HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Features DC POWER MANAGEMENT - SMT 13 13 - 1 • Single Positive Voltage Supply (5V to 16.5V) • Short Circuit Protection (Power Foldback) • Adjustable Drain Voltage 3V to 15V • Adjustable Over/Under-Current Alarm • Adjustable Drain Current up to 500mA • Adjustable Low Vdd Voltage Alarm • Internal Negative Voltage Generator • Automated Power-up Sequencing • Active Bias Current Regulation • Enable Input for Active Bias Control • Stable Bias Current Over Temperature and Process Variation and Aging • Trigger-out Output for Daisy Chain Power-Up and Power-Down Sequencing Typical Applications • Cellular Base Station • Military & Space • Wireless Infrastructure Equipment • Test Instrumentation • Microwave Radio & VSAT Functional Diagram For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER General Description HMC920LP5E is an active bias controller which generates a regulated Drain voltage and actively adjusts the gate voltage of an external amplifier to achieve constant bias current. It can be used to bias any enhancement and depletion type amplifiers operating in Class-A regime with Drain voltages (VDRAIN) from 3V to 15V and drain currents (IDRAIN) up to 500mA, offering a complete biasing solution. HMC920LP5E achieves excellent bias stability over supply, temperature and process variations, and eliminates the required calibration procedures used to prevent RF performance degradation due to such variations. The HMC920LP5E is housed in an RoHS compliant 5x5 mm QFN leadless package with an exposed backside pad to improve thermal characteristics. Electrical Specifications, TA = +25°C, Vdd = Vdd1 = Vdd2 = 15V Supply Voltage Symbol Conditions Vdd Typ. 5 EN = Vdig Vdd = 5V Quiescent Current Min. IDD Vdd = 15V Max. 16.5 35 Units V mA EN = GND 20 mA EN = Vdig 35 mA EN = GND 20 mA Negative Voltage Output VNEG -2.5 V Oscillator Frequency FOSC 250 kHz Bandgap Reference VBGC 2 V VDIG Feedback VDIGFB 2.5 V LDOCC Feedback LDOFB Enable Input Threshold ENTHRS ALMTRIG Input Threshold ALMTRIG Low Vdd Alarm Threshold VddCHK 2 Vinlow Vinhigh 1.4 V V Vinlow Vinhigh V 1 1 1.4 V V 3.8 V VDRAIN Characteristics DRAIN Current Adjustment Range DRAIN Current Change Over Supply Voltage DRAIN Current Change Over Temperature DRAIN Adjustment Range VDRAIN Change Over Supply Voltage VDRAIN Change Over Temperature IDRAIN ΔIDRAINV 0 VDRAIN ΔVDRAIN 500 0.05 VDRAIN set to 6V, IDRAIN set to 100mA, 0.03 3 VDRAIN set to 6V, IDRAIN set to 100mA, mA %/V %/C 15 V 0.05 %/V 0.008 %/C VNEG Characteristics Negative Voltage Output VNEG VNEG Current Sink INEG 0 -2.5 60 mA V IG -4 4 mA 13 DC POWER MANAGEMENT - SMT Parameter VGATE Characteristics GATE Current Supply VGATE Low Level VG_MIN VNEG V VGATE High Level VG_MAX VNEG+4.5 V VDIG Characteristics Adjustment Range VDIG VDIG Current Source IDIG 3.5 5 V 30 mA For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com 13 - 2 HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER IDRAIN Regulation Accuracy vs. Vdd [1][2] VDRAIN Line Regulation Over IDRAIN 110 +25C +85C -40C 108 CURRENT (mA) DRAIN VOLTAGE VDRAIN (V) 6.2 106 104 102 100 7 8 9 10 12 13 14 5.9 5.8 5.7 15 6.5 7.5 8.5 9.5 VDIG Line Regulation Over Temperature 3.5 No load condition No load condition DIGITAL VOLTAGE VDIG (V) DRAIN VOLTAGE VDRAIN (V) 6.1 6.06 6.02 5.98 +25C +85C -40C 5.94 5.9 6.5 7.5 8.5 9.5 3.48 3.46 3.44 +25C +85C -40C 3.42 3.4 10.5 11.5 12.5 13.5 14.5 15.5 16.5 5 6 7 8 9 10 11 12 13 14 15 16 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) VNEG Line Regulation Over Temperature VDRAIN Load Regulation Over Vdd 6.2 DRAIN VOLTAGE VDRAIN (V) -2.4 NEGATIVE VOLTAGE VNEG (V) 10.5 11.5 12.5 13.5 14.5 15.5 16.5 SUPPLY VOLTAGE (V) VDRAIN Line Regulation Over Temperature No load condition -2.42 -2.44 -2.46 +25C +85C -40C -2.48 -2.5 5 6 7 8 9 10 11 12 13 14 15 16 SUPPLY VOLTAGE (V) [1] IDRAIN is set to 110mA 13 - 3 6 SUPPLY VOLTAGE (V) 13 DC POWER MANAGEMENT - SMT 11 Idrain=0mA Idrain=100mA Idrain=200mA 6.1 6.1 6 5.9 Vdd=+7.5V Vdd=+10.0V Vdd=+16.5V 5.8 5.7 0 20 40 60 80 100 120 140 160 180 200 220 DRAIN LOAD CURRENT (mA) [2] HMC594LC3B is used as external amplifier For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER VDRAIN Load Regulation Over Temperature [1] VDIG Load Regulation Over Temperature 3.5 +25C +85C -40C 6.1 