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FA7611CP(E)
1
s
Description
The FA7611CP(E) is a bipolar IC containing basic circuit
necessary for PWM-type switching power supply control.
s
Features
Low-voltage operation (V
CC
= 3.6 to 22V)
Predrivers: Totem-pole output or open-collector for CH1 and
open-collector output for CH2
Latch-mode short-circuit protection function (no malfunction
due to electrical noise)
soft-start function
Undervoltage lock-out function
One capacitor shared for short circuit protection and for soft start
to minimize the number of external discrete components
s
Applications
Battery power supply for portable equipment
s
Dimensions, mm
SSOP-16
1
8
9
16
0.6
0~10
0.65
7.9
0.3
5.3
6.2
0.1
0.1
0.2
+0.1
0.05
0.3
2.1max
DIP-16
Bipolar IC
For Switching Power Supply Control
s
Block diagram
FA7611CP(E)
Pin
Pin
Description
No.
symbol
1
CT
Oscillator timing capacitor
2
CS
Capacitor for soft-start, short-
circuit protection and delay
3
DT2
Dead time adjustment
4
IN2 (+)
Non-inverting input to error
amplifier
5
IN2 ()
Inverting input to error amplifier
6
FB2
Error amplifier output
7
GND
Ground
8
OUT2
CH. 2 Output
9
VCC
Power supply
10
OUT1R
CH. 1 Current limiting resistor
11
OUT1
CH. 1 Output
12
FB1
Error amplifier output
13
IN1 ()
Inverting input to error amplifier
14
IN1 (+)
Non-inverting input to error
amplifier
Reference voltage (0.5V)
15
DT1
Dead time adjustment
16
REF
Reference voltage output (2.5V)
1
16
9
8
19.4
6.5
7.6
3.4
4.3max
1.5
0.81
3.1min
0.2min
0~15
0~15
0.5
0.1
2.54
0.25
0.3
+0.1
0.05
FA7611CP(E)
2
s
Electrical characteristics (Ta = 25
C, V
CC
= 6V, R
T
= 33k
, C
T
= 1000pF)
Reference voltage section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Output voltage
V
REF
I
OR
= 1mA
2.425
2.475
2.525
V
Line regulation
L
INE
V
CC
= 3.6 to 20V,
I
OR
=1mA
4
12
mV
Load regulation
L
OAD
I
OR
= 0.1 to 1mA
1
6
mV
Output voltage variation due to temperature change
V
TC1
Ta = 20 to +25
C
1
1
%
V
TC2
Ta = +25 to +85
C
1
1
%
Oscillator section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Oscillation frequency
f
OSC
C
T
= 1000pF,
R
T
= 33k
95
115
135
kHz
Frequency variation 1 (due to supply voltage change)
f
dV
V
CC
= 3.6 to 20V
1
%
Frequency variation 2 (due to temperature change)
f
dT
Ta = 20 to +85
C
5
%
Error amplifier section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Reference voltage
V
B
0.484
0.494
0.504
V
Input bias current
I
B
5
100
nA
Open-loop voltage gain
A
V
70
dB
Unity-gain bandwidth
G
B
0.6
MHz
Maximum output voltage (Pin 6 and Pin 12)
V
OM+
R
NF
= 100k
V
REF
0.2
V
V
OM
R
NF
= 100k
200
mV
Output source current (Pin 6 and Pin 12)
I
OM+
V
OM
= 1V
40
85
200
A
PWM comparator section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Input threshold voltage (Pin 6 and Pin 12)
V
TH0
Duty cycle = 0%
0.85
0.95
V
Input threshold voltage (Pin 6 and Pin 12)
V
TH50
Duty cycle = 50%
1.1
V
s
Absolute maximum ratings
Item
Symbol
Rating
Unit
Supply voltage
V
CC
22
V
Reference voltage output current
I
OR
5
mA
Output current
I
O
50
mA
Total power dissipation
P
d
400
mW
Operating temperature
T
opr
20 to +85
C
Storage temperature
T
stg
40 to +150
C
s
Recommended operating conditions
Item
Symbol
Min.
Max.
