Rainbow Electronics MAX662A User Manual

19-0253; Rev 1; 8/94

EVALUATION KIT MANUAL

FOLLOWS DATA SHEET

+12V, 30mA Flash Memory

Programming Supply

_______________General Description

The MAX662A is a regulated +12V, 30mA-output, charge­pump DC-DC converter. It provides the necessary +12V
±5% output to program byte-wide flash memories, and
requires no inductors to deliver a guaranteed 30mA out­put from inputs as low as 4.75V. It fits into less than 0.1in
of board space. The MAX662A is a pin-compatible
upgrade to the MAX662, and is recommended for new
designs. The MAX662A offers lower quiescent and shut­down currents, and guarantees the output current over all
temperature ranges.

The MAX662A is the first charge-pump boost converter to
provide a regulated +12V output. It requires only a few
inexpensive capacitors, and the entire circuit is complete­ly surface-mountable.

A logic-controlled shutdown pin that interfaces directly
with microprocessors reduces the supply current to only

0.5µA. The MAX662A comes in 8-pin narrow SO and DIP
packages.

For higher-current flash memory programming solutions,
refer to the data sheets for the MAX734 (120mA output
current, guaranteed) and MAX732 (200mA output cur­rent, guaranteed) PWM, switch-mode DC-DC converters.
Or, refer to the MAX761 data sheet for a 150mA, PFM
switch-mode DC-DC converter that operates from inputs
as low as 2V.

________________________Applications

+12V Flash Memory Programming Supplies
Compact +12V Op-Amp Supplies
Switching MOSFETs in Low-Voltage Systems
Dual-Output +12V and +20V Supplies

____________________________Features

♦ Regulated +12V ±5% Output Voltage
♦ 4.5V to 5.5V Supply Voltage Range
♦ Fits in 0.1in

2

2

♦ Guaranteed 30mA Output
♦ No Inductor—Uses Only 4 Capacitors
♦ 185µA Quiescent Current
♦ Logic-Controlled 0.5µA Shutdown
♦ 8-Pin Narrow SO and DIP Packages

______________Ordering Information

PART

MAX662ACPA
MAX662ACSA
MAX662AC/D 0°C to +70°C
MAX662AEPA -40°C to +85°C 8 Plastic DIP
MAX662AESA -40°C to +85°C 8 SO
MAX662AMJA -55°C to +125°C 8 CERDIP**

* Dice are tested at TA= +25°C.
** Contact factory for availability and processing to MIL-STD-883.

TEMP. RANGE PIN-PACKAGE

0°C to +70°C
0°C to +70°C

8 Plastic DIP
8 SO
Dice*

MAX662A

__________Typical Operating Circuit

INPUT

4.75V TO 5.5V

4.7µF
V

CC

SHDN

0.22µF 0.22µF

C1+

C1-

V

OUT

MAX662A

C2-

C2+

GND

________________________________________________________________

OUTPUT

12V ±5%

30mA

4.7µF

V

pp

FLASH

MEMORY

__________________Pin Configuration

TOP VIEW

C1-

1

C1+

2
C2­C2+

MAX662A

3

4

DIP/SO

Maxim Integrated Products

Call toll free 1-800-998-8800 for free samples or literature.

SHDN

8

GND

7

V

OUT

6

V

5

CC

1

+12V, 30mA Flash Memory
Programming Supply

ABSOLUTE MAXIMUM RATINGS

VCCto GND ................................................................-0.3V to 6V

SHDN..........................................................-0.3V to (V

Continuous..................................................................50mA

I

OUT

Continuous Power Dissipation (T

Plastic DIP (derate 9.09mW/°C above +70°C) ............727mW

= +70°C)

A

CC

+ 0.3V)

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

CERDIP (derate 8.00mW/°C above +70°C).................640mW

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional

MAX662A

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.

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 3a, VCC= 4.5V to 5.5V, TA= T

Output Voltage

Supply Current

Oscillator Frequency

VCC-to-V

Switch Impedance

OUT

Shutdown Input Threshold

V

OUT

CC

OSC

R

SW

IH
IL

SHDN Pin Current

to T

MIN

MAX

MAX662AC/E

MAX662AM

No load, V
No load, V

SHDN
SHDN

VCC= 5V, I
VCC= 5V, I
VCC= V

SHDN

I

= 30mA

OUT

VCC= 5V, V
VCC= V

SHDN

, unless otherwise noted.)

