Rainbow Electronics MAX16021 User Manual

General Description

The MAX16016/MAX16020/MAX16021 supervisory cir­cuits 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
solution.

The MAX16016/MAX16020/MAX16021 perform four
basic system functions:

1) Provide a µP reset output during V

CC

supply power-

up, power-down, and brownout conditions.

2) Control V

CC

to battery-backup switching internally
to maintain data or low-power operation for memo­ries, 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 push­pull 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.

Applications

Main/Backup Power for RTCs, CMOS Memories

Industrial Control

GPS Systems

Set-Top Boxes

Point-of-Sale Equipment

Portable/Battery Equipment

Features

o System Monitoring for 5V, 3.3V, 3V, 2.5V, or 1.8V

Power-Supply Voltages

o 1.53V to 5.5V Operating Voltage Range
o Low 1.2µA Supply Current (0.25µA in Battery-

Backup Mode)

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

Indicators

o Small 10-Pin TDFN or 16-Pin TQFN Packages
o UL

®

-Certified to Conform to IEC 60950-1

MAX16016/MAX16020/MAX16021

Low-Power µP Supervisory Circuits with

Battery-Backup Circuit and Chip-Enable Gating

________________________________________________________________

Maxim Integrated Products

1

Pin Configurations

19-4145; Rev 3; 12/08

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.

Ordering Information continued at end of data sheet.

Pin Configurations continued at end of data sheet.

Selector Guide located at end of data sheet.

Ordering Information

PART TEMP RANGE

PIN-PACKAGE

MAX16016_TB_+T -40°C to +85°C 10 TDFN-EP*

The first placeholder “_” designates all output options. Letter
“L” indicates push-pull outputs and letter “P” indicates open­drain outputs. The last placeholder “_” designates the reset
threshold (see Table 1).
T = Tape and reel.

+

Denotes a lead(Pb)-free/RoHS-compliant package.

*

EP = Exposed pad.

UL is a registered trademark of Underwriters Laboratories, Inc.

TOP VIEW

VCCCEIN

16

BATT

*EP = EXPOSED PAD.

+

MR

PFI

WDI

5156

LL

CEOUT

OUT

14713

RESET

121

GND

112

MAX16020

*EP

BATTOK

BATT_TEST

TQFN

8

BATTON

PFO

103

WDO

94

MAX16016/MAX16020/MAX16021

Low-Power µP Supervisory Circuits with
Battery-Backup Circuit and Chip-Enable Gating

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= 1.53V to 5.5V, V

BATT

= 3V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

VCC, BATT, OUT, BATT_TEST to GND.....................-0.3V to +6V

RESET, RESET, PFO, BATTOK, WDO, BATTON,

BATT_TEST, LL, (all open-drain) to GND .....................-0.3V to +6V

RESET, RESET, BATTOK, WDO, BATTON,

LL (all push-pull) to GND......................-0.3V to (V

OUT

+ 0.3V)

WDI, PFI to GND.......................................-0.3V to (V

OUT

+ 0.3V)

CEIN, CEOUT to GND ..............................-0.3V to (V

OUT

+ 0.3V)

MR to GND .................................................-0.3V to (V

CC

+ 0.3V)

Input Current

V

CC

Peak Current.................................................................1A

V

CC

Continuous Current ...............................................250mA

BATT Peak Current .......................................................500mA

BATT Continuous Current ...............................................70mA

Output Current

OUT Short Circuit to GND Duration ....................................10s

RESET, RESET, BATTON ....................................................20mA

Continuous Power Dissipation (T

A

= +70°C)

10-Pin TDFN (derate 24.4mW/°C above +70°C) .......1951mW

16-Pin TQFN (derate 25mW/°C above +70°C) ..........2000mW

Thermal Resistance (Note 1)
For 10-Pin TDFN

θ

JA

................................................................................41°C/W

For 16-Pin TQFN

θ

JA

................................................................................40°C/W

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer

board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial

.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Operating Voltage Range
(Note 3)