6 5.9 5.8 5.7 0 40 80 120 160 200 240 280 320 360 3.48 3.46 3.44 3.4 400 +25C +85C -40C 3.42 0 5 10 VNEG Load Regulation Over Temperature [2] 25 30 35 13 -2.3 NEGATIVE VOLTAGE VNEG (V) NEGATIVE VOLTAGE VNEG (V) 20 VNEG Load Regulation Over Temperature [3] -2.3 -2.4 -2.5 +25C +85C -40C -2.6 -2.7 15 DIGITAL LOAD CURRENT (mA) DRAIN LOAD CURRENT (mA) 0 5 10 15 20 -2.4 -2.5 -2.7 25 +25C +85C -40C -2.6 NEGATIVE SINK CURRENT (mA) 0 15 30 45 60 75 NEGATIVE SINK CURRENT (mA) Enable Waveform Disable Waveform A A 0V 0V B B C C DC POWER MANAGEMENT - SMT DIGITAL VOLTAGE VDIG (V) DRAIN VOLTAGE VDRAIN (V) 6.2 0V 0V 0V 0V 200 µs/div A Enable Pin, 5 V/div B VDRAIN, 2 V/div [1] Vdd = 7.5V C [2] Vdd = 5V 200 µs/div VGATE, 1 V/div A Enable Pin, 5 V/div B VDRAIN, 2 V/div C VGATE, 1 V/div [3] Vdd - 16.5V For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com 13 - 4 HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER VDRAIN Load Transient 6V A 6V A 0mA B 0mA B 20 us/div 13 DC POWER MANAGEMENT - SMT VDOCC Load Transient 20 us/div A VDRAIN, 500 mV/div A LDOCC, 200 mV/div B IDRAIN, 100 mA/div B IDRAIN, 100 mA/div VDIG Load Transient VNEG Load Transient 3.5V A 0mA B -2.5V A 0mA B 500 us/div 1 ms/div A VDIG, 50 mV/div A VNEG, 50 mV/div B IDIG, 20 mA/div B INEG, 5 mA/div Power Up Waveform Power Down Waveform A A B B 0V 0V 0V 0V C D C 0V 0V D 5 ms/div 13 - 5 10 ms/div A Vdd, 5V/div C VGATE, 1V/div A Vdd, 5V/div C VGATE, 1V/div B VDRAIN, 5V/div D VNEG, 1V/div B VDRAIN, 5V/div D VNEG, 1V/div For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Absolute Maximum Ratings [1] -0.3V to +16.5V CPGND to GND -0.3V to +0.3V VDIG to GND -0.3V to +5.5V Vdd1 to Vdd2 -0.3V to +0.3V VDIGFB, PORCAP, BGCAP, EN, CURALM, ALMTRIG to GND -0.3V to (VDIG + 0.3V) ALMSET, ALMC1, ALMC2, REF to GND -0.3V to (Vdd + 0.3V) VNEGFB, VGATE, VDRAIN, ISENSE to GND -0.3V to (Vdd + 0.3V) VNEGIN to GND -4V to (Vdd + 0.3V) ALML, ALMM, ALMH, LDOCC, LDOFB to GND -0.3V to (Vdd + 0.3V) Vdd1, Vdd2 to GND VGATEFB, TRGOUT, VddALM, VddCHK to GND Junction Temperature 125 °C Continuous Pdiss (T = 85 °C) (Derate 256.67 mW/°C above 85 °C) 10.27 Watts Thermal Resistance (RTH) (Junction to package bottom) 3.9 °C/W Storage Temperature -65 to +150 °C Operating Temperature -40 to +85 °C ESD Sensitivity (HBM) Class 1C Note that there are two different voltage domains on HMC920LP5E; a high voltage domain Vdd, and a low voltage domain VDIG. Take necessary precautions not to violate ABS MAX ratings of each subdomains. -0.3V to (VDIG + 0.3V) Outline Drawing NOTES: 1. LEADFRAME MATERIAL: COPPER ALLOY 2. DIMENSIONS ARE IN INCHES [MILLIMETERS] 3. LEAD SPACING TOLERANCE IS NON-CUMULATIVE. 4. PAD BURR LENGTH SHALL BE 0.15mm MAXIMUM. PAD BURR HEIGHT SHALL BE 0.05mm MAXIMUM. 5. PACKAGE WARP SHALL NOT EXCEED 0.05mm. 6. ALL GROUND LEADS AND GROUND PADDLE MUST BE SOLDERED TO PCB RF GROUND. 7. REFER TO HITTITE APPLICATION NOTE FOR SUGGESTED LAND PATTERN. Package Information Part Number Package Body Material Lead Finish HMC920LP5E RoHS-compliant Low Stress Injection Molded Plastic 100% matte Sn MSL Rating MSL1 [2] 13 DC POWER MANAGEMENT - SMT ELECTROSTATIC SENSITIVE DEVICE OBSERVE HANDLING PRECAUTIONS Package Marking [1] H920 XXXX [1] 4-Digit lot number XXXX [2] Max peak reflow temperature of 260 °C For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com 13 - 6 HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Pin Descriptions DC POWER MANAGEMENT - SMT 13 13 - 7 Pin Number Function Description 1, 2 Vdd1 Bias supply Pins. Connect supply voltage to all these pins with appropriate filtering. Vdd1 supply voltage should be same as Vdd2. 3 VDIG 3.5V LDO output for internal use. Output capability <30mA. Is not recommended for external use. 4 VDIGFB Feedback node for VDIG LDO. Should be left floating for regular operation. 5 PORCAP External capacitor for power-on-reset signal. 47pF to GND is needed. If longer POR duration is needed, can be increased. 10 ALMSET A resistor to ground is needed. The value of the resistor determines the alarm delay duration. The value of the resistor can be chosen between 10K and 10M. 12 FIXBIAS A high precision (e.g. 0.5%, ±25 ppm TCR) 10K resistor to ground is needed. Variance in the resistance will cause deviation in the bias current. 