CAT661EVA-GT3 ON Semiconductor, CAT661EVA-GT3 Datasheet - Page 8

• Manufacturer Part Number: CAT661EVA-GT3
• Description: Charge Pumps CHG PUMP VOLT CONVERTER
• Manufacturer: ON Semiconductor

Specifications of CAT661EVA-GT3

• Rohs: yes
• Function: Inverting
• Output Voltage: 5 V to 11 V
• Output Current: 100 mA
• Supply Current: 0.5 mA
• Maximum Operating Temperature: + 105 C
• Package / Case: SOIC-8
• Input Voltage: 2.5 V to 5.5 V
• Maximum Power Dissipation: 500 mW
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Switching Frequency: 12.5 KHz

Oscillator Frequency Control
from an external source. Figure 22 shows a functional
diagram of the oscillator circuit.
nominal oscillator frequency is 25 kHz. The pump
frequency is one−half the oscillator frequency.
Table 4.
Open
BOOST/FC = V+
Open or
BOOST/FC = V+
Open
Pin Connection
The switching frequency can be raised, lowered or driven
The CAT661 oscillator has four control modes:
If BOOST/FC and OSC are left floating (Open), the
BOOST/FC
BOOST/FC
External Capacitor
External Clock
OSC
Connection
(1)
(7)
8x
OSC Pin
Open
Open
OSC
(6)
LV
external clock
Figure 21. CAT661 Block Diagram
Frequency of
Frequency
Oscillator
Nominal
135 kHz
25 kHz
B2
(8)
V
−
+
CLOSED WHEN
http://onsemi.com
V
+
f
f
> 3.0 V
8
discharge currents are increased, and the frequency is
increased by approximately 6 times. Increasing the
frequency will decrease the output impedance and ripple
currents. This can be an advantage at high load currents.
Increasing the frequency raises quiescent current but allows
smaller capacitance values for C1 and C2.
frequency is lowered. By using the BOOST/FC pin and an
external capacitor at OSC, the operating frequency can be
set.
one−half that of the oscillator.
can be easily achieved by driving Pin 7 and leaving the
BOOST pin open, as shown in Figure 22. The output current
from Pin 7 is small, typically 1 mA to 8 mA, so a CMOS can
drive the OSC pin. For 5 V applications, a TTL logic gate can
be used if an external 100 k
shown in Figure 23.
By connecting the BOOST/FC pin to V+, the charge and
If pin 7, OSC, is loaded with an external capacitor the
Note that the frequency appearing at CAP+ or CAP− is
Driving the CAT661 from an external frequency source
SW1
CAP
CAP
GND
+
(2)
(4)
(3)
+
−
C1
SW2
Ω
(N) = Pin Number
pull−up resistor is used as
VOUT
(5)
+
C2