LTC4400-1/LTC4400-2
RF Power Controllers with
450kHz Loop BW and
45dB Dynamic Range
FEATURES
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DESCRIPTIO
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RF Power Amplifier Control in ThinSOT
TM
Package
Internal Schottky Diode Detector with > 45dB Range
Wide Input Frequency Range:
300MHz to 2.7GHz (LTC4400-1)
300MHz to 2GHz (LTC4400-2)
Autozero Loop Cancels Offset Errors and
Temperature Dependent Offsets
Wide V
CC
Range: 2.7V to 6V
Automatic Bandwidth Control Improves Low Power
Ramp Response
Allows Direct Connection to Battery
RF Output Power Set by External DAC
Internal Frequency Compensation
Rail-to-Rail Power Control Output
Power Control Signal Overvoltage Protection
Low Operating Current: 1mA
Low Shutdown Current: 10µA
Two Pole PCTL Input Filtering
Low Profile (1mm) ThinSOT (LTC4400-1) and
8-Pin MSOP (LTC4400-2) Packages
The LTC
®
4400-1 is a SOT-23 RF power controller for fast
turn-on RF power amplifiers operating in the 300MHz to
2.7GHz range. Examples include the Hitachi PF08109B,
PF08122B, PF08123B, PF08107B and RF Micro Devices
RF3108. For slow turn-on RF power amplifiers refer to the
LTC4401-1/LTC4401-2.
RF power is controlled by driving the RF amplifier power
control pin and sensing the resultant RF output power via
a directional coupler or capacitive tap. The RF input
voltage is peak detected using an on-chip Schottky diode.
This detected voltage is compared to the DAC voltage at
the PCTL pin to control the output power. The RF power
amplifier is protected against high power control pin
voltages.
Internal and external offsets are cancelled over tempera-
ture by an autozero control loop, allowing accurate low
power programming. The shutdown feature disables the
part and reduces the supply current to <10µA.
A dual control channel version (LTC4400-2) is also
available in an 8-pin MSOP package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
APPLICATIO S
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GSM/GPRS Cellular Telephones
PCS Devices
Wireless Data Modems
U.S. TDMA Cellular Phones
TYPICAL APPLICATIO
LTC4400-1 Detector Characteristics at
900MHz and 1800MHz
10000
T
A
= 25°C
V
CC
= 3.6V
PCTL REFERENCED DETECTOR
OUTPUT VOLTAGE (mV)
LTC4400-1 Dual Band Cellular Telephone Transmitter
50Ω
Li-Ion
0.1µF
6
1
BAND
SELECT
900MHz
OUTPUT
V
CC
LTC4400-1
RF
0.4pF
SHDN
4
SHDN
V
PCA
5
V
PC
900MHz
INPUT
1.8GHz
INPUT
3
DAC
PCTL
GND
2
PA MODULE
1.8GHz
OUTPUT
1
–26 –22 –18 –14 –10 –6 –2 2 6 10 14 18
RF INPUT POWER (dBm)
4400 TA01
4400 TA04
U
1000
900MHz
100
1800MHz
10
U
U
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1
LTC4400-1/LTC4400-2
ABSOLUTE
AXI U
RATI GS
V
CC
to GND .............................................. – 0.3V to 6.5V
V
PCA/B
Voltage to GND ............................ – 0.3V to 3.2V
PCTL Voltage to GND ................. – 0.3V to (V
CC
+ 0.3V)
RF Voltage to GND ............................ (V
CC
– 2.6V) to 7V
BSEL, SHDN Voltage to GND ...... – 0.3V to (V
CC
+ 0.3V)
PACKAGE/ORDER I FOR ATIO
TOP VIEW
RF 1
GND 2
PCTL 3
6 V
CC
5 VPCA
4 SHDN
ORDER PART
NUMBER
LTC4400-1ES6
S6 PART MARKING
LTWZ
V
CC
V
PCA
V
PCB
GND
1
2
3
4
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
T
JMAX
= 125°C,
θ
JA
= 230°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
PARAMETER
V
CC
Operating Voltage
I
VCC
Shutdown Current
I
VCC
Operating Current
V
PCA/B
V
OL
V
PCA/B
Dropout Voltage
V
PCA/B
Voltage Clamp
V
PCA/B
Output Current
V
PCA/B
Enable Time
V
PCA/B
Bandwidth
V
PCA/B
Load Capacitance
V
PCA/B
Slew Rate
V
PCA/B
Droop
V
PCA/B
Start Voltage
BSEL, SHDN Input Threshold
BSEL, SHDN Input Current
PCTL Input Voltage Range
PCTL Input Resistance
PCTL Input Filter
Autozero Range
(Note 4)
Open Loop (Note 9)
V
CC
= 2.7V to 6V
BSEL = SHDN = 3.6V
(Note 7)
SHDN = 0V
SHDN = HI, I
VPCA/B
= 0mA
R
LOAD
= 400Ω, Enabled
I
LOAD
= 6mA, V
CC
= 2.7V
PCTL = 1V
V
PCA/B
= 2.4V, V
CC
= 3V
SHDN = V
CC
(Note 5)
CONDITIONS
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 3.6V, SHDN = HI, unless otherwise noted.