6 BGCAP External capacitor of bandgap output. Connect a 0.1uF or greater low ESR ceramic capacitor to GND. 7 EN Enable pin. System is enabled when Ven is HIGH (3.5V). IF left floating, Ven defaults to HIGH (enabled). 9 ALMTRG Dummy alarm trigger signal to create test alarm when taken HIGH (3.5V). Defaults to LOW (GND) when left floating. 8 CURALM Over/under current alarm (Generates an active HIGH signal). 24 TRGOUT Trigger out signal. Generates a HIGH (3.5V) signal when the active bias system stabilizes. This signal can be used to trigger next device (ENABLE) if more than one HMC920LP5E is used in a daisy chain. 31 VddALM Generates an active LOW signal if Vdd1 drops below 3.5V. Interface Schematic For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Pin Descriptions (Continued) Function Description 13 VREF 1.5V reference voltage. 0.1uF or greater capacitor to GND is needed for noise filtering. 14 Vdd2 Bias supply for negative voltage generator. Connect supply voltage with appropriate filtering. Vdd2 supply voltage should be same as Vdd1. 15 CPOUT Negative voltage generator charge pump output. Negative voltage generator needs a flying capacitor, a reservoir capacitor and two diodes to operate. Please refer to the application schematic for more info. 16 DGND Digital ground domain (DGND). 11, 17 AGND Analog ground domain (GND). 18 VNEGFB Feedback (Control) pin for Negative Voltage Generator Charge Pump. Float to activate the negative voltage generator / Sort to GND to disable the negative voltage generator. VNEGIN Negative input to the chip. Should be supplied with CPOUT when negative voltage generator is enabled, or connect to external VSS when negative voltage generator is enabled. For detailed usage please refer to the “Negative Voltage Generator” section. VGATEFB Control pin for VGATEFB. Float VGATEFB when a depletion mode transistor is biased. Selects the mode of operation along with VNEGFB pin. For detailed usage please refer to the Table 1. Mode Selection. 19 20 Interface Schematic For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com 13 DC POWER MANAGEMENT - SMT Pin Number 13 - 8 HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Pin Descriptions (Continued) Pin Number Function Description 21 VGATE Gate Control pin for external amplifier. Connect to the gate (base) of the external amplifier. In order to guarantee stability, a 10µF capacitor should be connected between the gate (base) terminal of the external amplifier and GND as close to the amplifier as possible. 22, 23 VDRAIN Drain voltage. Should be connected to the supply terminal of the external amplifier. A minimum 100 nF capacitor has to be placed close to the external amplifier to improve load regulation. 25 ISENSE To adjust the bias current of the external amplifier connect a resistor (Rsense) from ISENSE pin to GND. Use Eqn.4 to determine the required Rsense value. 26 ALML A high precision resistor (e.g. 0.5%, ±25 ppm TCR) to GND is needed. The value of the resistor sets the threshold value for under current alarm. Please refer to the “Over/ Under Current Alarm” section for a detailed explanation. ALMM A high precision resistor (e.g. 0.5%, ±25 ppm TCR) between ALML and ALMM is needed. The total external resistance from ALMM pin to GND should always be equal to 5 kΩ. Please refer to the “Over/Under Current Alarm” section for a detailed explanation. ALMH A high precision resistor (e.g. 0.5%, ±25 ppm TCR) to ALMM pin is needed. The value of the resistor sets the threshold value for over current alarm. Please refer to the “Over/Under Current Alarm” section for a detailed explanation. DC POWER MANAGEMENT - SMT 13 27 28 13 - 9 Interface Schematic For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Pin Descriptions (Continued) Function Description 29 LDOCC High voltage LDO output pin. To ensure stability, connect a 10 µF capacitor with ESR>200 mΩ from LDOCC to GND. A tantalum capacitor is recommended to meet the ESR requirement. 30 LDOFB Feedback pin of the VDRAIN LDO. VDRAIN voltage is set by two resistors calculated with Eqn. 2. 32 VddCHK Should be left floating for regular operation. Paddle GND PAD Analog ground (AGND). Interface Schematic For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com 13 DC POWER MANAGEMENT - SMT Pin Number 13 - 10 HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Simplified Application Circuit DC POWER MANAGEMENT - SMT 13 Notes: [1] A variable resistor is assembled on R4 slot to adjust bias current for evaluating various different amplifiers without soldering. [2] A variable resistor is assembled on R1 slot to adjust VDRAIN voltage for evaluating various different amplifiers without soldering. 