End of Life. Last Available Purchase Date is 31-Dec-2014
Si9145
Vishay Siliconix
Low-Voltage Switchmode Controller
FEATURES
2.7-V to 7-V Input Operating Range
Voltage-Mode PWM Control
High-Speed, Source-Sink Output Drive (200 mA)
Internal Oscillator (up to 2 MHz)
Standby Mode
0−100% Controllable Maximum Duty-Cycle
DESCRIPTION
The Si9145 switchmode controller IC is ideally suited for high
efficiency dc/dc converters in low input voltage systems.
Operation is guaranteed down to 2.7 V, with a minimum
start-up voltage of 3.0 V making the Si9145 ideal for use with
NiCd, NMH, and lithium ion battery packs. A mode select pin
allows the output driver polarity to be programmed allowing the
device to function as a step-up or step-down converter.
Features include a precision bandgap reference, a wide
bandwidth error amplifier, a 2-MHz oscillator, an input voltage
monitor with standby mode and a 200-mA output driver.
Supply current in normal operation is typically 1.1 mA and
250 A in standby mode.
The Si9145 implements conventional voltage mode control.
The maximum duty cycle in boost mode can be limited by
voltage on D
MAX
/SS pin. Frequency can be externally
programmed by selection of R
OSC
and C
OSC
.
The Si9145 is available in both standard and lead (Pb)-free
16-pin SOIC and TSSOP packages and is specified over the
industrial temperature range (−25 C to 85 C).
FUNCTIONAL BLOCK DIAGRAM
1.5-V Reference
Generator
V
DD
UVLO
SET
UVLO
V
REF
V
UVLO
ENABLE
Temp
Sense
S
OTS
R
MODE SELECT
D
MAX
/SS
COMP
Error Amp
NI
FB
+
−
+
−
Logic
Control
Driver
V
S
OUTPUT
P
GND
GND
+
−
C
OSC
R
OSC
Oscillator
Pentium
is a trademark of Intel Corporation. PowerPC
is a trademark of IBM.
www.vishay.com
Document Number: 70021
S-40710—Rev. K, 19-Apr-04
1
Si9145
Vishay Siliconix
ABSOLUTE MAXIMUM RATINGS
Voltages Referenced to GND.
V
DD
, V
S
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 V
P
GND
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
"0.3
V
V
DD
to V
S
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
−0.3
V
Linear Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
−0.3
V to V
DD
to +0.3 V
Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
−0.3
V to V
DD
to +0.3 V
Continuous Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 mA
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
−65
to 125_C
Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150_C
Power Dissipation (Package)
a
16-Pin SOIC (Y Suffix)
b
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 900 mW
16-Pin TSSOP (Q Suffix)
c
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 925 mW
Thermal Impedance (
Q
JA
)
16-Pin SOIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140_C/W
16-Pin TSSOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135_C/W
Notes
a. Device mounted with all leads soldered or welded to PC board.
b. Derate 7.2 mW/_C above 25_C.
c. Derate 7.4 mW/_C above 25_C.
RECOMMENDED OPERATING RANGE
Voltages Referenced to GND.