MIN
q
q
q
q
q
q
q
q
C
LOAD
= 100pF, R
LOAD
= 400Ω (Note 8)
V
PCTL
= 2V Step, C
LOAD
= 100pF,
R
LOAD
= 400Ω (Note 3)
2
U
U
W
W W
U
W
(Note 1)
I
VPCA/B
.................................................................. 10mA
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Maximum Junction Temperature ........................ 125°C
Lead Temperature (Soldering, 10 sec)................ 300°C
TOP VIEW
8
7
6
5
RF
BSEL
SHDN
PCTL
ORDER PART
NUMBER
LTC4400-2EMS8
MS8 PART MARKING
LTXB
MS8 PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 250°C/W
TYP
10
1.2
MAX
6
20
1.9
0.05
V
CC
– 0.25
UNITS
V
µA
mA
V
V
V
mA
µs
kHz
kHz
pF
V/µs
µV/ms
2.7
0
2.7
7
350
2.9
10
9
450
230
2.5
1
3.1
10.2
560
100
PCTL < 80mV
PCTL > 160mV
q
q
q
1.8
3
q
q
q
q
q
270
0.35
16
0
60
450
24
90
270
550
1.4
36
2.4
120
400
mV
V
µA
V
kΩ
kHz
mV
q
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LTC4400-1/LTC4400-2
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 3.6V, SHDN = HI, unless otherwise noted.
PARAMETER
RF Input Frequency Range
RF Input Power Range
(LTC4400-1)
CONDITIONS
LTC4400-1(Note 6)
LTC4400-2(Note 6)
RF Frequency = 900MHz (Note 6)
RF Frequency = 1800MHz (Note 6)
RF Frequency = 2400MHz (Note 6)
RF Frequency = 2700MHz (Note 6)
RF Frequency = 900MHz (Note 6)
RF Frequency = 2000MHz (Note 6)
Referenced to V
CC
q
ELECTRICAL CHARACTERISTICS
MIN
300
300
–28
–26
–24
–22
–28
–26
150
TYP
MAX
2700
2000
18
18
16
16
18
18
UNITS
MHz
MHz
dBm
dBm
dBm
dBm
dBm
dBm
Ω
RF Input Power Range
(LTC4400-2)
RF Input Resistance
250
350
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
Specifications over the – 40°C to 85°C operating temperature range
are assured by design, characterization and correlation with statistical
process controls.
Note 3:
Slew rate is measured open loop. The slew time at V
PCA/B
is
measured between 1V and 2V.
Note 4:
Maximum DAC zero-scale offset voltage that can be applied to PCTL.
Note 5:
This is the time from SHDN rising edge 50% switch point to
V
PCA
= 0.25V.
Note 6:
Guaranteed by design. This parameter is not production tested.
Note 7:
Includes maximum DAC offset voltage and maximum control
voltage.
Note 8:
Bandwidth is calculated using the 10% to 90% rise time:
BW = 0.35/rise time
Note 9:
Measured 12µs after SHDN = HI.