13 - 11 For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Simplified Evaluation PCB List of Materials for Simplified Evaluation PCB EVAL01-HMC920LP5E [1] Item Description TP1-TP6 DC Test Point C1 100 nF Capacitor, 0402 Pkg. C2, C7 10 µF Capacitor, Case B Tantalum C3 22 µF Capacitor, Tantalum. C4 100 pF Capacitor, 0402 Pkg. C5, C10 4.7 µF Capacitor, 0603 Pkg. C6, C11 10 µF Capacitor, 0603 Pkg. C9 330 nF Capacitor, 0603 Pkg. D1 Dual Schottky Diode (Digi-Key part number: BAT54SLT1) R1 50k Ohm Trim Potentiometer R4 5k Ohm Trim Potentiometer R2, R13 10k Ohm Resistor, 0402 Pkg. R6 4.99k Ohm, 0402 Pkg. R7 270 Ohm, 0402 Pkg. U1 HMC920LP5E Active Bias Controller PCB [2] EVAL01-HMC920LP5E Evaluation PCB DC POWER MANAGEMENT - SMT 13 [1] Reference this number when ordering complete evaluation PCB [2] Circuit Board Material: FR4 For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com 13 - 12 HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Full Featured Application Circuit DC POWER MANAGEMENT - SMT 13 Notes: [1] A variable resistor is assembled on R19 slot to adjust bias current for evaluating various different amplifiers without soldering. [2] A variable resistor is assembled on R10 slot to adjust VDRAIN voltage for evaluating various different amplifiers without soldering. [3] SW2’s function is to ENABLE and DISABLE the “Active Bias Control” function of the HMC920LP5E. 13 - 13 For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Full Featured Evaluation PCB List of Materials for Full Featured Evaluation PCB 130511 [1] Item Description Item Description TP2, TP8 - TP11, TP14, TP15, TP17 DC Test Point D1 Dual Schottky Diode (Digi-Key part number: BAT54SLT1GOSCT-ND) C2 47 pF Capacitor, 0402 Pkg. SW1 DIP 4 Position Half-Pitch Switch C5, C9 10 µF Capacitor, Case B Tantalum SW2 DIP 2 Position Half-Pitch Switch C6, C14 4.7 µF Capacitor, 0805 Pkg. U1 HMC920LP5E Active Bias Controller C12, C21 10 µF Capacitor, 0805 Pkg. PCB [2] 128399 Evaluation PCB C13 0.33 µF Capacitor, 0603 Pkg. [1] Reference this number when ordering complete evaluation PCB C19 22 µF Capacitor, Tantalum [2] Circuit Board Material: FR4 C20 0.1 µF Capacitor, 0402 Pkg. C22 0.1 µF Capacitor, 0805 Pkg. C24 100 pF Capacitor, 0603 Pkg. R2, R29 0 Ohm Resistor, 0805 Pkg. R4 270 Ohm Resistor, 0402 Pkg. R5, R26 10 kOhm Resistor, 0603 Pkg. R10 50 kOhm Potentiometer R14 1 kOhm Resistor, 0603 Pkg. R15 3.32 kOhm Resistor, 0603 Pkg. R16 1.69 kOhm Resistor, 0603 Pkg. R19 5 kOhm Potentiometer R20, R22 1.8M Ohm Resistor, 0603 Pkg. R27 10 kOhm 0.5% ±25ppm/°C Resistor, 0402 Pkg. R28 0 Ohm Resistor, 0402 Pkg. Careful PCB layout is critical to achieve stable and low noise operation. The negative voltage generator charge pump stage requires particular attention. To isolate the charge pump switching noise from the analog circuit blocks, create two separate ground planes dedicated to AGND and DGND connections. Connect AGND (pin#17) and DGND (pin#16) pins to the paddle at a single point under the package. Connect all the components connected to the charge pump (D1, C12 and C14 in the application circuit) to DGND plane, and connect rest of the external components to a low noise AGND. For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com DC POWER MANAGEMENT - SMT 13 13 - 14 HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Application Notes Detailed Description HMC920LP5E is an active bias controller which can be configured to provide the supply voltage and adjust the gate voltage of an external amplifier to achieve constant bias current. It can be used to bias both enhancement and depletion type amplifiers. The HMC920LP5E achieves excellent bias stability over supply and temperature variations. The gate control can both sink and source current (±4 mA) to achieve constant bias current over input power variations. The HMC920LP5E standard application circuit generates 3.5V digital supply voltage (VDIG) for internal use, and -2.5V negative voltage (VNEG) for depletion mode devices. If an external negative