Si9117
Vishay Siliconix
High-Frequency Converter for Telecom Applications
FEATURES
D
D
D
D
On-board high-voltage, 1-W Switching FET
Switching Frequencies of Up to 1 MHz
Synchronization Capability
Easily Compensated Current-Mode Operation
D
D
D
D
Operates with Input Voltages Up to 200 V
1.8-MHz Error Amplifier
Soft-Start
Latched SHUTDOWN
DESCRIPTION
The Si9117 high-efficiency converter for telecom systems
running off 48 V is ideal for emerging applications such as
interactive video (IV) set-top boxes and microcell base
stations, such as those used for Personal Communications
Systems (PCS). IV set-top boxes and microcell base stations
typically require less than 15 W of power and have access to
the analog telephone line power. Both IV set-top boxes and
microcell base stations process extremely low-level,
modulated analog signals (on the order of
mVs),
making the
frequency and energy content of radiated and conducted
noise a major issue. These application circuits are also
constrained in terms of available board space and place a
premium on minimal footprint.
Processing high-frequency, modulated analog signals for
video or RF requires receivers with sensitivities in the range of
0.5 to 25
mV.
At these levels, noise generated by switchmode
power conversion can impair the signal recovery process.
Controlling radiated noise is a matter of proper layout and
shielding. Controlling conducted noise is a matter of limiting its
energy and isolating the conducted energy’s fundamental and
harmonic frequencies to bands which will not affect the
frequencies of interest. The high-frequency, synchronized
switching of the Si9117 enables this design requirement. First,
for a given output current, high-frequency switching attenuates
output ripple, minimizing conducted energy.
Second,
synchronizing the high switching frequency to an external
frequency allows the fundamental and its harmonics to be
moved out of range of the frequency bands of interest. An
additional benefit of high-frequency switching is reduced size
and cost of the inductor and the output filter capacitance.
In addition to these mandatory design considerations, the
Si9117 is easy to design with and compensate, and takes a
minimum of board area to implement: an important benefit in
high-volume/small-package applications such as set-top
boxes and microcell base stations.
The Si9117 is available in both standard and lead (Pb)-free
packages.
The combination of an on-board, high-voltage, 1-W switch and
a PWM IC with operational input voltage of 200 V allows
operation off of the analog telephone line, even with the worst
case battery voltage and ringing voltage. Once the converter
has started up, a simple bootstrap circuit can provide power to
the IC by raising the source voltage of the n-channel, depletion
mode, start-up FET above its gate voltage of 9.2 V. This
technique lowers system costs, reduces the area required for
circuit implementation, and minimizes circuit power
consumption.
APPLICATIONS CIRCUIT
V
IN
+
V
OUT
1
2
3
SYNC
4
5
6
7
8
16
15
14
13
12
11
10
9
NC
SHUTDOWN
Si9117
Document Number: 70027
S-40750—Rev. E, 19-Apr-04
www.vishay.com
1
Si9117
Vishay Siliconix
ABSOLUTE MAXIMUM RATINGS
Voltages Referenced to
−V
IN
V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 V
+V
IN
(Note: V
CC
< +V
IN
+ 0.3 V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 V
Logic Input (SHUTDOWN, SYNC) . . . . . . . . . . . . . . . .
−0.3
V to V
CC
+ 0.3 V
Linear Inputs (FEEDBACK, SENSE,
SOFT-START) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
−0.3
V to V
CC
+ 0.3 V
HV Pre-Regulator Input Current (continuous) . . . . . . . . . . . . . . . . . . . . . 5 mA
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
−65
to 150_C
Operating Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
−40
to 85_C
Junction Temperature (T
J
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150_C
Drain-Source Voltage (T
A
= 25_) (V
DS
)
a
. . . . . . . . . . . . . . . . . . . . . . . . . 200 V
Continuous Drain Current (T
A
= 25_) (I
D
)
a
. . . . . . . . . . . . . . . . . . . . . . . 1.0 A
Power Dissipation (Package)
a
16-Pin SOIC (Y Suffix)
b
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 900 mW
Thermal Impedance (Q
JA
)
16-Pin SOIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140_C/W
Notes
a. Device mounted with all leads soldered or welded to PC board, t
v
2
sec.
b. Derate 7.2 mW/_C above 25_C.