Unit
Supply voltage
V
CC
3.6
20
V
Feedback resistance
R
NF
100
k
Oscillator timing capacitor
C
T
220
22,000
pF
Oscillator timing resistance
R
T
10
100
k
Oscillation frequency
f
OSC
5
200
kHz
FA7611CP(E)
3
Dead time adjustment circuit section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Input bias current (Pin 3 and Pin 15)
I
BDT
80
300
nA
Input threshold voltage (Pin 3 and Pin 15)
V
TH DT0
Duty cycle = 0%
0.22
0.32
V
Input threshold voltage (Pin 3 and Pin 15)
V
TH DT50
Duty cycle = 50%
0.46
V
Short-circuit protection circuit section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Input threshold voltage (Pin 6 and Pin 12)
V
TH PC
1.20
1.50
1.80
V
Charge current (Pin 2)
I
CHG
Pin 2 = 0V, Pin 6, Pin 12 = 2V
10
30
50
A
Latch-mode threshold voltage (Pin 2)
V
TH LA
1.20
1.50
1.80
V
Undervoltage lockout circuit section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
OFF-to-ON threshold voltage
V
TH ON
2.65
V
ON-to-OFF threshold voltage
V
TH OFF
2.60
V
Voltage hysteresis
V
HYS
50
mV
Output section
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
CH. 1 H-level output voltage (Pin 11)
V
01H
R
L
= 10k
3.5
4.0
V
CH. 1 L-level output voltage (Pin 11)
V
01L
Output sink current = 20mA
0.25
0.65
V
CH. 1 Output source current (Pin11)
I
SOURCE1
R
OUT1
= 470
8
11
mA
(Pin 11) = 0V
CH. 2 L-level output voltage (Pin 8)
V
02L
Output sink current = 20mA
1.0
1.5
V
Overall device
Item
Symbol
Test condition
Min.
Typ.
Max.
Unit
Supply current
I
CC LA
Latch mode
2.0
3.0
mA
Operating-state supply current
I
CC AV
R
L
=
Duty cycle = 50%
3.5
6.0
mA
FA7611CP(E)
4
s
Characteristic curves (Ta = 25
C)
Oscillation frequency (f
OSC
) vs.
Output duty cycle vs. CS terminal voltage (V
CS
)
timing capacitor capacitance (C
T
)
Output duty cycle vs. DT terminal voltage (V
DT
)
Output duty cycle vs. FB terminal voltage (V
FB
)
CH-1 output source current (I
SOURCE1
) vs.
L-level output voltage (V
O1L
) vs.
supply voltage (V
CC
)
CH. 1 output sink current (I
SINK1
)
FA7611CP(E)
5
L-level output voltage (V
O2L
)
Supply current (I
CC
) vs. supply voltage(V
CC
)
vs. CH. 2 output sink current (I
SINK2
)
Operating-state supply current (I
CCAV
) vs.
oscillation frequency (f
OSC
)
Error amplifie frequency (f) vs. valtage gain (A
V
) / phase (
)
Phase
[deg]
FA7611CP(E)
6
s
Application circuit
Flyback-transformer type and chopper type buck converter circuit
Chopper type buck converter and inverting converter circuit
Parts tolerances characteristics are not defined in the circuit design
sample shown above.
When designing an actual circuit for a product, you must determine
parts tolerances and characteristics for safe and economical
operation.
Please connect a capacitor, which the value is about 0.01
F to 0.1
F,
between VCC
and REF terminals in order to prevent from irregular
output pulse at start-up.
3.3k
30.1k
1k
0.01
VCC
22000p
16
REF
DT1
IN1(+)
IN1()
FB1
FA7611CP(E)
OUT1
OUT1R
VCC
CT
CS
DT2
IN2(+)
IN2()
FB2
GND
OUT2
1
15
2
14
3
13
4
12
5
11
6
10
7
9
8
Q
1
L
1
R
11
Buck
5V
VCC
Inverting
5V
+
C
1
+
C
10
D
10
+
+
5.02k
100k
22k
4.7
330k
1000p
2.2k
820k
56k
1k
47000p
C
2
+
C
20
D
20
R
20
R
21
Q
2
L
2
R
out1
3.3k
63.5k
1k
100k
VCC
22000p
22k
0.01
1M
VCC
16
15
14
13
12
11
10
9
+
TR
REF DT1 IN1(+) IN1() FB1
FA7611CP(E)
OUT1 OUT1R VCC
CT
CS
DT2 IN2(+)IN2() FB2
GND OUT2
1
2
3
4
5
6
7
8
C
1
Q
1
+
Flyback
24V
10V
10V
Buck
5V
C
11
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