TC7660
Charge Pump DC-to-DC Voltage Converter
Features
Wide Input Voltage Range: +1.5V to +10V
Efficient Voltage Conversion (99.9%, typ)
Excellent Power Efficiency (98%, typ)
Low Power Consumption: 80 µA (typ) @ V
IN
= 5V
Low Cost and Easy to Use
- Only Two External Capacitors Required
• Available in 8-Pin Small Outline (SOIC), 8-Pin
PDIP and 8-Pin CERDIP Packages
• Improved ESD Protection (3 kV HBM)
• No External Diode Required for High-Voltage
Operation
•
•
•
•
•
Package Types
PDIP/CERDIP/SOIC
NC
1
8
V
+
OSC
LOW
VOLTAGE (LV)
V
OUT
CAP
+
2
GND 3
CAP
-
4
TC7660
7
6
5
General Description
The TC7660 device is a pin-compatible replacement
for the industry standard 7660 charge pump voltage
converter. It converts a +1.5V to +10V input to a corre-
sponding -1.5V to -10V output using only two low-cost
capacitors, eliminating inductors and their associated
cost, size and electromagnetic interference (EMI).
The on-board oscillator operates at a nominal fre-
quency of 10 kHz. Operation below 10 kHz (for lower
supply current applications) is possible by connecting
an external capacitor from OSC to ground.
The TC7660 is available in 8-Pin PDIP, 8-Pin Small
Outline (SOIC) and 8-Pin CERDIP packages in
commercial and extended temperature ranges.
Applications
•
•
•
•
RS-232 Negative Power Supply
Simple Conversion of +5V to ±5V Supplies
Voltage Multiplication V
OUT
= ± n V
+
Negative Supplies for Data Acquisition Systems
and Instrumentation
Functional Block Diagram
V
+
CAP
+
8
2
OSC
LV
7
6
RC
Oscillator
2
Voltage
Level
Translator
4
CAP-
5
Internal
Internal
Voltage
Voltage
Regulator
Regulator
V
OUT
TC7660
3
GND
Logic
Network
2002-2011 Microchip Technology Inc.
DS21465C-page 1
TC7660
1.0
ELECTRICAL
CHARACTERISTICS
*
Notice:
Stresses above those listed under “Maximum Rat-
ings” may cause permanent damage to the device. This is a
stress rating only and functional operation of the device at
those or any other conditions above those indicated in the
operational sections of this specification is not intended. Expo-
sure to maximum rating conditions for extended periods may
affect device reliability.
I
S
I
L
V
+
(+5V)
R
L
V
OUT
C
2
+ 10 µF
Absolute Maximum Ratings*
Supply Voltage .............................................................+10.5V
LV and OSC Inputs Voltage:
(Note
1)
.............................................. -0.3V to V
SS
for V
+
< 5.5V
..................................... (V
+
– 5.5V) to (V
+
) for V
+
> 5.5V
Current into LV ......................................... 20 µA for V
+
> 3.5V
Output Short Duration (V
SUPPLY
5.5V)............... Continuous
Package Power Dissipation: (T
A
70°C)
8-Pin CERDIP ....................................................800 mW
8-Pin PDIP .........................................................730 mW
8-Pin SOIC .........................................................470 mW
Operating Temperature Range:
C Suffix.......................................................0°C to +70°C
I Suffix .....................................................-25°C to +85°C
E Suffix ....................................................-40°C to +85°C
M Suffix .................................................-55°C to +125°C
Storage Temperature Range .........................-65°C to +160°C
ESD protection on all pins (HBM) ................... .............. 3 kV
Maximum Junction Temperature ........... ....................... 150°C
1
C
1
+
10 µF
2
3
4
TC7660
8
7
6
5
C
OSC
FIGURE 1-1:
TC7660 Test Circuit.
ELECTRICAL SPECIFICATIONS
Electrical Characteristics:
Unless otherwise noted, specifications measured over operating temperature range with V
+
= 5V,
C
OSC
= 0, refer to test circuit in
Figure 1-1.