RECOMMENDED OPERATING RANGE
Voltages Referenced to
−V
IN
V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.5 V to 16.5 V
+V
IN
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 V to 200 V
f
OSC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 kHz to 2 MHz
R
OSC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 kW to 1 MW
C
OSC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 pF to 200 pF
Linear Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to V
CC
−
4 V
Digital Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to V
CC
SPECIFICATIONS
Test Conditions Unless Specified
Parameter
Reference
OSC Disabled, T
A
= 25_C
Output Voltage
Short Circuit Current
Load Regulation
V
R
I
SREF
DV
R
/DI
R
OSC Disabled
Over Voltage and Temperature Ranges
c
V
REF
=
−V
IN
I
REF
= 0 to
−1
mA
3.94
3.88
4.0
4.0
−30
10
4.06
4.12
−5
40
V
mA
mV
Limits
Min
a
Typ
b
Max
a
Unit
Symbol
Oscillator Disabled
−V
IN
= 0 V, V
CC
= 10 V
Oscillator
Initial Accuracy
Voltage Stability
c
Temperature Coefficient
c
Sync Output Current (Master Mode)
Sync Output Current (Slave Mode)
f
OSCd
Df/f
OSC TC
I
SYNC(M)
I
SYNC(S)
R
OSC
= 374 kW , C
OSC
= 200 pF
R
OSC
= 70 kW , C
OSC
= 200 pF
R
OSC
= 70 kW , C
OSC
= 200 pF
Df/f
= [f(16.5 V)
−
f(9.5 V)] / f(9.5 V)
−40
v
T
A
v
85_C, f
OSC
= 100 kHz
V
ROSC
v
5 V
V
ROSC
= V
CC
"1.0
90
450
100
500
1
200
"3.0
"1
"500
110
550
2
500
kHz
%
ppm/_C
mA
nA
Error Amplifier (C
OSC
=
−V
IN
OSC Disabled)
Input BIAS Current
Input OFFSET Voltage
Open Loop Voltage Gain
c
Unity Gain Bandwidth
c
Output Current
Power Supply Rejection
I
FB
V
OS2
A
VOL
BW
I
OUT
PSRR
Source (V
FB
= 3.5 V, NI = V
REF
)
Sink (V
FB
= 4.5 V, NI = V
REF
)
9.5 V
v
V
CC
v
16.5 V
1.0
50
65
1.8
V
FB
= 5 V, NI = V
REF
<1.0
"5
80
2.7
−2.7
2.4
80
−1.0
"200
"25
nA
mV
dB
MHz
mA
dB
www.vishay.com
2
Document Number: 70027
S-40750—Rev. E, 19-Apr-04
Si9117
Vishay Siliconix
SPECIFICATIONS
Test Conditions Unless Specified
Parameter
Pre-Regulator/Start-Up
Input Leakage Current
Pre-Regulator Start-Up Current
V
CC
Pre-Regulator Voltage
V
PR
−V
UVLO
(Turn-On)
Undervoltage Lockout Hysteresis
+I
IN
I
START
V
PR
V
DELTA
V
HYST
+V
IN
= 200 V, V
CC
w
10 V
+V
IN
= 48 V, t
PW
v
300
ms,
V
CC
= V
UVLO
+V
IN
= 48 V
8
8.8
0.1
0.18
t1
20
9.1
0.25
0.28
9.4
0.7
0.4
V
10
mA
mA
Limits
Min
a
Typ
b
Max
a
Unit
Symbol
Oscillator Disabled
−V
IN
= 0 V, V
CC
= 10 V
Supply
Supply Current
I
CC
C
LOAD
v
50 pF
f
OSC
= 100 kHz
f
OSC
= 500 kHz
1.8
3.7
2.5
4.5
mA
Protection
Current Limit Threshold Voltage
Current Limit Delay to Output
c
SHUTDOWN Logic Threshold
SHUTDOWN Delay to Latched Output
c
SHUTDOWN Pull-Up Current
Soft-Start Current
Output Inhibit Voltage
V
SENSE
t
d
V
SD
t
SD
I
SD
I
SS
V
SS(off)
Soft-Start Voltage to Disable Driver Output
See Figure 2
V
SD
= 0 V
12
12
V
FB
= 0 V, NI = V
REF
V
SENSE
= 1.5 V, See Figure 1
1.035
1.16
105
2.8
0.21
22
22
1.6
1.30
130
0.5
1.0
30
30
0.5
V
ns
V
ms
mA
V
Switch
Zero-Gate Voltage Drain Current
Drain-Source On-State Resistance
e
I
DSS
r
DS(on)
V
DS
= 200 V, V
GS
= 0 V, T
A
= 25_C
V
GS
= 10 V, I
D
= 1.0 A, T
A
= 25_C
0.7
0.8
5
1
mA
W
Notes
a. The algebraic convention whereby the most negative value is a minimum and the most positive a maximum.
