Maxim MAX1641EEE, MAX1641C-D, MAX1640C-D Datasheet

_______________General Description

The MAX1640/MAX1641 CMOS, adjustable-output,
switch-mode current sources operate from a +5.5V to
+26V input, and are ideal for microprocessor-controlled
battery chargers. Charging current, maximum output
voltage, and pulse-trickle charge are programmed with
external resistors. Programming the off-time modifies
the switching frequency, suppressing undesirable har­monics in noise-sensitive circuits. The MAX1640’s high­side current sensing allows the load to connect directly
to ground, eliminating ground-potential errors. The
MAX1641 incorporates a low-side current sense.

The MAX1640/MAX1641 step-down pulse-width-modu­lation (PWM) controllers use an external P-channel
MOSFET switch and an optional, external N-channel
MOSFET synchronous rectifier for increased efficiency.
An internal low-dropout linear regulator provides power
for the internal reference and circuitry as well as the
gate drive for the N-channel synchronous rectifier.

The MAX1640/MAX1641 are available in space-saving,
16-pin narrow QSOP packages.

________________________Applications

Battery-Powered Equipment

Laptop, Notebook, and Palmtop Computers
Handy Terminals

Portable Consumer Products

Cordless Phones
Cellular Phones
PCS Phones

Backup Battery Charger

____________________________Features

♦ 95% Efficiency
♦ +5.5V to +26V Input Supply Range
♦ 2V to 24V Adjustable-Output Voltage Range
♦ 100% Maximum Duty Cycle (Low Dropout)
♦ Up to 500kHz PWM Operation
♦ Optional Synchronous Rectifier
♦ 16-Pin QSOP Package
♦ Current-Sense Accuracy: 2% (MAX1641)

5.3% (MAX1640)

MAX1640/MAX1641

Adjustable-Output, Switch-Mode

Current Sources with Synchronous Rectifier

________________________________________________________________

Maxim Integrated Products

1

__________________Pin Configuration

16
15
14
13
12
11
10

9

1
2
3
4
5
6
7
8

LDOL IN

LDOH
PDRV
NDRV
PGND
CS+
CS­GND

TOP VIEW

MAX1640
MAX1641

QSOP

TOFF

D1

REF

D0

CC

SET

TERM

19-1245; Rev 0; 7/97

PART

MAX1640C/D

MAX1640EEE
MAX1641C/D

0°C to +70°C

-40°C to +85°C

0°C to +70°C

TEMP. RANGE PIN-PACKAGE

Dice*
16 QSOP
Dice*

______________Ordering Information

*

Dice are specified at TA= +25°C, DC parameters only.

MAX1641EEE -40°C to +85°C 16 QSOP

IN LDOH

PDRV

NDRV

P

PGND

CS+

CS-

TERM

LDOLGND

OUT

D0

V

IN

= +5.5V TO +26V

D1
TOFF

R

TOFF

REF

SET

CC

MAX1640

__________Typical Operating Circuit

EVALUATION KIT

AVAILABLE

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

MAX1640/MAX1641

Adjustable-Output, Switch-Mode
Current Source with Synchronous Rectifier

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN= +12V, V

OUT

= 6V, Circuit of Figure 2, TA= 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.

Note 1: This ratio is generated by a 1:8 clock divider and is not an error source for current calculations.

IN to GND...............................................................-0.3V to +28V

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

LDOL to GND...........................................................-0.3V to +6V

PDRV to GND .............................. (V

LDOH

- 0.3V) to (VIN+ 0.3V)

NDRV to GND.........................................-0.3V to (V

LDOL

+ 0.3V)

TOFF, REF, SET, TERM, CC to GND ......-0.3V to (V

LDOL

+ 0.3V)

D0, D1 to GND .........................................................-0.3V to +6V

CS+, CS- to GND ...................................................-0.3V to +28V

PGND to GND.....................................................................±0.3V

Continuous Power Dissipation (TA = +70°C)

