LTC1550L/LTC1551L
Low Noise, Switched
Capacitor Regulated
Voltage Inverters
FEATURES
s
s
s
s
s
s
s
s
DESCRIPTIO
s
s
Regulated Negative Voltage from a Single
Positive Supply
Low Output Ripple: Less Than 1mV
P-P
Typ
High Charge Pump Frequency: 900kHz
Small Charge Pump Capacitors: 0.1µF
Requires Only Four External Capacitors
Fixed – 4.1V, –2.5V, –2V or Adjustable Output
Shutdown Mode Drops Supply Current to <1µA
High Output Current: Up to 20mA (Depending on
V
CC
to V
OUT
Range)
Output Regulation: 2.5% Over Line, Load and
Temperature
Available in 8-Lead MSOP, 8-Lead Narrow SO and
16-Lead Narrow SSOP
The LTC
®
1550L/LTC1551L are switched capacitor charge
pump voltage inverters which include internal linear post-
regulators to minimize output ripple. The LTC1550L fixed
output voltage versions include –4.1V, –2.5V and –2V with
ripple voltages typically below 1mV
P-P
. The LTC1550L is
also available in an adjustable output voltage version. The
LTC1550L/LTC1551L are ideal for use as bias voltage
generators for GaAs transmitter FETs in portable RF and
cellular telephone applications.
The LTC1550L/LTC1551L operate from single 2.7V to
5.5V supplies and draw typical quiescent currents of
3.5mA with a 5V supply. Each device includes a TTL
compatible Shutdown pin which drops supply current to
0.2µA typically. The LTC1550L Shutdown pin is active low
(SHDN), while the LTC1551L Shutdown pin is active high
(SHDN). Only four external components are required: an
input bypass capacitor, two 0.1µF charge pump capacitors
and a filter capacitor at the linear regulator output. The
adjustable LTC1550L/LTC1551L require two additional re-
sistors to set the output voltage. The LTC1550L/LTC1551L
will supply up to 20mA (depending on V
CC
to V
OUT
range),
while maintaining guaranteed output regulation of
±2.5%.
Both fixed voltage and adjustable LTC1550L/LTC1551L
are available in 8-lead MSOP and SO plastic packages: the
adjustable LTC1550L is also available in a 16-pin SSOP
with the REG pin.
V
OUT
Output Noise and Ripple
APPLICATIO S
s
s
s
s
GaAs FET Bias Generators
Negative Supply Generators
Battery-Powered Systems
Single Supply Applications
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
3.6V
1
2
SHDN
V
CC
+
REG
CP
OUT
8
7
R1
10k
POWER VALID
+
2.2µF
C
IN
LTC1550L-2
3
4
C1
GND
C1
–
6
5
C
CP
0.1µF
V
OUT
AC COUPLED
2mV/DIV
V
OUT
C1
0.1µF
C
OUT
10µF
V
OUT
= –2V
I
LOAD
= 5mA
C
L
0.1µF
1550L/51L TA01
Figure 1. – 2V Generator with 1mV
P-P
Noise
U
5µs/DIV
1550L/51L TA01a
U
+
U
1
LTC1550L/LTC1551L
ABSOLUTE
MAXIMUM
RATINGS
Supply Voltage ...................................................... 5.5V
Output Voltage ............................. 0.3V to (V
CC
– 10.5V)
Total Voltage, V
CC
to CP
OUT ..........................................
