Maxim MAX1681ESA, MAX1681C-D, MAX1680C-D, MAX1680ESA Datasheet

_______________General Description

The MAX1680/MAX1681 inductorless switched-capaci­tor voltage converters either invert an input voltage of
+2.0V to +5.5V or double it while supplying up to
125mA output current. They have a selectable-frequen­cy option that allows the use of small capacitors: 4.7µF
(MAX1680), 1µF (MAX1681). With their high output cur­rent capability, these charge-pump devices are suit­able replacements for inductor-based regulators, which
require more expensive external components and addi­tional board space.

The devices’ equivalent output resistance (typically

3.5Ω) allows them to deliver as much as 125mA with
only a 440mV drop. A shutdown feature reduces quies­cent current to less than 1µA. The MAX1680/MAX1681
are available in 8-pin SO packages. For devices that
deliver up to 50mA in smaller µMAX packages, refer to
the MAX860/MAX861 data sheet.

________________________Applications

Local Negative Supplies
Interface Power Supplies
Op-Amp Power Supplies
MOSFET Bias

____________________________Features

♦ Selectable Switching Frequencies:

125kHz/250kHz (MAX1680)
500kHz/1MHz (MAX1681)

♦ Allow Use of Small Capacitors

(1µF for the MAX1681)

♦ 125mA Output Current
♦ 3.5Ω Output Impedance
♦ 1µA Logic-Controlled Shutdown
♦ Configurable as Voltage Inverters or Doublers
♦ +2.0V to +5.5V Input Voltage Range
♦ Available in 8-Pin SO Packages
♦ 90% Efficiency

MAX1680/MAX1681

125mA, Frequency-Selectable,

Switched-Capacitor Voltage Converters

________________________________________________________________

Maxim Integrated Products

1

MAX1681

FSEL IN

CAP+ SHDN

GND

C1

1µF

+V

INPUT

+3V TO +5.5V

INVERTED
OUTPUT
VOLTAGE

C2

1µF

1µF

LV

CAP-

INVERTER CONFIGURATION

OUT

MAX1681

FSEL IN

CAP+ SHDN

GND

C1

1µF

C2

1µF

DOUBLED
OUTPUT
VOLTAGE

+V

INPUT

+4V TO +5.5V

NOTE: USE 4.7µF CAPACITORS FOR MAX1680
INPUT VOLTAGE RANGE: +2.5V TO +5.5V.

NOTE: USE 4.7µF CAPACITORS FOR MAX1680
INPUT VOLTAGE RANGE: +2.0V TO +5.5V.

1µF

LV

CAP-

DOUBLER CONFIGURATION

OUT

__________________________________________________Typical Operating Circuits

19-1247; Rev 0; 7/97

PART

MAX1680C/D

MAX1680ESA
MAX1681C/D

0°C to +70°C

-40°C to +85°C

0°C to +70°C

TEMP. RANGE PIN-PACKAGE

Dice*
8 SO
Dice*

______________Ordering Information

*

Contact factory for dice specifications.

Pin Configuration appears at end of data sheet.

MAX1681ESA -40°C to +85°C 8 SO

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone] ext. 3468.

V

MAX1680/MAX1681

125mA, Frequency-Selectable,
Switched-Capacitor Voltage Converters

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(

Typical Operating Circuits

(inverter configuration), FSEL = LV = GND, VIN= 5V, C1 = C2 = 10µF (MAX1680), C1 = C2 = 2.2µF

(MAX1681), T

A

= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)

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.

IN..............................................................................-0.3V to +6V

LV....................................................(V

OUT

- 0.3V) to (VIN+ 0.3V)

CAP+ ...........................................................-0.3V to (V

IN

+ 0.3V)

SHDN, FSEL ......................................(V

LV

- 0.3V) to (VIN+ 0.3V)

OUT, CAP-..................................................................-6V to 0.3V

Continuous Output Current ..............................................135mA

Output Short-Circuit Duration to GND (Note 1) ...................1sec

Continuous Power Dissipation (T

A

= +70°C)

SO (derate 5.88mW/°C above +70°C)..........................471mW

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

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

Storage Temperature Range.............................-65°C to +160°C

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

I

LOAD

= 125mA

Inverter configuration,
RL= 1kΩ, LV = GND

LV = GND (Note 3)

FSEL = IN or LV
SHDN = IN
OUT = GND, SHDN = IN

CONDITIONS

375 500 625

750 1000 1250

94 125 156

187 250 313

4V

IH

V-3.75 -4.56V

LOAD

Output Voltage Under Load
(Note 2)

V

3.0 5.5

2.0 5.5

V

1V

IL

Shutdown, FSEL Thresholds

µA-1 1I

FSEL

Input Bias Current (FSEL)

Ω3.5 10R

OUT

Output Resistance (Note 2)

Ω1 5R

OUT(SHUT)

Output Resistance to Ground
in Shutdown

µA1I+

SHDN

Shutdown Current

µA-1 1I

SHDN

Input Bias Current (SHDN)

UNITSMIN TYP MAXSYMBOLPARAMETER

Doubler configuration,
RL= 1kΩ, LV = OUT

4.0 5.5

V

IN

2.5 5.5

Input Voltage Range

MAX1680

5.4

mA

10.8

FSEL = IN
(125kHz)

FSEL = LV
(250kHz)

MAX1681

21.6

43.2

I+

FSEL = IN
(500kHz)

Supply Current

FSEL = LV
(1MHz)

Note 1: Shorting OUT to IN may damage the device and should be avoided.