OUT
OUT

SHDN

__________________________________________Typical Operating Characteristics

(Circuit of Figure 3a, TA = +25°C, unless otherwise noted.)

SUPPLY CURRENT vs. SUPPLY VOLTAGE

300
280

TA = -55°C

260
240

220
200
180
160

SUPPLY CURRENT (µA)

140
120
100

TA = 0°C



4.50 5.25



TA = +25°C

4.75

5.00

SUPPLY VOLTAGE (V)

TA = +125°C

MAX662A-01

OUTPUT VOLTAGE (V)

5.50

OUTPUT VOLTAGE vs. OUTPUT CURRENT

12.6
CONTINUOUS OUTPUT CURRENT MUST 

12.4

NOT EXCEED 50mA ABS MAX LIMIT. 
INTERMITTENT PEAK CURRENTS MAY 

12.2
BE HIGHER.

12.0

11.8

VCC = 4.5V

11.6

VCC = 4.75V

11.4

11.2

11.0

10.8

10.6

VCC = 5.0V

VCC = 5.5V

0 20 60 100

10 30 50 70 90

Operating Temperature Ranges

MAX662AC_A .....................................................0°C to +70°C

MAX662AE_A ..................................................-40°C to +85°C

MAX662AMJA................................................-55°C to +125°C

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

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

CONDITIONS

0mA ≤ I
VCC= 4.75V to 5.5V

0mA ≤ I
0mA ≤ I

VCC= 4.75V to 5.5V
0mA ≤ I

OUT

OUT
OUT

OUT

≤ 30mA,

≤ 20mA
≤ 24mA,

≤ 16mA

11.4 12 12.6

11.4 12 12.6

11.4 12 12.6

11.4 12 12.6

= 0V
= V

CC

= 30mA
= 30mA

= 5V,

MAX662AC/E

12

MAX662AM 1 2.5

2.4V

= 0V

= 5V



MAX662A-02

40 80

OUTPUT CURRENT (mA)

-50 -15 -5
0

EFFICIENCY vs. LOAD CURRENT

100

90

80

70

60

EFFICIENCY (%)

50

40

30

VCC = 5.5V

VCC = 4.5V

VCC = 4.75V

CONTINUOUS OUTPUT CURRENT
MUST NOT EXCEED 50mA ABS MAX
LIMIT. INTERMITTENT PEAK
CURRENTS MAY BE HIGHER.

10 30 50 70 90

0 20 60 100

40 80

LOAD CURRENT (mA)

UNITSMIN TYP MAXSYMBOLPARAMETER

0.4V



VCC = 5.0V

V

µA185 500I
µA0.5 10Shutdown Current

kHz500f

%76Power Efficiency

kΩ

V

µA

MAX662A-03

2 _______________________________________________________________________________________

+12V, 30mA Flash Memory

Programming Supply

_____________________________Typical Operating Characteristics (continued)

(Circuit of Figure 3a, TA= +25°C, unless otherwise noted.)

LOAD-TRANSIENT RESPONSE

A

0mA

B

1ms/div

A: OUTPUT CURRENT, 20mA/div, I
B: OUTPUT VOLTAGE RIPPLE, 100mV/div, V

= 0mA to 30mA

OUT

CC

= 5.0V

_____________________Pin Description

NAME FUNCTION

PIN

1 C1-

2 C1+

3 C2-

4 C2+

5 V

6 V

7 GND Ground

8

SHDN

Negative terminal for the first charge­pump capacitor

Positive terminal for the first charge­pump capacitor

Negative terminal for the second
charge-pump capacitor

Positive terminal for the second
charge-pump capacitor

Supply Voltage

CC

+12V Output Voltage. V

OUT

when in shutdown mode.

Active-high CMOS-logic level
Shutdown Input. SHDN is internally
pulled up to VCC. Connect to GND for
normal operation. In shutdown mode,
the charge pumps are turned off and
V

= VCC.

OUT

OUT

= V

CC

0V

0V

V

CC

C2+

0.22µF

C2-

C1+

0.22µF

C1-

SWITCH CLOSURES SHOWN FOR CHARGE PUMP IN THE TRANSFER MODE
* C3 NOT REQUIRED. FOR MAX662 ONLY.