10.8V
Input Voltage (SHDN Pin) ........... – 0.3V to (V
CC
+ 0.3V)
Input Voltage (REG Pin) ............................. – 0.3V to 6V
Output Short-Circuit Duration .............................. 30 sec
PACKAGE/ORDER INFORMATION
TOP VIEW
SHDN*
V
CC
C1
+
V
OUT
1
2
3
4
8
7
6
5
REG (ADJ*)
CP
OUT
GND
C1
–
SHDN* 1
V
CC
2
C1
+
3
V
OUT
4
MS8 PACKAGE
8-LEAD PLASTIC MSOP
*SHDN FOR LTC1550L, SHDN FOR LTC1551L
*FOR ADJUSTABLE VERSION
T
JMAX
= 150°C,
θ
JA
= 200°C/W
ORDER PART NUMBER
LTC1550LCMS8
LTC1550LCMS8-2
LTC1550LCMS8-2.5
LTC1550LCMS8-4.1
LTC1551LCMS8
LTC1551LCMS8-4.1
*SHDN FOR LTC1550L, SHDN FOR LTC1551L
*FOR ADJUSTABLE VERSION
T
JMAX
= 150°C,
θ
JA
= 135°C/W
MS8 PART MARKING
LTEG
LTGR
LTFV
LTEH
LTFQ
LTFT
Consult factory for Military grade parts and additional voltage options.
ELECTRICAL CHARACTERISTICS
The
q
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
CC
= 2.7V to 5.25V, C1 = C
CP
= 0.1µF, C
OUT
= 10µF, T
A
= 25°C unless otherwise specified. (Note 3)
PARAMETER
Supply Voltage
(Adjustable, Fixed –2V)
(Fixed –2.5V)
(Fixed – 4.1V)
V
REF
Reference Voltage
∆V
REF
Reference Voltage
∆(V
CC
– V
OUT)
Line Regulation
I
S
Supply Current
SYMBOL
V
CC
CONDITIONS
q
q
q
V
CC
= 5V, ADJ = GND, V
REF
= –V
OUT
I
OUT
= 0mA, 2.7V
≤
V
CC
≤
5.25V
V
CC
= 5V, V
SHDN
= V
CC
(LTC1550L) or GND (LTC1551L)
q
V
CC
= 5V, V
SHDN
= GND (LTC1550L) or V
CC
(LTC1551L)
q
2
U
U
W
W W
U
W
(Note 1)
Commercial Temperature Range ................. 0°C to 70°C
Extended Commercial Operating
Temperature Range (Note 3) .............. – 40°C to 85°C
Industrial Temperature Range ................ – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
TOP VIEW
8
7
6
5
REG (ADJ*)
CP
OUT
GND
C1
–
NC 1
C1
+
2
TOP VIEW
16 V
CC
15 SHDN
14 REG
13 NC
12 ADJ
11 CP
OUT
10 NC
9
NC
NC 3
V
OUT
4
C1
–
5
S8 PACKAGE
8-LEAD PLASTIC SO
PGND 6
AGND 7
NC 8
GN PACKAGE
16-LEAD PLASTIC SSOP
T
JMAX
= 150°C,
θ
JA
= 150°C/W
ORDER PART NUMBER
LTC1550LCS8
LTC1550LCS8-2
LTC1550LCS8-2.5
LTC1550LCS8-4.1
LTC1551LCS8
LTC1551LCS8-4.1
ORDER PART NUMBER
LTC1550LCGN
LTC1550LIGN
GN PART MARKING
1550L
1550LI
MIN
2.7
3.05
4.5
TYP
MAX
5.25
5.25
5.25
UNITS
V
V
V
V
mV/V
mA
µA
1.225
2.5
3.65
0.2
7
10
LTC1550L/LTC1551L
ELECTRICAL CHARACTERISTICS
The
q
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
CC
= 2.7V to 5.25V, C1 = C
CP
= 0.1µF, C
OUT
= 10µF, T
A
= 25°C unless otherwise specified. (Note 3)
SYMBOL
f
OSC
V
OL
I
REG
V
IH
V
IL
I
IN
t
ON
PARAMETER
Internal Oscillator Frequency
REG Output Low Voltage
REG Sink Current
SHDN Input High Voltage
SHDN Input Low Voltage
SHDN Input Current
Turn-On Time
CONDITIONS
I
REG
= 1mA, V
CC
= 5V
V
REG
= 0.8V, V
CC
= 5V
V
CC
= 5V
V
CC
= 5V
V
SHDN
= V
CC
(All LTC1550L Versions)
V
SHDN
= V
CC
(All LTC1551L Versions)
V
CC
= 5V, I
OUT
= 10mA, –1.5V
≤
V
OUT
≤
4.1V
(LTC1550L/LTC1551L)
V
CC
= 5V, I
OUT
= 5mA, V
OUT
= – 4.5V
(LTC1550L/LTC1551L)
V
CC
= 5V, I
OUT
