TK717xxS
TEST CIRCUIT
VIN
IIN
VOUT
CL = 0.22
µF
GND
IOUT
A
VIN
CIN = 0.22
µF
V
A
VCONT
V
ICONT
CN = 0.001
µF
On/Off CONT
Noise Bypass (VREF)
TYPICAL PERFORMANCE CHARACTERISTICS
Noise Performance
TK71730S NOISE vs. CN
300
250
♠
CL = CERAMIC
♦
♦
CL
CL
CL
CL
CL
= 0.2
µF
= 0.4
µF
= 1.0
µF
= 2.2
µF
= 10
µF
NOISE vs VOUT
70
70
NOISE (µVrms)
IOUT = 30 mA
CN = 0.01µF
CL = 1.0
µF
(TANTALUM)
NOISE vs. IOUT
65
60
♦
♠
CN = 0.01
µF
CL
CL
CL
CL
CL
= 0.22
µF
= 0.47
µF
= 1.0
µF
= 2.2
µF
= 10
µF
NOISE (µVrms)
NOISE (µVrms)
200
150
100
50
0
0
CL = TANTALUM
♠
60
50
40
30
20
10
55
50
45
40
♦
35
30
0
25
♠
CL = TANTALUM
IOUT = 30 mA
BPF = 400 Hz ~ 80 kHz
BPF = 400 Hz ~ 80 kHz
10
100 1000 10000 100000
CN (pF)
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
VOUT (V)
50 75 100 125 150 175 200
IOUT (mA)
NOISE vs. IOUT
70
65
60
NOISE (µVrms)
NOISE vs. FREQUENCY
10
TK71730S
CIN = 10
µF
CL = 0.22
µF
(CERAMIC)
IOUT = 10 mA
CN = 0.01
µF
♦
♠
CL
CL
CL
CL
CL
= 0.22
µF
= 0.47
µF
= 1.0
µF
= 2.2
µF
= 10
µF
45
40
35
30
0
25
♦
♠
CL = CERAMIC
µ
V/
50
Hz
55
1
CN = 0.01
µF
0.1
CN = 0.10
µF
For better noise reduction it is
more effective to increase C
N
without increasing CL.
The recommended C
N
capaci-
tance is 6800 pF or 0.01
mF.
As the output voltage increases,
the noise will also increase.
0.01
50 75 100 125 150 175 200
IOUT (mA)
0.01
0.1
1
10
FREQUENCY (kHz)
100
October 2001 TOKO, Inc.
Page 5
TOKO [ TOKO, INC ]