supply is already available or an enhancement mode device is targeted, the negative voltage generator can be disabled. DC POWER MANAGEMENT - SMT 13 13 - 15 HMC920LP5E controls the bias current of the external amplifier with the gate control block. The current passing through the external amplifier is sampled and is used to control the VGATE voltage connected to the gate of the external amplifier to achieve constant quiescent bias through the external amplifier. This active bias control continuously adjusts the VGATE voltage to achieve constant bias current through the targeted amplifier independent of supply, temperature, process variations, and threshold shifts due to aging. HMC920LP5E ensures safety of the external amplifier during turn on/off by adjusting the sequence of VDRAIN and VGATE outputs. The current passing through the external amplifier is monitored continuously. If a fault conditions arises (either under or over current) an alarm signal is generated (CURALM, active HIGH). A different alarm signal is generated (VddALM, active LOW) if the HMC920LP5E supply voltage drops below a certain threshold. Both supply voltage and current alarm signals provided in HMC920LP5E does not affect the operation of the controller. Both alarms has designed for monitoring purposes where a system level protection can be implemented with external control circuitry. The HMC920LP5E has power foldback and short circuit protection features. Typical Application Diagram The HMC920LP5E is a system on chip solution for the biasing needs of RF amplifiers and it has several functional blocks (see functional block diagram on the first page), to achieve the features summarized above. Refer to the section of the specific functional block for the detailed operation and adjustment descriptions. For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Low Voltage Linear Regulator (VDIG) The HMC920LP5E requires a low voltage bias rail (3.3V to 5V) for internal circuitry. An internal linear regulator produces a preset 3.5V low-current VDIG output. VDIG powers the internal logic circuitry, oscillator and the control of the negative charge pump. VDIG supplies a maximum of 30mA current and therefore it is recommended for external use only for light loading. If needed the VDIG output can be adjusted externally through R1 and R3, to a maximum of 5V. To adjust the VDIG value, set R1 to 10kΩ and determine the value of R3 using the equation (1): (1) Place the R1 and R3 resistor as close as possible to the VDIG FB pin. To ensure stable operation of VDIG, bypass VDIG to AGND with a 10µF tantalum capacitor (with RESR > 200mΩ) under full-load conditions. Figure 1. Low Voltage Linear Regulator (VDIG) Block Diagram If a 3.3V/5V supply is already available externally, internal low-voltage regulator can be disabled to increase the overall system efficiency. To deactivate the internal low-voltage regulator, connect a 0Ohm resistor on R3 (depopulate R1), and connect the external supply to VDIG pin. The typical current consumption from VDIG pin is less than 5mA. The correct power up sequence is GND, VDD, VDIG, VNEG, and signal pins. Reference (BGCAP) The HMC920LP5E employs two reference voltage generators. The first reference voltage generates 2.5V accurate to ±5% over temperature, supply, and load variations.. This reference voltage generator is used to bias VDIG LDO. A second reference generator generates a stable 2V reference accurate to ±2% over temperature, supply, and load variations. In order to decrease noise, it is recommended to bypass BGCAP to AGND with a 0.1μF or greater ceramic capacitor, as close as possible to the BGCAP pin as possible. For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com 13 DC POWER MANAGEMENT - SMT R3 = R1 x (VDIG - 2.5) 2.5 13 - 16 HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER High Voltage Linear Regulator (LDOCC/VDRAIN) The HMC920LP5E has an adjustable high-voltage, high-current linear regulator (LDOCC) to provide the drain supply rail of the external RF amplifier. The LDOCC output can source up to 500mA loads. The LDOCC output can be adjusted to regulate any voltage level from 3V to 15V through external resistors R8 and R5. To adjust the LDOCC, set R5 to 10kΩ and determine the value of R8 using the equation (2): R8 = R5 x (VDOCC - 2) (2) 2 