= 10mA, V
OUT
= – 2V
(LTC1550L-2)
V
CC
= 5V, I
OUT
= 10mA, V
OUT
= – 2.5V
(LTC1550L-2.5)
V
CC
= 5V, I
OUT
= 10mA, V
OUT
= – 4.1V
(LTC1550L-4.1/LTC1551L-4.1)
2.7V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
5mA
2.8V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
10mA
3.5V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
20mA
2.7V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
5mA
3.1V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
10mA
3.75V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
20mA
3.05V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
5mA
3.45V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
10mA
4.1V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
20mA
3.45V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
5mA
3.85V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
10mA
4.5V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
20mA
3.9V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
5mA
4.2V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
10mA
4.85V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
20mA
4.5V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
5mA
4.75V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
10mA
4.8V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
5mA
5.1V
≤
V
CC
≤
5.25V, 0
≤
I
OUT
≤
10mA
V
OUT
= 0V, V
CC
= 5.25V
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
MIN
TYP
900
0.1
10
MAX
0.8
UNITS
kHz
V
mA
V
V
µA
µA
ms
ms
ms
ms
ms
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
mA
mV
4
2
0.1
5
1
1
1
1
1
– 1.537
– 1.537
– 1.537
– 2.05
– 2.05
– 2.05
– 2.562
– 2.562
– 2.562
– 3.075
– 3.075
– 3.075
– 3.587
– 3.587
– 3.587
– 4.203
– 4.203
– 4.613
– 4.613
– 1.5
– 1.5
– 1.5
– 2.0
– 2.0
– 2.0
– 2.5
– 2.5
– 2.5
– 3.0
– 3.0
– 3.0
– 3.5
– 3.5
– 3.5
– 4.1
– 4.1
– 4.5
– 4.5
80
1
0.8
1
20
5
5
5
5
5
– 1.463
– 1.463
– 1.463
– 1.95
– 1.95
– 1.95
– 2.438
– 2.438
– 2.438
– 2.925
– 2.925
– 2.925
– 3.413
– 3.413
– 3.413
– 3.998
– 3.998
– 4.388
– 4.388
200
V
OUT
Output Regulation
(LTC1550L/LTC1551L)
Output Regulation
(LTC1550L/LTC1550L-2/
LTC1551L)
Output Regulation
(LTC1550L/LTC1550L-2.5/
LTC1551L)
Output Regulation
(LTC1550L/LTC1551L)
Output Regulation
(LTC1550L/LTC1551L)
Output Regulation
(LTC1550L/LTC1550L-4.1)
(LTC1551L/LTC1551L-4.1)
Output Regulation
(LTC1550L/LTC1551L))
Output Short-Circuit Current
Output Ripple Voltage
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
I
SC
V
RIPPLE
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground unless otherwise
specified. All typicals are given at T
A
= 25°C.
Note 3:
The LTC1550LC/LTC1551LC are guaranteed to meet specified
performance from 0°C to 70°C and are designed, characterized and
expected to meet these extended temperature limits, but are not tested at
– 40°C and 85°C. The LTC1550LI is guaranteed to meet the extended
temperature limits.