b. Typical values are for DESIGN AID ONLY, not guaranteed nor subject to production testing.
c. Guaranteed by design, not subject to production test.
d. C
STRAY
v
5 pF on C
OSC
.
e. Pulse Test; Pulse Width
v
300
ms,
Duty Cycle
v
2%.
TIMING WAVEFORMS
1.5 V−
CURRENT
SENSE
50%
0
t
d
V
CC
t
r
= 10 ns
SHUTDOWN
50%
t
SD
V
CC
t
f
= 10 ns
DRAIN
0
10%
DRAIN
0
10%
V
CC
Document Number: 70027
S-40750—Rev. E, 19-Apr-04
www.vishay.com
3
Si9117
Vishay Siliconix
TYPICAL CHARACTERISTICS
Output Frequency
1000
C
OSC
= 47 pF
100 pF
f OUT
−
Output Frequency (kHz)
150 pF
I CC
−
Supply Current (mA)
200 pF
12
16
Supply Current vs. Output Frequency
V
CC
= 12 V
100
8
4
10
10
100
R
OSC
−
Oscillator Resistance (k)
1000
0
0
200
400
600
800
1000
f
OUT
−
Output Frequency (kHz)
7
Supply Current vs. Supply Voltage
1.25
Output Frequency vs. Supply Voltage
R
OSC
= 60 kW
C
OSC
= 47 pF
f
OUT
= 250 kHz
I CC
−
Supply Current (mA)
6
f OUT
−
Output Frequency (MHz)
9
10
11
12
13
14
15
16
17
1.00
0.75
5
0.50
4
0.25
3
V
CC
−
Supply Voltage (V)
0.00
8
10
12
V
CC
−
Supply Voltage (V)
14
16
1.2
r DS(on) Drain-Source On-Resistance (
W
)
−
Drain-Source On Resistance vs. Temperature
26
I
SS
(Soft-Start) vs. Temperature
1.0
I SS
−
Soft Start Current (
m
A)
−25
0
25
50
75
100
24
22
0.8
20
0.6
18
0.4
−50
16
−50
−25
0
25
50
75
100
T
J
−
Temperature (_C)
www.vishay.com
T
J
−
Temperature (_C)
Document Number: 70027
S-40750—Rev. E, 19-Apr-04
4
Si9117
Vishay Siliconix
TYPICAL CHARACTERISTICS
Error Amp Gain and Phase
−20
−40
−60
Phase (
_
)
−80
Phase
−100
−120
100
80
60
Gain (dB)
40
20
0
−20
0.1
4020
4010
4000
3990
3980
3970
3960
−50
Reference Voltage vs. Temperature
Gain
1
10
100
1000
−140
4000
V REF
−
Reference Voltage (mV)
−25
0
25
50
75
100
f
−
Frequency (kHz)
215
f OSC
−
Oscillator Frequency (200 kHz)
Oscillator Frequency vs. Temperature
1050
f OSC
−
Oscillator Frequency (1 MHz)
210
f = 1 MHz
1025
205
1000
f = 200 kHz
200
975
195
−50
−25
0
25
50
75
950
100
T
J
−
Temperature (_C)
Document Number: 70027
S-40750—Rev. E, 19-Apr-04
www.vishay.com
5
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