Supply Current I

Supply Current in
Battery-Backup Mode

VCC Switchover Threshold
Voltage

BATT Switchover Threshold
Voltage

BATT Standby Current VCC > V

BATT Freshness Leakage
Current

VCC to OUT On-Resistance R

Output Voltage in
Battery-Backup Mode

V

CC, VBATTVCC

CC

I

BATT

or V

BATT

VCC > V

TH

VCC = 0V 0.25 0.5 µA

V

rising, VCC - V

CC

falling, VCC < VTH, VCC - V

V

CC

BATT

V

= 5.5V 20 nA

BATT

VCC = 4.75V, I

ON

VCC = 3.15V, I

VCC = 2.35V, I

VCC = 1.91V, I

= 4.5V, I

V

BATT

V

OUT

= 2.5V, I

V

BATT

> V

TH

0 5.5 V

VCC = 1.62V 1.2 2

VCC = 2.8V 1.9 3

VCC = 3.6V 2.3 3.5

VCC = 5.5V 3.4 5

BATT

BATT

0.1

x V

CC

0mV

+ 0.2V -10 +10 nA

= 150mA 1.4 4.5

OUT

= 65mA 1.7 4.5

OUT

= 25mA 2.1 5.0

OUT

= 10mA 2.6 5.5

OUT

V

OUT

OUT

= 20mA

= 20mA

BATT

- 0.1

V

BATT

- 0.15

µA

V

Ω

V

MAX16016/MAX16020/MAX16021

Low-Power µP Supervisory Circuits with

Battery-Backup Circuit and Chip-Enable Gating

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= 1.53V to 5.5V, V

BATT

= 3V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

RESET OUTPUT (RESET, RESET)

Reset Threshold V

VCC Falling to Reset Delay t

Reset Timeout Period t

RESET Output High Voltage
(Push-Pull Output)

RESET Output Leakage Current
(Open-Drain Output)

RESET Output Low Voltage V

RESET Output High Voltage
(Push-Pull Output)

RESET Output Leakage Current
(Open-Drain Output)

POWER-FAIL COMPARATOR

PFI, Input Threshold V

PFI, Hysteresis V

PFI Input Current VCC = 5.5V -1 +1 µA

PFO Output Low Voltage V

TH

VCC falling at 10V/ms 20 µs

RD

RP

VCC ≥ 3.3V, I

VCC ≥ 1.6V, I

OL

VCC ≥ 1.2V, I

V

VCC = 1.1 x VTH, I

OH

RESET deasserted

V

= 5.5V, RESET deasserted 1 µA

RESET

VCC ≥ 3.3V, I

= 3.2mA, RESET asserted 0.3

SINK

= 1mA, RESET asserted 0.3RESET Output Low Voltage V

SINK

= 100µA, RESET asserted 0.3

SINK

= 100µA,

SOURCE

= 3.2mA, RESET

SINK

(see Table 1) V

145 215 285 ms

V

OUT

- 0.3

deasserted

OL

VCC ≥ 1.8V, I

= 1.0mA, RESET

SINK

deasserted

V

OH

PFT

PFT-HYS

OL

VCC = 0.9 x VTH, I
RESET asserted

V

= 5.5V, RESET asserted 1 µA

RESET

VIN falling, 1.6V ≤ VCC ≤ 5.5V 0.572 0.590 0.611 V

VCC ≥ 1.6V, I

VCC ≥ 1.2V, I

= 1mA, output asserted 0.3

SINK

= 100µA, output asserted 0.3

SINK

SOURCE

= 100µA,

V

OUT

- 0.3

30 mV

0.3

0.3

V

V

V

V

V

PFO Output Voltage
High (Push-Pull Output)

V

PFO, Leakage Current
(Open-Drain Output)

PFO, Delay Time V

VCC = 1.1 x VTH, I

OH

asserted

V

SOURCE

= 100µA, output

V

OUT

- 0.3

= 5.5V, output deasserted 1 µA

PFO

+ 100mV to V

PFT

- 100mV 20 µs

PFT

MANUAL RESET (MR)

