TC682EOA Microchip Technology, TC682EOA Datasheet - Page 4

• Manufacturer Part Number: TC682EOA
• Description: IC INVERTING VOLT DOUBLER 8SOIC
• Manufacturer: Microchip Technology
• Type: Switched Capacitor (Charge Pump), Doubler, Invertingr

Specifications of TC682EOA

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: -4.8 ~ -11 V
• Current - Output: 10mA
• Frequency - Switching: 12kHz
• Voltage - Input: 2.4 ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Power - Output: 470mW
• Primary Input Voltage: 5.5V
• No. Of Outputs: 1
• Output Current: 10mA
• No. Of Pins: 8
• Operating Temperature Range: -40°C To +85°C
• Peak Reflow Compatible (260 C): Yes
• Switching Frequency Max: 12kHz
• Function: Inverting
• Output Voltage: - 10 V
• Maximum Operating Temperature: 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

TC682
3.0
FIGURE 3-1:
3.1
V
cycle, capacitor C
then switched to ground and the charge in C
transferred to C
potential across capacitor C
FIGURE 3-2:
3.2
V
ative terminal of C
capacitor C
transferring the generated -10V to C
the positive side of capacitor C
the negative side is connected to ground. C
switched to V
DS21453C-page 4
GND
SS
SS
(+5V)
V
IN
transfer – phase two of the clock connects the neg-
charge storage – before this phase of the clock
–
+
C
C
DETAILED DESCRIPTION
Phase 1
Phase 2
1
2
SW2
SW1
+
–
+
–
3
C
1
and the positive terminal of C
CC
-5V
7
1
2
3
All Caps = 3.3 μF
2
and GND and Phase 1 begins again.
C
C
C
C
–
1
1
1
2
2
. Since C
+
–
+
–
2
TC682
+
–
is already charged to +5V. C
GND
V
to the negative side of reservoir
IN
SW4
5
TC682 Test Circuit
Charge Pump – Phase 1
6
SW3
V
C
OUT
2
2
2
4
+
is now -10V.
V
1
is at +5V, the voltage
IN
is switched to +5V and
–
+
= +5V
C
OUT
+
3
–
. Simultaneously,
C
3
V
2
OUT
R
to ground,
L
2
is then
V –
1
1
OUT
–
+
is
is
FIGURE 3-3:
3.3
The TC682 has on-chip Zener diodes that clamp V
to approximately 5.8V, and V
exceed the maximum supply voltage or excessive
current will be shunted by these diodes, potentially
damaging the chip. The TC682 will operate over the
entire operating temperature range with an input
voltage of 2V to 5.5V.
3.4
Theoretically a charge pump voltage multiplier can
approach
conditions:
• The charge pump switches have virtually no offset
• Minimal power is consumed by the drive circuitry.
• The impedances of the reservoir and pump
For the TC682, efficiency is as shown below:
Voltage Efficiency = V
Power Loss
There will be a substantial voltage difference between
V
tors C
output loads.
Larger values of reservoir capacitor C
output ripple. Larger values of both pump and reservoir
capacitors improve the efficiency. See Section 4.2
“Capacitor Selection” “Capacitor Selection”.
OUT
and are extremely low on resistance.
capacitors are negligible.
and -2V
1
and C
+
–
Maximum Operating Limits
Efficiency Considerations
SW2
SW1
100%
C
2
1
IN
are high with respect to their respective
if the impedances of the pump capaci-
SW4
= I
efficiency
+
–
V
V
OUT
OUT
OUT
DROP
SW3
Charge Pump – Phase 2
© 2006 Microchip Technology Inc.
C
-10V
(V
2
= -2V
/ (-2V
= (I
DROP
+5V
OUT
OUT
IN
IN
under
)
)
+ V
) (R
+
–
to -11.6V. Never
DROP
C
OUT
3
the
3
)
V
will reduce
OUT
following
IN