Place the R8 and R5 as close as possible to the LDOFB. The LDOCC output is connected to the VDRAIN output through an internal MOSFET (RDS-ON = 0.5Ω) switch. DC POWER MANAGEMENT - SMT 13 This internal MOSFET is controlled through power-up sequencing which ensures that no voltage is applied to drain of the external amplifier until the gate voltage is pulled down to VNEG(ensuring external amplifier disabled). Connect the external amplifier to the VDRAIN output to use power-up sequencing feature. Note that there will be a voltage drop from LDOCC to VDRAIN due to finite RDS_ON resistance of the internal switch. To compensate for this voltage drop choose the LDOCC value as shown in equation (3). VLDOCC = VDRAIN + IDRAIN x 0.5 (3) Where VDRAIN is the supply voltage of the external amplifier and IDRAIN is the desired constant bias current through the external amplifier. To ensure stable operation of the LDOCC output, bypass LDOCC to AGND with a 10µF tantalum capacitor (with RESR > 200mΩ). The HMC920LP5E has power foldback and short circuit protection, refer to the respective section for detailed description of these features. Negative Voltage Generator (VNEGOUT) The HMC920LP5E has an internal regulated charge pump block to generate negative voltage (VNEGOUT) required for depletion mode devices. The HMC920LP5E generates -2.5V at the VNEGOUT output in default configuration. Contact factory if a voltage rail different than -2.5V is required. The HMC920LP5E is designed to reject the ripple on the VNEGOUT by isolating VNEGOUT from the VGATE. The negative voltage is required only for depletion mode devices, and it can be disabled through the VGATEFB and VNEGFB pins. See Table-1 how to set the operation mode. Enable/Disable (EN) The active bias control loop is enabled when EN is pulled up to VDIG, and it is disabled when it is pulled down to GND. If EN is left floating HMC920LP5E is enabled through the internal weak pull-up. Note that LDOCC, VDIG and VNEG operation is independent of EN condition. EN signal controls the operation of only VGATE and VDRAIN outputs. When EN pulled down to GND, HMC920LP5E discharges VDRAIN down to GND and it pulls the VGATE down to VNEG. Please see the “Active Bias Control Loop” section for detailed explanation. 13 - 17 For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Active Bias Control Loop The HMC920LP5E regulates the bias current (IDRAIN) of the external amplifier through VGATE output connected to the gate of the external amplifier. In this closed loop operation the current passing through the external amplifier is sampled and is used to adjust VGATE to achieve constant quiescent bias through the external amplifier. The HMC920LP5E continuously compensates for any supply, temperature, process variations and threshold drifts due to aging, without any calibration. The gate control of the HMC920LP5E can both sink and source current (at least ±4 mA) to achieve constant bias current over input power variations. RSENSE adjustment is referenced to the total resistance seen from ALMM (PIN#27) to GND. Connect 5 kΩ resistor from ALMM to GND (R16 + R15) to ensure equation (4) holds. Power Foldback The HMC920LP5E employs a power foldback protection feature to limit the power consumption on the HMC920LP5E package under excessive loading such as a short circuit from VDRAIN to GND. HMC920LP5E senses the instantaneous power consumption over the VDRAIN LDO (PSENSE = (Vdd-VDRAIN) x IDRAIN), and limits the instantaneous power consumption less than 4.5W. This is achieved by decreasing VDRAIN voltage and IDRAIN current simultaneously. The advantage of the power foldback protection feature over a hard current limit is safe operation with higher user flexibility. The following plots present the power foldback characteristic over Vdd. Power Foldback VDRAIN vs. IDRAIN over Vdd Power Foldback Delivered Power vs. IDRAIN Over Vdd POWER DELIVERED FROM VDRAIN (W) 4 VDRAIN (V) 3 2 Vdd = 6V Vdd = 9V Vdd = 12V Vdd = 15V 1 0 0 100 200 300 400 500 IDRAIN (mA) 600 700 800 2.5 Vdd = 6V Vdd = 9V Vdd = 12V Vdd = 15V 2 13 DC POWER MANAGEMENT - SMT The bias current passing through the external amplifier can be adjusted with RSENSE, where RSENSE is the total resistor (R4 + R19) connected from ISENSE to GND. Use the relation given in equation (4) to set the desired