Input Low Voltage V

Input High Voltage V

IL

IH

0.7 x V

CC

0.3 x V

CC

Pullup Resistance 20 30 kΩ

Glitch Immunity VCC = 3.3V 100 ns
MR to Reset Delay 120 ns

V

V

V

MAX16016/MAX16020/MAX16021

Low-Power µP Supervisory Circuits with
Battery-Backup Circuit and Chip-Enable Gating

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= 1.53V to 5.5V, V

BATT

= 3V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

WATCHDOG TIMER (WDI, WDO)

Watchdog Timeout Period t

Minimum WDI Input Pulse Width t

WDI Input Low Voltage V

WDI Input High Voltage V

WDI Input Current (Note 7) V

WDO Output Low Voltage V

WDO Output High Voltage

(Push-Pull Output)

WDO Leakage Current
(Open-Drain Output)

BATTERY-ON INDICATOR (BATTON)

Output Low Voltage V

BATTON Leakage Current V

BATTON Output High Voltage V

Output Short-Circuit Current
(Note 4)

CE GATING (CEIN, CEOUT)

CEIN Leakage Current Reset asserted, VCC = 0.9 x VTH or 0V -1 +1 µA
CEIN to CEOUT Resistance Reset not asserted (Note 5) 8 50 Ω

CEOUT Short-Circuit Current

CEIN to CEOUT Propagation

Delay

Output High Voltage

Reset to CEOUT Delay 12 µs

0.83 1.235 1.64 s

320 ns

0.7 x
V

CC

V

OUT

- 0.3

V

OUT

- 0.3

0.75 2 mA

0.8 x
V

CC

V

-

BATT

0.1

V

WD

WDI

IL

IH

OL

OH

OL

OH

(Note 6)

(Note 6)

= 0 or 5.5V, time average -1 +1 µA

WDI

VCC = 1.1 x VTH, I
asserted

VCC = 1.1 x VTH, I
deasserted

= 5.5V, WDO deasserted 1 µA

V

WDO

I

= 3.2mA, V

SINK

= 5.5V 1 µA

BATTON

VCC = 0.9 x VTH, I
BATTON asserted

Sink current, V

Reset asserted, CEOUT = 0,
V

= 0.9 x V

CC

50Ω source, C

VCC = 5V, VCC ≥ V

V

= 0V, V

CC

TH

BATT

= 1mA, WDO

SINK

= 100µA, WDO

SOURCE

= 2.1V 0.3 V

BATT

= 100µA,

SOURCE

= 5V 60 mA

CC

= 50pF, VCC = 4.75V 1.5 7 ns

LOAD

BATT

≥ 2.2V I

, I

SOURCE

SOURCE

= 100µA

= 1µA

0.3 x
V

CC

0.3 V

V

V

V

V

V

MAX16016/MAX16020/MAX16021

Low-Power µP Supervisory Circuits with

Battery-Backup Circuit and Chip-Enable Gating

_______________________________________________________________________________________ 5

Note 2: All devices are 100% production tested at TA= +25°C and TA= +85°C. Limits to -40°C are guaranteed by design.
Note 3: V

BATT

can be 0V anytime, or VCCcan go down to 0V if V

BATT

is active (except at startup).

Note 4: Use external current-limit resistor to limit current to 20mA (max).
Note 5: CEIN/CEOUT resistance is tested with V

CC

= 5V and V

CEIN

= 0V or 5V.

Note 6: WDI is internally serviced within the watchdog period if WDI is left unconnected.
Note 7: The WDI input current is specified as the average input current when the WDI input is driven high or low. The WDI input is

designed for a three-stated output device with a 10µA maximum leakage current and capable of driving a maximum capaci­tive load of 200pF. The three-state device must be able to source and sink at least 200µA when active.

