals, 1.5ns
Propagation Delay
o Debounced Manual Reset Input (MAX6365)
o Watchdog Timer, 1.6s Timeout (MAX6366)
o Battery-On Output Indicator (MAX6367)
o Auxiliary User-Adjustable RESET IN (MAX6368)
o Low 10µA Quiescent Supply Current
o Three Available Output Structures
These devices perform four basic system functions:
1) Provide a µP reset output during V
supply power-
CC
up, power-down, and brownout conditions.
2) Internally control V to backup-battery switching to
CC
maintain data or low-power operation for CMOS
RAM, CMOS µPs, real-time clocks, and other digital
logic when the main supply fails.
Push-Pull RESET
Open-Drain RESET
Open-Drain RESET
3) Provide memory write protection through internal
chip-enable gating during supply or processor faults.
o RESET/RESET Valid Down to 1.2V Guaranteed
4) Include one of the following options: a manual reset
input (MAX6365), a watchdog timer function
(MAX6366), a battery-on output (MAX6367), or an
auxiliary user-adjustable reset input (MAX6368).
(V
CC
or V
)
BATT
o Power-Supply Transient Immunity
o 150ms min Reset Timeout Period
o Miniature 8-Pin SOT23 Package
The MAX6365–MAX6368 operate from V
supply volt-
CC
ages as low as 1.2V. The factory preset reset threshold
voltages range from 2.32V to 4.63V (see Ordering
Information). In addition, each part is offered in three
reset output versions: push-pull active low, open-drain
active low, or open-drain active high (see Selector
Guide). The MAX6365–MAX6368 are available in minia-
ture 8-pin SOT23 packages.
Ordering Information
PIN-
PACKAGE
PART*
TEMP. RANGE
MAX6365LKA__-T
MAX6365PKA__-T
MAX6365HKA__-T
MAX6366LKA__-T
MAX6366PKA__-T
MAX6366HKA__-T
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
8 SOT23-8
Applications
Critical µP/µC Power
Monitoring
Portable/Battery-
Powered Equipment
Fax Machines
Set-Top Boxes
POS Equipment
Industrial Control
Computers/Controllers
MAX6367LKA__-T
MAX6367PKA__-T
MAX6367HKA__-T
MAX6368LKA__-T
MAX6368PKA__-T
MAX6368HKA__-T
Pin Configurations
TOP VIEW
RESET, RESET
1
2
3
4
8
7
6
5
CE OUT
BATT
OUT
*These parts offer a choice of reset threshold voltages. From the
Reset Threshold Ranges table, insert the desired threshold volt-
age code in the blank to complete the part number. SOT parts
come in tape-and-reel only and must be ordered in 2500-piece
increments. See Device Marking Codes for a complete parts list,
including SOT top marks and standard threshold versions. See
Selector Guide for a listing of device features.
CE IN
GND
MR
MAX6365
V
CC
SOT23
Pin Configurations continued at end of data sheet.
Typical Operating Circuit appears at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.