TYPICAL PERFOR A CE CHARACTERISTICS
PCTL REFERENCED DETECTOR OUTPUT VOLTAGE (mV)
PCTL REFERENCED DETECTOR OUTPUT VOLTAGE (mV)
PCTL REFERENCED DETECTOR OUTPUT VOLTAGE (mV)
LTC4400-1 Detector Characteristics
at 900MHz
10000
75°C
25°C
–30°C
1000
100
10
1
–28
–22 –16 –10 –4
2
8
RF INPUT POWER (dBm)
U W
14
LTC4400-1 Detector Characteristics
at 1800MHz
10000
75°C
25°C
–30°C
LTC4400-1 Detector Characteristics
at 2400MHz
10000
75°C
25°C
–30°C
1000
1000
100
100
10
10
1
–26 –20
–14 –8
–2
4
10
RF INPUT POWER (dBm)
16
4401 G02
1
–24 –20 –16 –12 –8 –4 0 4 8
RF INPUT POWER (dBm)
12 16
4401 G03
4401 G01
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LTC4400-1/LTC4400-2
TYPICAL PERFOR A CE CHARACTERISTICS
PCTL REFERENCED DETECTOR OUTPUT VOLTAGE (mV)
PCTL REFERENCED DETECTOR OUTPUT VOLTAGE (mV)
10000
PCTL REFERENCED DETECTOR OUTPUT VOLTAGE (mV)
LTC4400-1 Detector Characteristics
at 2700MHz
75°C
25°C
–30°C
1000
100
10
1
–22 –18 –14 –10 –6 –2 2 6
RF INPUT POWER (dBm)
PI FU CTIO S
(LTC4400-1/LTC4400-2)
RF (Pins 1/8):
RF Feedback Voltage. This input is referenced
to V
CC
. The frequency range is 300MHz to 2700MHz for the
LTC4400-1 and 300MHz to 2000MHz for the LTC4400-2.
This pin has an internal 250Ω termination, an internal
Schottky diode detector and peak detector capacitor.
GND (Pins 2/4):
System Ground.
PCTL (Pins 3/5):
Analog Input. The external power control
DAC drives this input. The amplifier servos the RF power
until the RF detected signal equals the DAC signal. The
input impedance is typically 90kΩ.
V
PCB
(Pin 3): (LTC4400-2 Only)
Power Control Voltage
Output. This pin drives an external RF power amplifier
power control pin. The maximum load capacitance is
100pF.
4
U W
10 14
LTC4400-2 Detector Characteristics
at 900MHz
10000
75°C
25°C
–30°C
LTC4400-2 Detector Characteristics
at 1800MHz
10000
75°C
25°C
–30°C
1000
1000
100
100
10
10
1
–28
–22 –16 –10 –4
2
8
RF INPUT POWER (dBm)
14
4400 G05
1
–26 –20
–14 –8
–2
4
10
RF INPUT POWER (dBm)
16
4400 G06
4401 G04
U
U
U
SHDN (Pins 4/6):
Shutdown Input. A logic low on the SHDN
pin places the part in shutdown mode. A logic high places
the part in enable mode. SHDN has an internal 150k pull-
down resistor to ensure that the part is in shutdown when
the drivers are in a three-state condition.
V
PCA
(Pins 5/2):
Power Control Voltage Output. This pin
drives an external RF power amplifier power control pin.
The maximum load capacitance is 100pF.
V
CC
(Pins 6/1):
Input Supply Voltage, 2.7V to 6V. V
CC
should be bypassed with 0.1µF and 100pF ceramic capaci-
tors. Used as return for RF 250Ω termination.
BSEL (Pin 7): (LTC4400-2 Only)
Selects V
PCA
when Low
and V
PCB
when High. This input has an internal 150k
resistor to ground.
sn4400 4400fas
LTC4400-1/LTC4400-2
BLOCK DIAGRA
68Ω
33pF
V
CC
6
250Ω
RF
1
28pF
30k
60µA
GND
2
60µA
VBG
PCTL
SHDN
NOTE: THE DIRECTIONAL COUPLER SHOWN IN THIS FIGURE MAY BE REPLACED
WITH A COUPLING CAPACITOR AND RESISTOR AS DESCRIBED IN APPLICATION
NOTE 91 “LOW COST COUPLING METHODS FOR RF POWER DETECTORS REPLACE
DIRECTIONAL COUPLERS”
W
V
REF
(LTC4400-1)
RF IN
Li-Ion
RF PA
50Ω
TXENB
AUTOZERO
–
AZ
+
+
GAIN
COMPRESSION
–
GM
+
+
–
30k
80mV
270kHz
FILTER
CLAMP
+
C
C
BUFFER
5
+
RF DET
38k
–
30k
30k
V
PCA
–
22k
51k
V
REF
+
–
33.4k
TXENB
10µs
DELAY
6k
12Ω
CONTROL
100Ω
150k
4
3
LTC4400-1
4400-1 BD
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