ELECTRICAL CHARACTERISTICS (continued)

(VCC= 1.53V to 5.5V, V

BATT

= 3V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)

Table 1a. Reset Threshold Ranges
(MAX16016)

RESET THRESHOLD RANGES (V)

SUFFIX

MIN TYP MAX

L 4.508 4.63 4.906

M 4.264 4.38 4.635

T 2.991 3.08 3.239

S 2.845 2.93 3.080

R 2.549 2.63 2.755

Z 2.243 2.32 2.425

Y 2.117 2.19 2.288

W 1.603 1.67 1.733

V 1.514 1.575 1.639

Table 1b. Reset Threshold Ranges
(MAX16020/MAX16021)

RESET THRESHOLD RANGES (V)

SUFFIX

MIN TYP MAX

L 4.520 4.684 4.852

M 4.275 4.428 4.585

T 3.010 3.100 3.190

S 2.862 2.946 3.034

R 2.568 2.640 2.716

Z 2.260 2.323 2.390

Y 2.133 2.192 2.255

W 1.616 1.661 1.710

V 1.528 1.571 1.618

LOW LINE (LL)

Low Line to Reset Threshold
Voltage

VCC Falling to LL Delay VCC falling at 10V/ms 20 µs

LL Output Low Voltage V

LL Output High Voltage (Push-

Pull Output)

Output Leakage Current VLL = 5.5V, LL deasserted 1 µA

BATTERY-OK INDICATOR (BATTOK, BATT_TEST)

BATTOK Threshold Inferred internally from BATT 2.508 2.6 2.673 V

BATTOK Output Voltage Low V

BATTOK Output High Voltage V

BATTOK Output Leakage
Current

BATT_TEST Output Low Voltage VCC = 1.1 x VTH, I

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

falling (see Table 2) mV

V

CC

OL

V

OH

OL

OH

VCC ≥ 1.6V, I

VCC ≥ 1.2V, I

VCC = 0.9 x V
LL deasserted

VCC = 1.1 x VTH, I
asserted

VCC = 1.1 x VTH, I
BATTOK asserted

V

= 5.5V, deasserted 1 µA

BATTOK

= 1mA, LL asserted 0.3

SINK

= 100µA, LL asserted 0.3

SINK

, I

TH_LL

SOURCE

SINK

SOURCE

SINK

= 100µA,

= 1mA, reset

= 100µA,

= 1mA 0.3 V

V

V

OUT

0.3

OUT

0.3

-

-

0.3 V

V

V

V

MAX16016/MAX16020/MAX16021

Low-Power µP Supervisory Circuits with
Battery-Backup Circuit and Chip-Enable Gating

6 _______________________________________________________________________________________

Typical Operating Characteristics

(V

CC

= 5V, V

BATT

= 0V, TA= +25°C, unless otherwise noted.)

Table 2. Low-Line Threshold Ranges

LOW-LINE THRESHOLD RANGES (V)

SUFFIX

MIN TYP MAX

L 4.627 4.806

4.955

M 4.378 4.543

4.683

T 3.075 3.181 3.274

S

2.922

3.023

3.111

R

2.620

2.409

2.787

Z

2.309

2.383

2.450

Y

2.180

2.246

2.311

W

1.653

1.704

1.752

V

1.563

1.612

1.657

5

MAX16020PTEZ+

4

3

(µA)

CC

I

2

1

VCC SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX16016 toc01

(µA)

CC

I

vs. TEMPERATURE (I

6

MAX16020PTEZ+

5

4

3

2

1

VCC SUPPLY CURRENT

OUT

= 0)

MAX16016 toc02

(µA)

BATT

I

0.7

0.6

0.5

0.4

0.3

0.2

0.1

BATT SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX16020PTEZ+

= 2.5V

V

BATT

MAX16016 toc03

0

1.5 5.5
SUPPLY VOLTAGE (V)

5.04.54.03.53.02.52.0

BATTERY SUPPLY CURRENT

CC

= 0V)

MAX16016 toc04

(µA)

I

BATT

vs. TEMPERATURE (V

0.5

V

= +3.0V

BATT

0.4

0.3

0.2

0.1

0

-15 603510

-40 85

TEMPERATURE (°C)

0

-15 603510

-40 85

TEMPERATURE (°C)

BATT STANDBY CURRENT

vs. TEMPERATURE

5

VCC = 3.2V

4

= 3.0V

V

BATT

3

2

1

0

-1

-2

BATT STANDBY CURRENT (nA)