Figure 1. Block Diagram

LINE-TRANSIENT RESPONSE

1ms/div

A: SUPPLY VOLTAGE, 2V/div, VCC = 4.5V to 5.5V, I
B: OUTPUT VOLTAGE RIPPLE, 200mV/div

C4

4.7µF

S1

S1

S1

S1

V

CC

S2

ERROR
AMP

S2

S2

VREF

MAX662A

OSCILLATOR

GND

OUT

= 30mA

R2

R1

A

B

V

OUT

SHDN

C3*

0.1µF
+12V

C5

4.7µF

MAX662A

_______________________________________________________________________________________ 3

+12V, 30mA Flash Memory
Programming Supply

_______________Detailed Description

The MAX662A provides a regulated 12V output voltage
at 30mA from a 5V ±5% power supply, making it ideal
for flash EEPROM programming applications. It uses
internal charge pumps and external capacitors to gen­erate +12V, eliminating inductors. Regulation is provid­ed by a pulse-skipping scheme that monitors the

MAX662A

output voltage level and turns on the charge pumps
when the output voltage begins to droop.

Figure 1 shows a simplified block diagram of the
MAX662A. When the S1 switches are closed and the
S2 switches are open, capacitors C1 and C2 are
charged up to VCC. The S1 switches are then opened
and the S2 switches are closed so that capacitors C1
and C2 are connected in series between VCCand
V

. This performs a voltage tripling function. A pulse-

OUT

skipping feedback scheme adjusts the output voltage
to 12V ±5%. The efficiency of the MAX662A with VCC=
5V and I
Efficiency vs. Load Current graph in the

= 30mA is typically 76%. See the

OUT

Operating Characteristics

During one oscillator cycle, energy is transferred from
the charge-pump capacitors to the output filter capaci­tor and the load. The number of cycles within a given
time frame increases as the load current increases or
as the input supply voltage decreases. In the limiting
case, the charge pumps operate continuously, and the
oscillator frequency is nominally 500kHz.

5V
0V

12V

5V

CIRCUIT OF FIGURE 3, VCC = 5V, I

Figure 2. MAX662A Exiting Shutdown

Operating Principle

.

200µs/div

= 200µA

OUT

Typical

SHDN

V

OUT

The MAX662A enters shutdown mode when SHDN is a
logic high. SHDN is a TTL/CMOS-compatible input sig­nal that is internally pulled up to VCC. In shutdown
mode, the charge-pump switching action is halted and
VINis connected to V
entering shutdown, V
13ms. Connect SHDN to ground for normal operation.
When VCC= 5V, it takes typically 400µs for the output
to reach 12V after SHDN goes low (Figure 2).

through a 1kΩ switch. When

OUT

declines to VCCin typically

OUT

__________Applications Information

Shutdown Mode

The MAX662A is a 100%-compatible upgrade of the
MAX662. The MAX662A does not require capacitor C3,
although its presence does not affect performance.

The capacitance values of the charge-pump capacitors
C1 and C2 are critical. Use ceramic or tantalum capaci­tors in the 0.22µF to 1.0µF range. For applications requir­ing operation over extended and/or military temperature
ranges, use 1.0µF tantalum capacitors for C1 and C2
(Figure 3b).

The type of input bypass capacitor (C4) and output filter
capacitor (C5) affects performance. Tantalums, ceramics
or aluminum electrolytics are suggested. For smallest size,
use Sprague 595D475X9016A7 surface-mount capacitors,
which are 3.51mm x 1.81mm. For lowest ripple, use low­ESR through-hole ceramic or tantalum capacitors. For low­est cost, use aluminum electrolytic or tantalum capacitors.

Figure 3a shows the component values for proper opera­tion over the commercial temperature range using mini­mum board space. The input bypass capacitor (C4) and
output filter capacitor (C5) should both be at least 4.7µF
when using Sprague’s miniature 595D series of tantalum
chip capacitors. Figure 3b shows the suggested compo­nent values for applications over extended and/or mili­tary temperature ranges.

The values of C4 and C5 can be reduced to 2µF and
1µF, respectively, when using ceramic capacitors. If
using aluminum electrolytics, choose capacitance values
of 10µF or larger for C4 and C5. Note that as V
increases above 5V and the output current decreases,
the amount of ripple at V
oscillator frequency combined with the higher input volt­age. Increase the input and output bypass capacitance
to reduce output ripple.

Table 1 lists various capacitor suppliers.

Compatibility with MAX662

Capacitor Selection

Charge-Pump Capacitors, C1 and C2

Input and Output Capacitors, C4 and C5

CC

increases due to the slower

OUT

4 _______________________________________________________________________________________

+12V, 30mA Flash Memory

Programming Supply

Table 1. Capacitor Suppliers

Supplier Phone Number Fax Number Capacitor Capacitor Type*

Murata Erie [phone] [phone]

Sprague Electric

[phone]
[phone]

[phone]
[phone]

*Note: (SM) denotes surface-mount component, (TH) denotes through-hole component.