Parameters
Supply Current
Supply Voltage Range, High
Supply Voltage Range, Low
Output Source Resistance
Sym
Min
—
3.0
1.5
—
—
—
—
—
—
Oscillator Frequency
Power Efficiency
Voltage Conversion Efficiency
Oscillator Impedance
Typ
80
—
—
70
—
—
104
150
160
10
98
99.9
1.0
100
Max
180
10
3.5
100
120
130
150
300
600
—
—
—
—
—
kHz
%
%
M
k
Units
µA
V
V
R
L
=
Min
T
A
Max,
R
L
= 10 k, LV Open
Min
T
A
Max,
R
L
= 10 k, LV to GND
I
OUT
=20 mA, T
A
= +25°C
I
OUT
=20 mA, T
A
+70°C (C Device)
I
OUT
=20 mA, T
A
+85°C (E and I Device)
I
OUT
=20 mA, T
A
+125°C (M Device)
V
+
= 2V, I
OUT
= 3 mA, LV to GND
0°C
T
A
+70°C
V
+
= 2V, I
OUT
= 3 mA, LV to GND
-55°C
T
A
+125°C (M Device)
Pin 7 open
R
L
= 5 k
R
L
=
V
+
= 2V
V
+
= 5V
Conditions
I
+
V
+H
V
+L
R
OUT
f
OSC
P
EFF
V
OUTEFF
Z
OSC
—
95
97
—
—
Note 1:
Destructive latch-up may occur if voltages greater than V
+
or less than GND are supplied to any input pin.
DS21465C-page 2
2002-2011 Microchip Technology Inc.
TC7660
2.0
Note:
TYPICAL PERFORMANCE CURVES
The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
Note:
Unless otherwise indicated, C
1
= C
2
= 10 µF, ESR
C1
= ESR
C2
= 1
,
T
A
= 25°C. See
Figure 1-1.
12
POWER CONVERSION EFFICIENCY (%)
100
98
96
94
92
90
88
86
84
82
V+ = +5V
80
100
1k
OSCILLATOR FREQUENCY (Hz)
I
OUT
= 15 mA
I
OUT
= 1 mA
10
SUPPLY VOLTAGE (V)
8
6
4
2
SUPPLY VOLTAGE RANGE
0
-55
-25
0
+25 +50 +75 +100 +125
TEMPERATURE (°C)
10k
FIGURE 2-1:
Temperature.
10k
Operating Voltage vs.
FIGURE 2-4:
Power Conversion
Efficiency vs. Oscillator Frequency.
500
OUTPUT SOURCE RESISTANCE (Ω)
OUTPUT SOURCE RESISTANCE (Ω)
I
OUT
= 1 mA
450
400
200
150
V + = +2V
100
50
0
-55
V + = +5V
1k
100Ω
10Ω
0
1
2
3
4
5
6
SUPPLY VOLTAGE (V)
7
8
-25
0
+25 +50 +75 +100 +125
TEMPERATURE (°C)
FIGURE 2-2:
Output Source Resistance
vs. Supply Voltage.
10k
OSCILLATOR FREQUENCY (Hz)
FIGURE 2-5:
vs. Temperature.
20
OSCILLATOR FREQUENCY (kHz)
Output Source Resistance
V+ = +5V
V+ = +5V
18
16
14
12
10
8
6
-55
1k
100
10
1
10
100
1000
OSCILLATOR CAPACITANCE (pF)
10k
-25
0
+25 +50 +75 +100 +125
TEMPERATURE (°C)
FIGURE 2-3:
Frequency of Oscillation vs.
Oscillator Capacitance.
FIGURE 2-6:
Unloaded Oscillator
Frequency vs. Temperature.
2002-2011 Microchip Technology Inc.
DS21465C-page 3
TC7660
Note:
Unless otherwise indicated, C
1
= C
2
= 10 µF, ESR
C1
= ESR
C2
= 1
,
T
A
= 25°C. See
Figure 1-1.
