CAT661EVA-GT3 ON Semiconductor, CAT661EVA-GT3 Datasheet - Page 9

• 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

Capacitor Selection
losses, especially at high load currents. The exact values of
C1 and C2 are not critical but low ESR capacitors are
necessary.
pronounced effect on the output. C1 currents are
approximately twice the output current and losses occur on
both the charge and discharge cycle. The ESR effects are
thus multiplied by four. A 0.5 Ω ESR for C1 will have the
same effect as a 2 Ω increase in CAT661 output impedance.
BOOST/FC
Table 5. VRIPPLE vs. FOSC
Low ESR capacitors are necessary to minimize voltage
The ESR of capacitor C1, the pump capacitor, can have a
(1)
(6)
LV
VRIPPLE (mV)
45
25
Figure 22. Oscillator
7.0 I
7.0 I
V
+
I
I
IOUT (mA)
~18 pF
100
100
OSC
(7)
http://onsemi.com
C1
FOSC (kHz)
+
135
NC
25
9
the load current. C2 is charged and discharged at a current
roughly equal to the load current. The internal switching
frequency is one−half the oscillator frequency.
(12.5 kHz switching frequency), a 150 mF C2 capacitor with
an ESR of 0.2 Ω and a 100 mA load peak−to−peak ripple
voltage is 45 mV.
1
2
3
4
Output voltage ripple is determined by the value of C2 and
For example, with a 25 kHz oscillator frequency
VRIPPLE + IOUT (FOSC
BOOST/FC
CAP+
GND
CAP−
REQUIRED FOR TTL LOGIC
Figure 23. External Clocking
CAT661
OSC
OUT
V+
LV
C2 (mF)
150
150
8
7
6
5
+
100 k
C2) ) IOUT
C2
−V
+
C2 ESR (W)
0.2
0.2
V
ESRC2
+
INPUT
OSC