QSOP (derate 8.30mW/°C above +70°C)................... 667mW

Operating Temperature Range

MAX164_EEE...................................................-40°C to +85°C

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

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

I

REF

= 0 to 50µA

D0 = D1 = low

D0 = D1 = low (off mode)

D0 or D1 = high

V

OUT

= 2V to 24V

VIN= V

OUT

+ 0.5V to 26V

MAX1641

MAX1641

MAX1640

VIN= 5.5V to 26V, I

LOAD

= 0 to 20mA

VIN= 5.5V to 26V, I

LOAD

= 0 to 20mA

MAX1640

CONDITIONS

µA1V

SET

Input Current

mV4 10Reference Load Regulation

V1.96 2.00 2.04V

REF

Reference Voltage

V4.05 4.20 4.35V

LDOL

Undervoltage Lockout

µA1Output Current in Off Mode

500

mA2 4

Quiescent VINSupply Current

0.1

%/V

0.1 0.4

Output Current Compliance

%/V0.03Current-Sense Line Regulation

34 37.5 41

mV

36 42 48

147 150 153

mV

142 150 158

Full-Scale Current-Sense
Threshold

V

VIN- VIN- VIN-

5.5 5.0 4.5

V

LDOH

Linear-Regulator Output
Voltage, VINReferenced

V4.5 5.0 5.5V

LDOL

Linear-Regulator Output
Voltage, Ground Referenced

UNITSMIN TYP MAXSYMBOLPARAMETER

V5.5 26V

IN

Input Voltage Range

FET Drive Output Resistance PFET and NFET drive 12 Ω
Off-Time Range 1 10 µs
Off-Time Accuracy R

TOFF

= 62kΩ 1.7 2.2 2.7 µs

Pulse-Trickle Mode Duty-Cycle
Period

D0 = low, D1 = high, R

TOFF

= 100kΩ 27 33 40 ms

Pulse-Trickle Mode Duty Cycle
(Note 1)

D0 = low, D1 = high, R

TOFF

= 100kΩ 12.5 %

Quarter-Scale Current-Sense
Threshold

MAX1640
MAX1641

µA

MAX1640/MAX1641

Adjustable-Output, Switch-Mode

Current Source with Synchronous Rectifier

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS

(VIN= +12V, V

OUT

= 6V, Circuit of Figure 2, TA= -40°C to +85°C, unless otherwise noted.)

I

REF

= 0 to 50µA

V

OUT

= 2V to 24V (MAX1640)

D0 = D1 = low

D0 or D1 = high

FET Drive Output Resistance

MAX1641

MAX1640

VIN= 5.5V to 26V,
I

LOAD

= 0 to 20mA

VIN= 5.5V to 26V,
I

LOAD

= 0 to 20mA

MAX1640

CONDITIONS

µA1V

SET

Input Current

mV10Reference Load Regulation

V1.94 2.06V

REF

Reference Voltage

V4.0 4.4V

LDOL

Undervoltage Lockout

µA1Output Current in Off Mode

mA4Quiescent VINSupply Current

%/V0.4Output Current Compliance

mV

34 48

Quarter-Scale Current-Sense
Threshold

12 Ω

Off-Time Range

V5.5 26V

IN

Input Voltage Range

1.5 8 µs

Off-Time Accuracy R

TOFF

= 62kΩ 1.5 2.5 µs

146 154

Pulse-Trickle Mode Duty-Cycle
Period

mV

141 159

Full-Scale Current-Sense
Threshold

V

VIN- VIN-

5.5 4.5

V

LDOH

Linear-Regulator Output
Voltage, VINReferenced

D0 = low, D1 = high, R

TOFF

= 50kΩ 25 42 ms

V4.5 5.5V

LDOL

Linear-Regulator Output
Voltage, Ground Referenced

UNITSMIN TYP MAXSYMBOLPARAMETER

PWM Maximum Duty Cycle 100 %
Input Low Voltage V

IL

D0, D1 0.8 V

Input High Voltage V

IH

D0, D1 2.4 V

Input Leakage Current I

IN

D0, D1 ±1 µA

33 42MAX1641

ELECTRICAL CHARACTERISTICS (continued)