bias current through the external amplifier. IDRAIN = 165 A (4) RSENSE 1.5 1 0.5 0 0 100 200 300 400 500 600 700 800 IDRAIN (mA) For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com 13 - 18 HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Power Dissipated on HMC920LP5E vs. IDRAIN Over Vdd POWER DISSIPATED (W) 5 DC POWER MANAGEMENT - SMT 13 4 3 2 Vdd = 6V Vdd = 9V Vdd = 12V Vdd = 15V 1 0 0 100 200 300 400 500 600 700 800 IDRAIN (mA) Short Circuit Protection The pass transistor in every LDO is in series with the load, and a large amount of current will flow through the regulator during a short condition when no precaution circuitry is included in the system. The HMC920LP5E limits the current through the pass transistor to less than 900 mA, and this current limit acts as the secondary short circuit protection to the power foldback feature. During a VDRAIN-GND short circuit HMC920LP5E also pulls down the VGATE to the lowest voltage supply VNEG, and disables the external amplifier completely for safety. HMC920LP5E continuously checks the following pins for short conditions and disables the system when a short to ground is detected. -LDOCC -VDRAIN -VNEGIN (in depletion mode) -FIXBIAS Over/Under Current Alarm The HMC920LP5E provides over and under current alarm indicator CURALM (pin#8) signal. The CURALM is pulled up to VDIG when the IDRAIN current exceeds ± 25% of IDRAIN regulation target value. The condition of CURALM signal does not effect the operation of HMC920LP5E, it is provided only for monitoring purposes. The CURALM signal is activated if the low and high current duration is longer than a certain threshold. This duration can be adjusted through the external resistor R26 with equation 5. Figure-2 presents a behavioral sketch how the CURALM indicator signal acts under various IDRAIN conditions. Twait = R26x5.1x10 -4+3 where Twait is in micro seconds. Changing R26 from 10 kOhms to 10 Megohms, Twait can be adjusted from 8.1 usec to 51 msec. 13 - 19 For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Figure 2. Current Alarm Behavior Vdd Under-Voltage Alarm The HMC920LP5E provides a low Vdd indicator signal (VddALM pin#31) when the Vdd supply voltage is lower than an user adjustable threshold value. VddALM pin pulled down to GND when the Vdd voltage is lower than the adjusted VddTHR value. To adjust the Vdd under-voltage alarm threshold set R6 (the resistance from VddCHK to AGND) according to the relation provided in (6). R6 Power-up and Enable Sequencing 150k VddTHR 13 3 0.88 (6) To ensure the safety of the external amplifier the HMC920LP5E provides a certain power-up sequence for enabling active bias control loop. During start-up VDRAIN is kept at GND while VGATE is taken to the most negative supply available (VGATE=VNEG). This ensures that external amplifier is completely turned-off before VDRAIN is applied. When EN signal is received VDRAIN is applied and the active bias loop is enabled. The final phase of the power-up sequence is completed by increasing the VGATE linearly until the set IDRAIN value is achieved. For power-down and disabling the same sequencing is applied in the reverse order. Daisy-Chain Operation HMC920LP5E produces a trigger out signal (TRGOUT pin#24) when the external amplifier achieves a stable bias current (IDRAIN). This trigger signal can be used to enable additional HMC920LP5E chips in a chain of amplifiers. The triggering sequence can be routed in anyway, from input to output, or from output to input depending on the use. Figure-3 presents a sample use of three HMC920LP5Es in an amplifier chain. Please note that, only one of the HMC920LP5E is used to generate the negative voltage and the remaining HMC920LP5E is set to receive external negative voltages (which is provided from the master HMC920LP5E). Generating negative voltage only with single HMC920LP5E reduces the number of the components in the system, and decreases the over all current consumption slightly, compared to each bias controller generating its own negative voltage. DC POWER MANAGEMENT - SMT 13 To ensure proper start-up, the system enable signal should ne applied to the chip that has the negative voltage generator. For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com 13 - 20 HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER DC