V
DD
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 V to 7 V
V
S
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 V to 7 V
f
OSC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 kHz to 2 MHz
R
OSC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 kW to 250 kW
C
OSC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 pF to 200 pF
Linear Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to V
DD
Digital Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to V
DD
V
REF
Load Resistance
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
>150 kW
SPECIFICATIONS
Test Conditions
Unless Otherwise Specified
a
Parameter
Reference
Output Voltage
V
REF
I
REF
=
−10
mA
T
A
= 25_C
1.455
1.477
1.50
1.545
1.523
V
Limits
B Suffix
−
25 to 85_C
Symbol
2.7 V
v
V
DD
v
7 V, V
DD
= V
S
GND = P
GND
Min
b
Typ
Max
b
Unit
Oscillator
Maximum Frequency
c
Accuracy
R
OSC
Voltage
Minimum Start-Up Voltage
50% D
MAX
/SS
100% D
MAX
/SS
D
MAX
/SS Input Current
Voltage Stability
c
g
y
Temperature Stability
c
f
MAX
f
OSC
V
ROSC
V
DDOSC
V
DMAX
50%
V
DMAX
100%
I
DMAX
MODE SELECT = V
DD
D
MAX
= 0 to V
DD
2.7 V
v
V
DD
v
7 V, Ref to 4.8 V
Df/f
2.7 V
v
V
DD
v
4.2 V, Ref to 3.5 V
3.8 V
v
V
DD
v
5.6 V, Ref to 4.7 V
Referenced to 25_C
T
A
= 25_C
−100
−16
−8
−7
"5
3.0
1.30
1.58
100
16
8
7
%
nA
V
CC
= 3.0 V, C
OSC
= 47 pF, R
OSC
= 5.0 kW
V
CC
= 3.0 V
C
OSC
= 100 pF, R
OSC
= 6.98 kW
T
A
= 25_C
2.0
0.85
1.0
1.0
V
1.15
MHz
www.vishay.com
2
Document Number: 70021
S-40710—Rev. K, 19-Apr-04
Si9145
Vishay Siliconix
SPECIFICATIONS
Test Conditions
Unless Otherwise Specified
a
Parameter
Symbol
2.7 V
v
V
DD
v
7 V, V
DD
= V
S
GND = P
GND
Limits
B Suffix
−
25 to 85_C
Min
b
Typ
Max
b
Unit
Error Amplifier (C
OSC
= GND, OSC DISABLED)
Input Bias Current
Open Loop Voltage Gain
Offset Voltage
Unity Gain Bandwidth
c
Output Current
Power Supply Rejection
c
I
FB
A
VOL
V
OS
BW
I
EA
P
SRR
Source (V
FB
= 1 V, NI = V
REF
)
Sink (V
FB
= 2 V, NI = V
REF
)
2.7 V < V
DD
< 7.0 V
0.4
V
NI
= V
REF
V
NI
= V
REF
, V
FB
= 1.0 V
−1.0
47
−15
55
0
10
−2.0
0.8
60
−1.0
15
1.0
mA
dB
mV
MHz
mA
dB
UVLO
SET
Voltage Monitor
Under Voltage Lockout
Hysterisis
UVLO Input Current
V
UVLOHL
V
UVLOLH
V
HYS
I
UVLO
UVLO
SET
High to Low
UVLO
SET
Low to High
V
UVLOLH
−
V
UVLOHL
V
UVLO
= 0 to V
DD
−100
0.85
1.0
1.2
200
100
1.15
V
mV
nA
Output
Output High Voltage
Output Low Voltage
Peak Output Current
Peak Output Current
V
OH
V
OL
I
SOURCE
I
SINK
V
DD
= 2.7 V, I
OUT
=
−10
mA
V
DD
= 2.7 V, I
OUT
= 10 mA
V
DD
= 2.7 V, V
OUT
= 0 V
V
DD
= 2.7 V, V
OUT
= 2.7 V
150
2.55
2.60
0.06
−180
200
0.15
−130
V
mA
Logic
ENABLE Delay to Output
ENABLE Logic Low
ENABLE Logic High
ENABLE Input Current
MODE SELECT Logic Low
MODE SELECT Logic High
MODE SELECT Input Current
td
EN
V
ENL
V
ENH
I
EN
V
MODEL
V
MODEH
I
MODE
MODE SELECT = 0 to V
DD
0.8 V
DD
−1.0
1.0
ENABLE = 0 to V
DD
0.8 V
DD
−1.0
1.0
0.2 V
DD
ENABLE Rising to OUTPUT
1.5
0.2 V
DD
ns
V
mA
V
mA
Over Temperature Sense
Trip Point
Output Low Voltage
Output High Voltage
T
TRIP
V
OTSL
V
OTSH
V
DD
= 2.7 V, I
OUT
= 1
mA
V
DD
= 2.7 V, I
OUT
=
−1
mA
2.55
150
0.06
2.6
0.15
_C
V
Supply
Supply Current
−
Normal Mode
Supply Current
−
Standby Mode
V
DD
= 2.7 V, f
OSC
= 1 MHz, R
OSC
= 6.98 kW
I
DD
V
DD
= 7 V, f
OSC
= 1 MHz, R
OSC
= 6.98 kW
ENABLE = Low
1.1
1.6
250
1.5
2.3
330
mA
mA
Notes
a. C
STRAY
< 5 pF on C
OSC
. After Start-Up, V
DD
of
w
3 V.
b. The algebraic convention whereby the most negative value is a minimum and the most positive a maximum, is used in this data sheet.
c. Guaranteed by design, not subject to production testing.
