DocumentationDatasheet
Application Note
Reliability Data
LT Journal
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Features
- RF Power Amplifier Control in ThinSOT™ 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 VCC 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
Typical Application
Description
The LTC4400-1 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 temperature 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.
SOT-23,MS-8
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LTC4400-1ES6#PBF | SOT | 6 | E | $1.56 | |
| LTC4400-1ES6#TRMPBF | SOT | 6 | E | $1.61 | $1.27 |
| LTC4400-1ES6#TRPBF | SOT | 6 | E | $1.25 | |
| LTC4400-2EMS8#PBF | MSOP | 8 | E | $1.86 | $1.60 |
| LTC4400-2EMS8#TRPBF | MSOP | 8 | E | $1.66 | |
| LTC4400-1ES6 | SOT | 6 | E | $3.12 | |
| LTC4400-1ES6#TR | SOT | 6 | E | $2.50 | |
| LTC4400-2EMS8 | MSOP | 8 | E | $3.72 | $3.20 |
| LTC4400-2EMS8#TR | MSOP | 8 | E | $3.32 | |
| LTC4400-1ES6#TRM | SOT | 6 | E | $3.22 | $2.54 |
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.
| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC420A-A | LTC4400-1 | Power Output Controller for RF Power Amplifiers used in Cellular Phones | Contact Factory | |
| DC420A-B | LTC4401-1 | Power Output Controller for RF Power Amplifiers used in Cellular Phones | Contact Factory |