Maxim MAX662AC/D 12v, 30ma flash memory programming supply Datasheet

19-0253; Rev 1; 8/94
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+12V, 30mA Flash Memory
Programming Supply
________________________Applications
____________________________Features
♦ Regulated +12V ±5% Output Voltage
♦ 4.5V to 5.5V Supply Voltage Range
♦ Fits in 0.1in2
♦ 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
TEMP. RANGE
MAX662ACPA
0°C to +70°C
PIN-PACKAGE
8 Plastic DIP
MAX662ACSA
MAX662AC/D
MAX662AEPA
MAX662AESA
MAX662AMJA
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
8 SO
Dice*
8 Plastic DIP
8 SO
8 CERDIP**
* Dice are tested at TA = +25°C.
** Contact factory for availability and processing to MIL-STD-883.
+12V Flash Memory Programming Supplies
Compact +12V Op-Amp Supplies
Switching MOSFETs in Low-Voltage Systems
Dual-Output +12V and +20V Supplies
__________Typical Operating Circuit
INPUT
4.75V TO 5.5V
TOP VIEW
4.7µF
OUTPUT
12V ±5%
30mA
VCC
SHDN
Vpp
VOUT
FLASH
MEMORY
MAX662A
0.22µF
C1+
C1-
__________________Pin Configuration
C2-
GND
0.22µF
4.7µF
C1- 1
8
SHDN
C1+ 2
7
GND
6
VOUT
5
VCC
C2- 3
MAX662A
C2+ 4
C2+
DIP/SO
________________________________________________________________ Maxim Integrated Products
Call toll free 1-800-998-8800 for free samples or literature.
1
MAX662A
_______________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 0.1in2
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.
ABSOLUTE MAXIMUM RATINGS
VCC to GND ................................................................-0.3V to 6V
SHDN..........................................................-0.3V to (VCC + 0.3V)
IOUT Continuous..................................................................50mA
Continuous Power Dissipation (TA = +70°C)
Plastic DIP (derate 9.09mW/°C above +70°C) ............727mW
SO (derate 5.88mW/°C above +70°C) .........................471mW
CERDIP (derate 8.00mW/°C above +70°C) .................640mW
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
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.
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 3a, VCC = 4.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MAX662AC/E
Output Voltage
VOUT
MAX662AM
Supply Current
Shutdown Current
Oscillator Frequency
Power Efficiency
ICC
RSW
Shutdown Input Threshold
VIH
VIL
MIN
TYP
MAX
0mA ≤ IOUT ≤ 30mA,
VCC = 4.75V to 5.5V
11.4
12
12.6
0mA ≤ IOUT ≤ 20mA
11.4
12
12.6
0mA ≤ IOUT ≤ 24mA,
VCC = 4.75V to 5.5V
11.4
12
12.6
0mA ≤ IOUT ≤ 16mA
11.4
12
12.6
185
0.5
500
76
1
1
500
10
UNITS
V
No load, VSHDN = 0V
No load, VSHDN = VCC
VCC = 5V, IOUT = 30mA
VCC = 5V, IOUT = 30mA
MAX662AC/E
VCC = VSHDN = 5V,
IOUT = 30mA
MAX662AM
fOSC
VCC-to-VOUT Switch Impedance
µA
µA
kHz
%
2
2.5
2.4
VCC = 5V, VSHDN = 0V
VCC = VSHDN = 5V
SHDN Pin Current
-50
-15
0
0.4
-5
kΩ
V
µA
__________________________________________Typical Operating Characteristics
(Circuit of Figure 3a, TA = +25°C, unless otherwise noted.)