POWER MANAGEMENT - SMT 13 Figure 3. Daisy Chain Operation Operation Modes HMC920LP5E can be configured to bias both enhancement and depletion mode external amplifiers. The mode of operation can be selected by setting two pins (VNEGFB, VGATEFB) as tabulated in Table-1. The connection to the VNEGIN should be adjusted accordingly. In order not to bias external amplifier in a wrong region, please make sure that the correct mode of operation is selected before powering up HMC920LP5E. HMC920LP5E does not allow the internal negative voltage generator to work if an enhancement mode is selected. Therefore, if VNEGFB is left floating while VGATEFB is grounded, HMC920LP5E will stay in standby mode. Please note that the external negative voltage should be between -2.5V to -3.5V for HMC920LP5E to operate. Table 1. Mode Selection VNEGFB MODE1 (Depletion/Master Mode) MODE2 (Depletion/Slave Mode) --MODE3 (Enhancement Mode) 13 - 21 VNEGIN Description FLOAT Connected to VNEGOUT Depletion mode transistor. Internal negative voltage generator is active and generates -2.5V. Sample application schematic given shown in Fig.4a. GND FLOAT Connected to External VSS Depletion mode transistor. Internal negative voltage generator is disabled. An external negative voltage less than -2.3V should be connected to VNEGIN. Sample application schematic given shown in Fig.4b. FLOAT GND N/A Not allowed. HMC920LP5E stays in standby. GND Connected to GND Enhancement mode transistor. Internal negative voltage generator is disabled. Sample application schematic given shown in Fig.5. FLOAT GND VGATEFB For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Figure 4a: Depletion/Master Mode Amplifier Typical Application Circuit (Mode 1) DC POWER MANAGEMENT - SMT 13 For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com 13 - 22 HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Figure 4b: Depletion/Slave Mode Amplifier Typical Application Circuit (Mode 2) DC POWER MANAGEMENT - SMT 13 13 - 23 For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Figure 5: Enhancement Mode Amplifier Typical Application Circuit (Mode 3) DC POWER MANAGEMENT - SMT 13 For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com 13 - 24 HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Table 2 - List of Bias Settings for Various Hittite Amplifiers Hittite Part Number VDRAIN (V) IDRAIN (mA) LDOCC (V) RSENSE (kΩ) R8 (kΩ) LNAs 13 HMC609LC4 6 170 6.09 1.0 20.4 HMC594LC3B 6 100 6.05 1.7 20.3 HMC753LP4 5 55 5.03 3.0 15.1 HMC490LP5 5 200 5.10 0.8 15.5 HMC504LC4B 4 90 4.05 1.8 10.2 HMC-ALH140 4 60 4.03 2.8 10.2 HMC-ALH244 4 45 4.02 3.7 10.1 HMC772LC4 4 45 4.02 3.7 10.1 HMC752LC4 3 70 3.04 2.4 5.2 Gain Blocks & Drivers HMC635LC4 5 280 5.14 0.6 15.7 HMC-AUH256 5 295 5.15 0.6 15.7 DC POWER MANAGEMENT - SMT Linear & Power 13 - 25 HMC757 7 395 7.20 0.4 26.0 HMC441LM1 5 90 5.05 1.8 15.2 HMC442LM1 / HMC442LC3B 5 85 5.04 1.9 15.2 HMC-ABH209 5 80 5.04 2.1 15.2 HMC-APH403 5 475 5.24 0.3 16.2 HMC-APH596 5 400 5.20 0.4 16.0 HMC608LC4 5 310 5.16 0.5 15.8 HMC498LC4 5 250 5.13 0.7 15.6 HMC-ABH241 5 220 5.11 0.8 15.6 HMC499LC4 5 200 5.10 0.8 15.5 HMC-APH196 4.5 400 4.70 0.4 13.5 HMC-APH633 4 240 4.12 0.7 10.6 HMC-AUH317 4 160 4.08 1.0 10.4 HMC-AUH318 4 160 4.08 1.0 10.4 HMC-AUH320 4 130 4.07 1.3 10.3 HMC863 6 375 6.19 0.4 20.9 HMC637LP5 12 400 12.20 0.4 51.0 HMC619LP5 12 300 12.15 0.6 50.8 HMC559 10 400 10.20 0.4 41.0 HMC562 8 80 8.04 2.1 30.2 Wideband (Distributed) HMC460LC5 8 75 8.04 2.2 30.2 HMC659LC5 8 300 8.15 0.6 30.8 HMC464LP5 8 290 8.15 0.6 30.7 HMC459 8 290 8.15 0.6 30.7 HMC465LP5 8 160 8.08 1.0 30.4 HMC462LP5 5 66 5.03 2.5 15.2 For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com HMC920LP5E v05.0911 ACTIVE BIAS CONTROLLER Table 2 - List of Bias Settings for Various Hittite Amplifiers (Continued) VDRAIN (V) IDRAIN (mA) LDOCC (V) RSENSE (kΩ) R8 (kΩ) HMC463LP5 Hittite Part Number 5 60 5.03 2.8 15.2 HMC635 5 280 5.14 0.6 15.7 HMC634LC4 5 180 5.09 0.9 15.5 HMC633LC4 5 180 5.09 0.9 15.5 HMC795LP5E 10 400 10.20 0.4 41.0 Microwave & Optical Drivers HMC870LC5 7 165 7.08 1.0 25.4 HMC871LC5 8 75 8.04 2.2 30.2 DC POWER MANAGEMENT - SMT 13 For price, delivery, and to place orders, please contact Hittite Microwave Corporation: 20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373 Order On-line at www.hittite.com 13 - 26