(VIN= +12V, V

OUT

= 6V, Circuit of Figure 2, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)

CONDITIONS UNITSMIN TYP MAXSYMBOLPARAMETER

PWM Maximum Duty Cycle 100 %
Input Low Voltage V

IL

D0, D1 0.8 V

Input High Voltage V

IH

D0, D1 2.4 V

Input Leakage Current I

IN

D0, D1 ±1 µA

MAX1640/MAX1641

Adjustable-Output, Switch-Mode
Current Source with Synchronous Rectifier

4 _______________________________________________________________________________________

0.45

0.51

0.49

0.47

0.53

0.55

0.57

0.59

0.61

0.63

0.65

4 128 16 20 24 28

OFF-MODE SUPPLY CURRENT

(NO-LOAD)

MAX1640/41-TOC07

INPUT VOLTAGE (V)

OFF-MODE SUPPLY CURRENT (mA)

TA = -40°C

TA = +25°C

TA = +85°C

10,000

1

0 50 100 150 200 250 300 350 400

SWITCHING FREQUENCY vs. R

TOFF

MAX1640/41 TOC 08

T

OFF

(kΩ)

SWITCHING FREQUENCY (kHz)

10

100

1000

V

OUT

= +3V

V

OUT

= +6V

__________________________________________Typical Operating Characteristics

(Circuit of Figure 2, TA = +25°C, unless otherwise noted.)

40

60

50

80

70

90

100

2 6 8 104 12 14 16 18 20 22 24

EFFICIENCY vs. OUTPUT VOLTAGE

MAX1640/41-TOC01

OUTPUT VOLTAGE (V)

EFFICIENCY (%)

VIN = 12V

VIN = 18V

VIN = 26V

1.460

1.470

1.480

1.490

1.500

1.510

4 128 16 20 24 28

MAX1640

OUTPUT CURRENT vs. INPUT VOLTAGE

MAX1640/41 TOC02

INPUT VOLTAGE (V)

OUTPUT CURRENT (A)

TA = -40°C

(V

OUT

= 4V)

TA = +25°C

TA = +85°C

1.450

1.470

1.460

1.490

1.480

1.500

1.510

2 6 8 104 12 14 16 18 20 22 24

MAX1640

OUTPUT CURRENT vs. OUTPUT VOLTAGE

MAX1640/41-TOC03

OUTPUT VOLTAGE (V)

OUTPUT CURRENT (A)

TA = -40°C

TA = +85°C

TA = +25°C

1.450

1.475

1.500

1.525

1.550

4 128 16 20 24 28

MAX1641

OUTPUT CURRENT vs. INPUT VOLTAGE

MAX1640/41 TOC04

INPUT VOLTAGE (V)

OUTPUT CURRENT (A)

TA = -40°C

(V

OUT

= 4V)

TA = +25°C

TA = +85°C

1.420

1.460

1.440

1.500

1.480

1.540

1.520

1.560

2 6 8 104 12 14 16 18 20 22 24

MAX1641

OUTPUT CURRENT vs. OUTPUT VOLTAGE

MAX1640/41-TOC05

V

OUT

(V)

OUTPUT CURRENT (A)

TA = -40°C

TA = +25°C

TA = +85°C

1.5

1.9

1.7

2.1

2.3

2.5

2.7

2.9

4 128 16 20 24 28

QUIESCENT CURRENT

vs. INPUT VOLTAGE (NO-LOAD)

MAX1640/41-TOC06

INPUT VOLTAGE (V)

QUIESCENT CURRENT (mA)

TA = -40°C

TA = +25°C

TA = +85°C

A: OUTPUT CURRENT, D1 = D0 = 1 1A/div

V

LOAD

= 3V

B: INPUT VOLTAGE, 10V/div

LINE-TRANSIENT RESPONSE

A

B

0A

0V

2ms/div

MAX1640/41 TOC 09