3
LTC1550L/LTC1551L
TYPICAL PERFORMANCE CHARACTERISTICS
Oscillator Frequency vs
Temperature
975
4.5
SUPPLY CURRENT (mA)
POSITIVE SUPPLY VOLTAGE (V)
OSCILLATOR FREQUENCY (kHz)
925
875
825
775
725
V
CC
= 5V
V
OUT
= –4.1V
675
–55 –35 –15
5 25 45 65 85 105 125
TEMPERATURE (˚C)
1550L/51L G01
Maximum Output Current
vs Supply Voltage
80
MAXIMUM OUTPUT CURRENT (mA)
70
60
50
40
30
20
10
0
2.25
T
A
= 25°C
2.0
REFERENCE VOLTAGE (V)
START-UP TIME (ms)
V
OUT
= –2V
V
OUT
= –2.5V
V
OUT
= –4.1V
2.75
3.25 3.75 4.25
SUPPLY VOLTAGE (V)
Startup Time (LTC1550L Shown)
5V
SHDN
0V
0V
V
OUT
– 4.1V
POWER VALID
5V
0V
0.2ms/DIV
1550/51 G07
4
U W
4.75
Supply Current vs Temperature
5.0
V
CC
= 5V
V
OUT
= – 4.1V
6.0
5.6
5.2
4.8
4.4
4.0
3.6
3.2
2.8
2.4
Minimum Required V
CC
vs V
OUT
and I
OUT
I
OUT
= 20mA
4.0
3.5
3.0
I
OUT
= 5mA
I
OUT
= 10mA
2.5
–55 –35 –15
5 25 45 65 85 105 125
TEMPERATURE (°C)
1550L/51L G02
2.0
–5
–4
–2
–1
–3
OUTPUT VOLTAGE (V)
0
1550L/51L G03
Start-Up Time vs Supply Voltage
2.5
T
A
= 25°C
1.24
1.238
1.236
1.234
1.232
1.230
1.228
1.226
1.224
1.222
1.220
5.25
0
2.25
1.218
2.75
3.25 3.75 4.25
SUPPLY VOLTAGE (V)
4.75
5.25
Reference Voltage vs V
CC
+ |V
OUT
|
T
A
= 25°C
1.5
V
OUT
= –4.1V
R
L
= 820Ω
V
OUT
= –2V
R
L
= 390Ω
1.0
0.5
4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
V
CC
+ |V
OUT
| (V)
1550L/51L G06
1550L/51L G04
1550L/51L G05
Load Transient Response
(See Figure 3, V
CC
= 5V)
Line Transient Response
(See Figure 3, I
L
= 10mA)
V
OUT
5mV/DIV
AC
COUPLED
10mA
I
OUT
0mA
1ms/DIV
1550/51 G08
V
OUT
5mV/DIV
AC
COUPLED
5.25V
4.75V
V
CC
2ms/DIV
1550/51 G09
LTC1550L/LTC1551L
TYPICAL PERFORMANCE CHARACTERISTICS
Output Spectrum (*See Figure 1)
90
80
70
60
10
NOISE (µV/√Hz)
NOISE (dBµV)
NOISE (dBµV)
50
40
30
20
10
0
–10
100k
1M
FREQUENCY (Hz)
10M
1550L/51L G10
Spot Noise (See Figure 3)
10
90
80
70
NOISE (µV/√Hz)
50
40
30
20
10
0
0.1
V
CC
= 5V
I
L
= 5mA
C
IN
= 2.2µF
C
OUT
= 4.7µF
C
L
= 0.1µF
1
10
FREQUENCY (kHz)
100
1550L/51L G13
NOISE (µV/√Hz)
NOISE (dBµV)
1
0.01
* On first page of data sheet.
U W
Spot Noise (*See Figure 1)
90
80
70
Output Spectrum (See Figure 3)
V
CC
= 5V
I
L
= 5mA
C
IN
= 2.2µF
C
OUT
= 4.7µF
C
L
= 0.1µF
1
60
50
40
30
20
10
0
0.1
0.01
1
10
FREQUENCY (kHz)
100
1550 /51L G11
–10
100k
1M
FREQUENCY (Hz)
10M
1550L/51L G12
Output Spectrum (See Figure 3)
10
V
CC
= 5V
I
L
= 5mA
C
IN
2.2µF
C
OUT
= 10µF
C
L
= 0.1µF
Spot Noise (See Figure 3)
V
CC
= 5V
I
L
= 5mA
C
IN
= 2.2µF
C
OUT
= 10µF
C
L
= 0.1µF
60
1
0.1
–10
100k
1M
FREQUENCY (Hz)
10M
1550L/51L G14
0.01
1
10
FREQUENCY (kHz)
100
1550L/51L G15
5
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