Document Number: 70021
S-40710—Rev. K, 19-Apr-04
www.vishay.com
3
Si9145
Vishay Siliconix
TYPICAL CHARACTERISTICS (25_C UNLESS NOTED)
1.515
1.510
1.505
V REF (V)
1.500
1.495
1.490
1.485
2
3
4
5
6
7
8
V
DD
−
Supply Voltage (V)
V REF (V)
V
REF
vs. Supply Voltage
V
REF
with 10
mA
Load
1.515
1.510
1.505
1.500
1.495
1.490
1.485
−25
V
REF
vs. Temperature
V
DD
= 3.6 V
0
25
50
75
100
125
t
−
Temperature (_C)
1.515
1.510
1.505
V
REF
vs. Load Current
80
60
Error Amplifier Gain and Phase
0
Gain
−30
Phase (deg)
Phase
−60
−90
−120
40
Gain (dB)
5.0 V
2.7, 3.0, 3.6 V
20
0
−20
V REF (V)
1.500
7.0 V
1.495
1.490
1.485
0
5
10
15
20
25
30
V
REF
−
Sourcing Current (mA)
−40
0.0001
0.001
0.01
0.1
1
10
100
f
−
Frequency (MHz)
−150
25
Supply Current
vs.Supply Voltage and Output Load
f = 1 MHz
25
Supply Current
vs. Switching Frequency and Output Load
V
DD
= 3.6 V
20
Supply Current (mA)
C
L
= 2,200 pF
20
Supply Current (mA)
C
L
= 2,200 pF
15
900 pF
10
100 pF
5
10 pF
0
2
3
4
5
6
7
15
900 pF
10
5
100 pF
10 pF
0
0.5
1.0
1.5
2.0
V
DD
−
Supply Voltage (V)
www.vishay.com
Switching Frequency (MHz)
Document Number: 70021
S-40710—Rev. K, 19-Apr-04
4
Si9145
Vishay Siliconix
TYPICAL CHARACTERISTICS (25_C UNLESS NOTED)
Supply Current
vs. Frequency and Supply Voltage
5
1.9
C
L
= 10 pF
V
DD
= 7.0 V
1.7
Normal Current (mA)
5.0 V
C
L
= 10 pF
f = 1 MHz
Supply Current
vs. Supply Voltage and Temperature
4
Supply Current (mA)
1.5
T
A
= 85_C
25_C
−25_C
3
1.3
2
3.6 V
2.7 V
1.1
3.0 V
1
0.0
0.2
0.4
0.6
0.8
1.0
0.9
2.5
3.5
4.5
5.5
6.5
7.5
f
−
Frequency (MHz)
V
DD
−
Supply Voltage (V)
Standby Current
vs. Supply Voltage and Temperature
270
100
Duty Cycle vs. D
MAX
/SS Voltage
260
Standby Current (m A)
T
A
= 85_C
80
250
Duty Cycle (%)
25_C
60
240
−25_C
230
40
20
220
2
3
4
5
6
7
V
DD
−
Supply Voltage (V)
1.20
1.15
Switching Frequency (MHz)
1.10
1.05
1.00
0.95
0.90
2
3
4
5
6
7
V
DD
−
Supply Voltage (V)
Document Number: 70021
S-40710—Rev. K, 19-Apr-04
0
1.0
1.1
1.2
1.3
D
MAX
/SS (V)
1.4
1.5
1.6
Switching Frequency vs. Supply Voltage
R
OSC
= 6.98 kW
C
OSC
= 100 pF
Switching Frequency (MHz)
10.00
Frequency vs. R
OSC
/C
OSC
1.00
4.99 kW
12.1 kW
24.9 kW
0.10
49.9 kW
100 kW
249 kW
0.01
40
100
C
OSC
−
Capacitance (pF)
www.vishay.com
200
300
5
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