Layout is critical, due to the MAX662A’s high oscillator
frequency. Good layout ensures stability and helps
maintain the output voltage under heavy loads. For best
performance, use very short connections to the capaci­tors. The order of importance is: C4, C5, C1, C2.

The circuit of Figure 3a is a +12V ±5% 30mA flash
EEPROM programming power supply. A microproces­sor controls the programming voltage via the SHDN
pin. When SHDN is low, the output voltage (which is
connected to the flash memory VPPsupply-voltage pin)
rises to +12V to facilitate programming the flash memo-

V

IN

4.75V TO 5.5V



V

OUT

+12V ±5%

AT 30mA

0.22µF

4.7µF

4.7µF

3

C2

C4

C5

C2-

MAX662A

4

C2+

5

V

CC

6

V

OUT

C1+

C1-

SHDN

GND

2

1

8

7

C1

0.22µF


PROGRAMMING
CONTROL
DIRECT FROM
µP

ry. When SHDN is high, the output voltage is connected
to VINthrough an internal 1kΩ resistor.

Figure 3a. Flash EEPROM Programming Power Supply for
Commercial Temperature Range Applications

Two MAX662As can be placed in parallel to increase
output drive capability. The VCC, V
can be paralleled, reducing pin count. Use a single
bypass capacitor and a single output filter capacitor
with twice the capacitance value if the two devices can

C1+

C1-

SHDN

GND

2

1

8

7

*C1

1.0µF


PROGRAMMING
CONTROL
DIRECT FROM
µP

V

IN

4.75V TO 5.5V



V

OUT

+12V ±5%

AT 30mA

3

*C2

1.0µF

22µF

*C5

22µF

*C4

C2-

MAX662A

4

C2+

5

V

CC

6

V

OUT

*SPRAGUE 595D SERIES OR EQUIVALENT

Figure 3b. Flash EEPROM Programming Power Supply for
Extended and/or Military Temperature Range Applications

be placed close to each other. If the MAX662As cannot
be placed close together, use separate bypass and
output capacitors. The amount of output ripple
observed will determine whether single input bypass
and output filter capacitors can be used. Under certain
conditions, one device may supply the total output cur­rent. Therefore, regardless of the number of devices in
parallel, the maximum continuous current must not
exceed 50mA.

Using the charge-pump voltage-doubler circuit of
Figure 4, the MAX662A can produce a +20V supply
from a single +5V supply. Figure 5 shows the current
capability of the +20V supply.

GRM42-6Z5U224M50 0.22µF Ceramic (SM)
RPE123Z5U105M50V 1.0µF Ceramic (TH)
595D475X9016A7 4.7µF Tantalum (SM)
595D105X9016A7 1.0µF Tantalum (SM)

Layout Considerations

Flash EEPROM Applications

Paralleling Devices

12V and 20V Dual-Output Power Supply

, and GND pins

OUT

MAX662A

_______________________________________________________________________________________ 5

+12V, 30mA Flash Memory
Programming Supply

C1+

C1-

SHDN

GND

V

2

0.22µF


1

8
7

5

CC

V

IN

5V ±5%

2µF

= 

0.22µF

20V

OUTPUT

1µF

1µF

1N5818

OUTPUT

1N5818

1µF

12V

MAX662A

3

4

6

C2-

MAX662A

C2+

V

OUT



20.0
CIRCUIT OF FIGURE 4

= 4.75V

V

CC

= +25°C

T

19.2

18.4

17.6

20V OUTPUT VOLTAGE (V)

16.8

16.0

A

WITH +12V OUTPUT
UNLOADED

WITH 34mA LOAD
ON +12V OUTPUT

15

510 25

030

20V OUTPUT CURRENT (mA)

20 35 40

MAX662AFIG 5

Figure 4. +12V and +20V Dual Supply from a +5V Input

Figure 5. +20V Supply Output Current Capability

___________________Chip Topography

C2- C1+

C2+

0.086"

(2.184mm)

V

CC

V

OUT

0.086"

(2.184mm)

C1-

SHDN

GND

TRANSISTOR COUNT: 225
SUBSTRATE CONNECTED TO V

6 _______________________________________________________________________________________

OUT