0
-1
5
4
3
V+ = +5V
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
-2
-3
-4
-5
-6
-7
-8
-9
-10
0
10
20 30 40 50 60 70 80 90 100
OUTPUT CURRENT (mA)
LV OPEN
2
1
0
-1
-2
-3
-4
-5
0
10
20 30 40 50 60
LOAD CURRENT (mA)
70
80
SLOPE 55Ω
FIGURE 2-7:
Current.
POWER CONVERSION EFFICIENCY (%)
100
90
80
70
60
50
40
30
20
10
0
1.5
Output Voltage vs. Output
FIGURE 2-10:
Current.
POWER CONVERSION EFFICIENCY (%)
100
90
80
70
60
50
40
30
20
10
0
10
Output Voltage vs. Load
20
V+ = 2V
18
100
90
SUPPLY CURRENT (mA)
14
12
10
8
6
4
2
3.0
4.5
6.0
7.5
LOAD CURRENT (mA)
0
9.0
70
60
50
40
30
20
V+ = +5V
10
0
60
20
30
40
50
LOAD CURRENT (mA)
FIGURE 2-8:
Supply Current and Power
Conversion Efficiency vs. Load Current.
2
V+ = +2V
FIGURE 2-11:
Supply Current and Power
Conversion Efficiency vs. Load Current.
OUTPUT VOLTAGE (V)
1
0
-1
SLOPE 150Ω
-2
0
1
2
3
4
5
6
LOAD CURRENT (mA)
7
8
FIGURE 2-9:
Current.
Output Voltage vs. Load
DS21465C-page 4
2002-2011 Microchip Technology Inc.
SUPPLY CURRENT (mA)
16
80
TC7660
3.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in
Table 3-1.
TABLE 3-1:
Pin No.
1
2
3
4
5
6
7
8
PIN FUNCTION TABLE
Symbol
NC
CAP
+
GND
CAP
LV
OSC
V
+
-
Description
No connection
Charge pump capacitor positive terminal
Ground terminal
Charge pump capacitor negative terminal
Output voltage
Low voltage pin. Connect to GND for V+ < 3.5V
Oscillator control input. Bypass with an external capacitor to slow the oscillator
Power supply positive voltage input
V
OUT
3.1
Charge Pump Capacitor (CAP
+
)
3.5
Low Voltage Pin (LV)
Positive connection for the charge pump capacitor, or
flying capacitor, used to transfer charge from the input
source to the output. In the voltage-inverting configura-
tion, the charge pump capacitor is charged to the input
voltage during the first half of the switching cycle. Dur-
ing the second half of the switching cycle, the charge
pump capacitor is inverted and charge is transferred to
the output capacitor and load.
It is recommended that a low ESR (equivalent series
resistance) capacitor be used. Additionally, larger
values will lower the output resistance.
The low voltage pin ensures proper operation of the
internal oscillator for input voltages below 3.5V. The low
voltage pin should be connected to ground (GND) for
input voltages below 3.5V. Otherwise, the low voltage
pin should be allowed to float.
3.6
Oscillator Control Input (OSC)
3.2
3.3
Ground (GND)
Charge Pump Capacitor (CAP
-
)
The oscillator control input can be utilized to slow down
or speed up the operation of the TC7660. Refer to
Section 5.4 “Changing the TC7660 Oscillator Fre-
quency”,
for details on altering the oscillator
frequency.
Input and output zero volt reference.
3.7
Power Supply (V
+
)
Negative connection for the charge pump capacitor, or
flying capacitor, used to transfer charge from the input
to the output. Proper orientation is imperative when
using a polarized capacitor.
Positive power supply input voltage connection. It is
recommended that a low ESR (equivalent series resis-
tance) capacitor be used to bypass the power supply
input to ground (GND).
3.4
Output Voltage (V
OUT
)
Negative connection for the charge pump output
capacitor. In the voltage-inverting configuration, the
charge pump output capacitor supplies the output load
during the first half of the switching cycle. During the
second half of the switching cycle, charge is restored to
the charge pump output capacitor.
It is recommended that a low ESR (equivalent series
resistance) capacitor be used. Additionally, larger
values will lower the output ripple.
2002-2011 Microchip Technology Inc.
DS21465C-page 5