TA= +25°C

TA= +25°C

TA= +25°C

TA= +25°C

MAX1681

MAX1680

MAX1681

MAX1680

TA= +25°C

TA= +25°C

TA= +25°C

TA= +25°C

2.5 4.5

5 9

10 18

20 36

FSEL = LV

157 348

FSEL = IN

MAX1680

79 174

FSEL = LV

570 1490

kHz

FSEL = IN

MAX1681

f

OSC

Switching Frequency

285 745

mA

ELECTRICAL CHARACTERISTICS

(

Typical Operating Circuits

(inverter configuration), FSEL = LV = GND, VIN= 5V, C1 = C2 = 10µF (MAX1680), C1 = C2 = 2.2µF

(MAX1681), T

A

= -40°C to +85°C, unless otherwise noted.) (Note 4)

MAX1680/MAX1681

125mA, Frequency-Selectable,

Switched-Capacitor Voltage Converters

_______________________________________________________________________________________ 3

FSEL = IN

FSEL = LV

MAX1681

I

LOAD

= 125mA

21.6

mA

Inverter configuration,
RL= 1kΩ, LV = GND

43.2

Doubler configuration,
R

L

= 1kΩ, LV = OUT

MAX1681

FSEL = LV
FSEL = IN

MAX1680

LV = GND (Note 3)

FSEL = IN or LV
SHDN = IN
OUT = GND, SHDN = IN

CONDITIONS

I+

FSEL = IN
(500kHz)

Supply Current

FSEL = LV
(1MHz)

kHz

285 745

f

OSC

570 1490

79 174

157 348

Switching Frequency

4V

IH

V-3.75V

LOAD

Output Voltage Under Load
(Note 2)

3.0 5.5
V

2.0 5.5

4.0 5.5

V

IN

V

-1 1V

IL

Shutdown, FSEL Thresholds

µA-1 1I

FSEL

Input Bias Current (FSEL)

Ω10R

OUT

Output Resistance (Note 2)

Ω5R

OUT(SHUT)

Output Resistance in
Shutdown

µA1I+

SHDN

Shutdown Current

µA1I

SHDN

Input Bias Current (SHDN)

UNITSMIN TYP MAXSYMBOLPARAMETER

MAX1681

MAX1680

2.5 5.5

Input Voltage Range

MAX1681

MAX1680

MAX1680

5.4

10.8

FSEL = IN
(125kHz)

FSEL = LV
(250kHz)

ELECTRICAL CHARACTERISTICS (continued)

(

Typical Operating Circuits

(inverter configuration), FSEL = LV = GND, VIN= 5V, C1 = C2 = 10µF (MAX1680), C1 = C2 = 2.2µF

(MAX1681), T

A

= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)

Note 2: C1 and C2 are low-ESR (<0.2Ω) capacitors. Capacitor ESR adds to the circuit’s output resistance. Using capacitors with

higher ESR reduces output voltage and efficiency. The specified output resistance includes the C1 and C2 0.2Ω ESR.

Note 3: The typical threshold for V

INPUT

other than +5V is 0.35V

INPUT(VIL

= VIH).

Note 4: Specifications to -40°C are guaranteed by design, not production tested.

RL= 100Ω to GND, FSEL = IN

MAX1680
MAX1681

%

80

90

Power Efficiency

UNITSMIN TYP MAXSYMBOLPARAMETER CONDITIONS

MAX1680/MAX1681

125mA, Frequency-Selectable,
Switched-Capacitor Voltage Converters

4 _______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

(All curves generated using the inverter configuration shown in the

Typical Operating Circuit

s with LV = GND, FSEL = IN or LV,
C1 = C2 = 10µF (MAX1680), C1 = C2 = 2.2µF (MAX1681), and TA= +25°C, unless otherwise noted. Test results are also valid for
the doubler configuration with LV = OUT and TA= +25°C.)

2.5

3.5

5.5

4.5

7.5

6.5

8.5

2.52.0 3.0 3.5 4.0 4.5 5.0 5.5

OUTPUT SOURCE RESISTANCE

vs. SUPPLY VOLTAGE

MAX1680/81TOC04

SUPPLY VOLTAGE (V)

OUTPUT SOURCE RESISTANCE (Ω)

0

1

3

2

5

4

6

-20-40 0 20 40 60 80 100

OUTPUT SOURCE RESISTANCE vs.

TEMPERATURE

MAX1680/81TOC05

TEMPERATURE (°C)

OUTPUT SOURCE RESISTANCE (Ω)

V

INPUT

= 3V

V

INPUT

= 5V

100

0

1 100 1000

MAX1680 EFFICIENCY vs.

LOAD CURRENT (INVERTER CONFIGURATION)

20

40

60

80

MAX1680/81TOC06

LOAD CURRENT (mA)

EFFICIENCY (%)

10

V

INPUT

= 5.5V

V

INPUT

= 4V

V

INPUT

= 3V

FSEL = IN

0

200
100

500
400
300

700
600

800

0 60 8020 40 100 120 140

OUTPUT VOLTAGE DROP

vs. LOAD CURRENT

MAX1680/81TOC01

LOAD CURRENT (mA)

OUTPUT VOLTAGE DROP (mV)

V

INPUT

= 3V

V

INPUT

= 5V

-14

-10

-12

-4

-6

-8

0

-2

2

2.0 3.5 4.02.5 3.0 4.5 5.0 5.5

OSCILLATOR FREQUENCY CHANGE

vs. SUPPLY VOLTAGE

MAX1680/81TOC02

SUPPLY VOLTAGE (V)

OSCILLATOR FREQUENCY CHANGE (%)

MAX1680

MAX1681

-10

-6

-8

-2

-4

2
0

4

8
6

10

-40 0 20-20 40 60 80 100

OSCILLATOR FREQUENCY CHANGE

vs. TEMPERATURE

MAX1680/81TOC03

TEMPERATURE (°C)

OSCILLATOR FREQUENCY CHANGE (%)

MAX1680

MAX1681