-3

-4

-5

-40 85

-15 603510

TEMPERATURE (°C)

MAX16016 toc05

0

05.52.01.5 4.03.52.5

4.0

MAX16020PTEZ+

3.5

3.0

2.5

2.0

1.5

TO OUT ON-RESISTANCE (Ω)

1.0

CC

V

0.5

0

1.5 5.55.03.5 4.54.0

SUPPLY VOLTAGE (V)

VCC TO OUT ON-RESISTANCE

vs. SUPPLY VOLTAGE

I

= 25mA

OUT

I

= 10mA

OUT

2.52.0 3.0
SUPPLY VOLTAGE (V)

5.03.00.5 4.51.0

MAX16016 toc06

MAX16016/MAX16020/MAX16021

Low-Power µP Supervisory Circuits with

Battery-Backup Circuit and Chip-Enable Gating

_______________________________________________________________________________________

7

MAXIMUM

TRANSIENT

DURATION

(

)

Typical Operating Characteristics (continued)

(V

CC

= 5V, V

BATT

= 0V, TA= +25°C, unless otherwise noted.)

VCC TO OUT ON-RESISTANCE

5

VCC = +3.15V, I

4

3

2

TO OUT ON-RESISTANCE (Ω)

CC

1

V

0

-15 603510

-40 85

NORMALIZED RESET THRESHOLD

1.005

1.004

1.003

1.002

1.001

1.000

0.999

0.998

0.997

NORMALIZED RESET THRESHOLD

0.996

0.996

-15 603510

-40 85

WATCHDOG TIMEOUT PERIOD

1.5

1.4

1.3

1.2

1.1

1.0

0.9

0.8

0.7

WATCHDOG TIMEOUT PERIOD (s)

0.6

0.5

-15 603510

-40 85

vs. TEMPERATURE

= 65mA

OUT

TEMPERATURE (°C)

vs. TEMPERATURE

TEMPERATURE (°C)

vs. TEMPERATURE

TEMPERATURE (°C)

MAX16016 toc07

BATT TO OUT ON-RESISTANCE (Ω)

µs

MAX16016 toc10

0.65

0.64

MAX16016 toc13

0.63

0.62

0.61

0.60

0.59

PFI THRESHOLD (V)

0.58

0.57

0.56

0.55

BATT TO OUT ON-RESISTANCE

vs. TEMPERATURE (V

5

V

4

BATT

3

2

1

V

BATT

0

-15 603510

-40 85

MAXIMUM TRANSIENT DURATION

vs. RESET THRESHOLD OVERDRIVE

500

450

400

350

300

250

200

150

100

RESET OCCURS ABOVE THE CURVE

50

0

0400350200 300250

RESET THRESHOLD OVERDRIVE (mV)

-15 603510

-40 85

CC

V

= 2.5V

BATT

= 3V

= 4.5V

TEMPERATURE (°C)

10050 150

PFI THRESHOLD

vs. TEMPERATURE

V

PFI+

V

PFI-

TEMPERATURE (°C)

= 0V, I

OUT

MAX16020PTEZ+

= 20mA)

RESET OUTPUT VOLTAGE LOW

0.5

0.4

MAX16016 toc08

0.3

0.2

0.1

RESET OUTPUT VOLTAGE LOW (V)

0

020

210

MAX16020PTEZ+

208

206

MAX16016 toc11

204

202

200

198

196

RESET TIMEOUT PERIOD (ms)

194

192

190

-40 85

NORMALIZED LL THRESHOLD

1.005

1.004

1.003

MAX16016 toc14

1.002

1.001

1.000

0.999

0.998

NORMALIZED LL THRESHOLD

0.997

0.996

0.995

-40 85

vs. SINK CURRENT

MAX16016 toc09

VCC = 3.3V

VCC = 5V

18161412108642

SINK CURRENT (mA)

RESET TIMEOUT PERIOD

vs. TEMPERATURE

MAX16016 toc12

-15 603510

TEMPERATURE (°C)

vs. TEMPERATURE

MAX16016 toc15

-15 603510

TEMPERATURE (°C)