OUTPUT VOLTAGE (V)
12.2
240
220
200
TA = 0°C
180
TA = +25°C
160
TA = +125°C
140
120
12.0
11.8
VCC = 4.5V
11.6
VCC = 4.75V
11.4
VCC = 5.0V
11.2
VCC = 5.5V
11.0
4.75
5.00
5.25
SUPPLY VOLTAGE (V)
5.50
VCC = 5.5V
80
70
VCC = 4.5V
VCC = 4.75V
VCC = 5.0V
60
50
CONTINUOUS OUTPUT CURRENT
MUST NOT EXCEED 50mA ABS MAX
LIMIT. INTERMITTENT PEAK
CURRENTS MAY BE HIGHER.
30
10.6
4.50
90
40
10.8
100
2
12.4
EFFICIENCY vs. LOAD CURRENT
100
MAX662A-03
TA = -55°C
CONTINUOUS OUTPUT CURRENT MUST
NOT EXCEED 50mA ABS MAX LIMIT.
INTERMITTENT PEAK CURRENTS MAY
BE HIGHER.
EFFICIENCY (%)
MAX662A-01
280
260
OUTPUT VOLTAGE vs. OUTPUT CURRENT
12.6
MAX662A-02
SUPPLY CURRENT vs. SUPPLY VOLTAGE
300
SUPPLY CURRENT (µA)
MAX662A
+12V, 30mA Flash Memory
Programming Supply
0
10 20 30 40 50 60 70 80 90 100
OUTPUT CURRENT (mA)
0
10 20 30 40 50 60 70 80 90 100
LOAD CURRENT (mA)
_______________________________________________________________________________________
+12V, 30mA Flash Memory
Programming Supply
LINE-TRANSIENT RESPONSE
LOAD-TRANSIENT RESPONSE
A
A
0mA
0V
B
B
0V
1ms/div
1ms/div
A: OUTPUT CURRENT, 20mA/div, IOUT = 0mA to 30mA
B: OUTPUT VOLTAGE RIPPLE, 100mV/div, VCC = 5.0V
_____________________Pin Description
A: SUPPLY VOLTAGE, 2V/div, VCC = 4.5V to 5.5V, IOUT = 30mA
B: OUTPUT VOLTAGE RIPPLE, 200mV/div
VCC
C4
4.7µF
PIN
NAME
FUNCTION
1
C1-
Negative terminal for the first chargepump capacitor
C1+
Positive terminal for the first chargepump capacitor
2
3
C2-
Negative terminal for the second
charge-pump capacitor
4
C2+
Positive terminal for the second
charge-pump capacitor
5
VCC
Supply Voltage
6
VOUT
+12V Output Voltage. VOUT = VCC
when in shutdown mode.
7
GND
Ground
SHDN
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
VOUT = VCC.
8
VCC
C2+
S1
C3*
0.1µF
S2
0.22µF
VOUT
C2-
R2
S1
ERROR
AMP
+12V
C5
4.7µF
R1
S2
C1+
VREF
S1
0.22µF
SHDN
S2
C1-
MAX662A
S1
OSCILLATOR
GND
SWITCH CLOSURES SHOWN FOR CHARGE PUMP IN THE TRANSFER MODE
* C3 NOT REQUIRED. FOR MAX662 ONLY.
Figure 1. Block Diagram
_______________________________________________________________________________________
3
MAX662A
_____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 3a, TA = +25°C, unless otherwise noted.)
MAX662A
+12V, 30mA Flash Memory
Programming Supply
_______________Detailed Description
Operating Principle
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
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 V CC and
VOUT. This performs a voltage tripling function. A pulseskipping feedback scheme adjusts the output voltage
to 12V ±5%. The efficiency of the MAX662A with VCC =
5V and I OUT = 30mA is typically 76%. See the
Efficiency vs. Load Current graph in the Typical
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
SHDN
0V
12V
VOUT
5V
200µs/div
CIRCUIT OF FIGURE 3, VCC = 5V, IOUT = 200µA
Figure 2. MAX662A Exiting Shutdown
4
Shutdown Mode
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 V CC. In shutdown
mode, the charge-pump switching action is halted and
VIN is connected to VOUT through a 1kΩ switch. When
entering shutdown, VOUT declines to VCC in typically
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).
__________Applications Information
Compatibility with MAX662
The MAX662A is a 100%-compatible upgrade of the
MAX662. The MAX662A does not require capacitor C3,
although its presence does not affect performance.
Capacitor Selection
Charge-Pump Capacitors, C1 and C2
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).
Input and Output Capacitors, C4 and C5
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 CC
increases above 5V and the output current decreases,
the amount of ripple at VOUT increases due to the slower
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.
_______________________________________________________________________________________
+12V, 30mA Flash Memory
Programming Supply
Supplier
Murata Erie
Phone Number
Fax Number
(814) 237-1431
(814) 238-0490
(603) 224-1961
(207) 324-4140
Sprague Electric
(603) 224-1430
(207) 324-7223
Capacitor
MAX662A
Table 1. Capacitor Suppliers
Capacitor Type*
GRM42-6Z5U224M50
0.22µF Ceramic (SM)
RPE123Z5U105M50V
1.0µF Ceramic (TH)
595D475X9016A7
4.7µF Tantalum (SM)
595D105X9016A7
1.0µF Tantalum (SM)
*Note: (SM) denotes surface-mount component, (TH) denotes through-hole component.
Layout Considerations
3
C2
0.22µF
VIN
4.75V TO 5.5V
VOUT
+12V ±5%
AT 30mA
4
5
C4
4.7µF
6
C5
4.7µF
C2-
C1+
MAX662A
C2+
C1-
VCC
SHDN
VOUT
GND
2
1
C1
0.22µF
Flash EEPROM Applications
8
7
PROGRAMMING
CONTROL
DIRECT FROM
µP
Figure 3a. Flash EEPROM Programming Power Supply for
Commercial Temperature Range Applications
3
*C2
1.0µF
VIN
4.75V TO 5.5V
VOUT
+12V ±5%
AT 30mA
4 C2+
5
*C4
22µF
*C5
22µF
C2-
6
C1+
MAX662A
C1-
VCC
SHDN
VOUT
GND
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.
2
1
8
7
*C1
1.0µF
PROGRAMMING
CONTROL
DIRECT FROM
µP
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 VPP supply-voltage pin)
rises to +12V to facilitate programming the flash memory. When SHDN is high, the output voltage is connected
to VIN through an internal 1kΩ resistor.
Paralleling Devices
Two MAX662As can be placed in parallel to increase
output drive capability. The VCC, VOUT, and GND pins
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
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.
12V and 20V Dual-Output Power Supply
*SPRAGUE 595D SERIES OR EQUIVALENT
Figure 3b. Flash EEPROM Programming Power Supply for
Extended and/or Military Temperature Range Applications
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.
_______________________________________________________________________________________
5
20.0
C2-
0.22µF
4
C1+
C2+
1µF
20V
OUTPUT
1µF
1N5818
0.22µF
MAX662A
C1SHDN
12V
OUTPUT
GND
6
VOUT
VCC
CIRCUIT OF FIGURE 4
VCC = 4.75V
TA = +25°C
2
20V OUTPUT VOLTAGE (V)
3
1
8
7
5
VIN =
5V ±5%
MAX662AFIG 5
MAX662A
+12V, 30mA Flash Memory
Programming Supply
19.2
WITH +12V OUTPUT
UNLOADED
18.4
WITH 34mA LOAD
ON +12V OUTPUT
17.6
16.8
1N5818
1µF
2µF
16.0
0
5
10
15
20
25
30
35
40
20V OUTPUT CURRENT (mA)
Figure 4. +12V and +20V Dual Supply from a +5V Input
Figure 5. +20V Supply Output Current Capability
___________________Chip Topography
C2+
C2- C1+
0.086"
(2.184mm)
C1V CC
SHDN
V OUT
0.086"
(2.184mm)
GND
TRANSISTOR COUNT: 225
SUBSTRATE CONNECTED TO VOUT
6
_______________________________________________________________________________________
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