LT6557 500MHz, 2200V/µs Gain of 2, Single Supply Triple Video Amplifier with Input Bias Control FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTION –3dB Small-Signal Bandwidth: 500MHz –3dB 2VP-P Large-Signal Bandwidth: 400MHz Slew Rate: 2200V/µs Fixed Gain of 2, No External Resistors Required AC Coupling with Programmable DC Input Bias Output Swings to 0.8V of Supply Rails Full Video Swing with 5V Single Supply Diff Gain: 0.02% Diff Phase: 0.05° Enable/Shutdown Pin High Output Current: ±100mA Supply Range: 3V to 7.5V Operating Temperature Range: –40°C to 85°C Available in 16-Lead SSOP and 5mm × 3mm DFN Packages APPLICATIONS ■ ■ ■ ■ LCD Video Projectors RGB HD Video Amplifiers Coaxial Cable Drivers Low Supply ADC Drivers The LT®6557 is a high speed triple video amplifier with an internal fixed gain of 2 and a programmable DC input bias voltage. This amplifier features a 400MHz 2VP-P signal bandwidth, 2200V/µs slew rate and a unique ability to drive heavy output loads to 0.8V of the supply rails, making the LT6557 ideal for a single 5V supply, wideband video application. With just one resistor, the inputs of all three amplifiers can be programmed to a common voltage level, simplifying and reducing the need for external circuitry in the AC-coupled applications. Without the programmable resistor, the input bias circuit becomes inactive, allowing the use of an external clamp circuit or direct coupled input. The LT6557 has separate power supply and ground pins for each amplifier to improve channel separation and to ease power supply bypassing. The LT6557 provides uncompromised performance in many high speed applications where a low voltage, single supply is required. The LT6557 is available in 16-lead SSOP and 5mm × 3mm DFN packages. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION AC-Coupled Triple Video Driver GND Fast Large-Signal Transient Response BCV EN LT6557 V+ 5V 412Ω 22µF IN R IN R 75Ω GND R 500Ω + – OUT R 500Ω V+ R 75Ω 220µF 75Ω 5V 22µF IN G IN G 75Ω GND G 500Ω + – OUT G 500Ω V+ G 75Ω 220µF 75Ω 5V 22µF IN B IN B 75Ω GND B 500Ω + – OUT B 500Ω V+ B 75Ω 220µF 75Ω 5V 6557 TA01a 6557fa 1 LT6557 ABSOLUTE MAXIMUM RATINGS (Note 1) Total Supply Voltage (VS+ to GND) ...........................7.5V Input Current........................................................±10mA Output Current (Note 2) .......................................±70mA Output Short-Circuit Duration (Note 2) ............ Indefinite Operating Temperature Range (Note 3) ... –40°C to 85°C Specified Temperature Range (Note 4) .... –40°C to 85°C Junction Temperature SSOP ................................................................ 150°C DFN ................................................................... 125°C Storage Temperature Range SSOP ................................................. –65°C to 150°C DFN.................................................... –65°C to 125°C Lead Temperature (Soldering, 10 sec) SSOP ................................................................ 300°C PACKAGE/ORDER INFORMATION TOP VIEW TOP VIEW EN 1 GND 2 IN R 3 GND R 4 IN G 5 GND G 6 IN B 7 GND B 16 BCV G = +2 15 V+ 14 OUT R G = +2 13 V+ R 12 OUT G G = +2 8 11 V+ G 10 OUT B 9 V+ B EN 1 GND 2 16 BCV 17 G = +2 15 V+ 14 OUT R IN R 3 GND R 4 IN G 5 GND G 6 IN B 7 10 OUT B GND B 8 9 G = +2 13 V+ R 12 OUT G G = +2 11 V+ G V+ B DHC PACKAGE 16-LEAD (5mm × 3mm) PLASTIC DFN TJMAX = 125°C, θJA = 40°C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB GN PACKAGE 16-LEAD PLASTIC SSOP TJMAX = 150°C, θJA = 110°C/W ORDER PART NUMBER GN PART MARKING ORDER PART NUMBER DHC PART MARKING* LT6557CGN LT6557IGN 6557 6557I LT6557CDHC LT6557IDHC 6557 6557 Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 5V, RL = 150Ω to VS/2, VEN = 0.4V, RBCV = open, unless otherwise noted. SYMBOL PARAMETER CONDITIONS VOS Input Offset Voltage VIN = 1.25V IIN Input Current RIN Input Resistance CIN Input Capacitance VIN = 1.25V VIN = 0.75V to 1.75V, BCV (Pin 6) Open f = 1MHz MIN TYP MAX ● 12 15 40 50 mV mV ● 35 45 70 100 µA µA ● 90 50 200 150 1.5 UNITS kΩ kΩ pF 6557fa 2 LT6557 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 5V, RL = 150Ω to VS/2, VEN = 0.4V, RBCV = open, unless otherwise noted. SYMBOL PARAMETER CONDITIONS AV ERR Gain Error VIN = 0.75V to 1.75V AV MATCH Gain Match Between Channels VIN(DC) Input Voltage Bias PSRR Power Supply Rejection Ratio VOL Output Voltage Swing Low VOH Output Voltage Swing High IS Supply Current per Amplifier MIN VIN = 0.75V to 1.75V RBCV = 348Ω VS = 4V to 6V, VIN = 1.25V TYP MAX UNITS ● ±0.5 ±0.5 ±2.5 ±3.0 % % ● ±0.4 ±0.4 ±2.75 ±3.25 % % 1.5 1.7 V V ● 1.0 0.8 1.25 1.10 ● 42 38 50 47 0.8 0.9 ● ● Total Supply Current (Disabled) VEN = 0.4V, RL = ∞, Includes IS of V+ (Pin 15) VEN = Open, RL = ∞ IEN Enable Pin Current ISC Short-Circuit Current SR Slew Rate VOUT = 1.25V to 3.75V (Note 5) –3dB BW –3dB Bandwidth VEN = 0.4V 4.1 4.0 dB dB 0.9 1.0 4.2 4.1 V V V V ● 22.5 25.0 25 29 mA mA ● 10 10 450 1000 µA µA ● –250 –300 –125 –150 µA µA ● ±70 ±40 ±100 ±90 mA mA 1400 2200 V/µs VOUT = 2VP-P 400 MHz VOUT = 0.2VP-P 500 MHz 120 MHz 350 MHz 0.1dB BW Gain Flatness ±0.1dB Bandwidth VOUT = 2VP-P FPBW Full Power Bandwidth VOUT = 2VP-P (Note 6) XTalk All Hostile Crosstalk f = 10MHz, VOUT = 2VP-P f = 100MHz, VOUT = 2VP-P –80 –55 dB dB tS Settling Time To 1%, VOUT = 1.5V to 3.5V To 0.1% 4 7 ns ns tr, tf Rise Time, Fall Time 10% to 90%, VOUT = 1.5V to 3.5V 875 ps ΔG Differential Gain NTSC Signal 0.02 % ΔΦ Differential Phase NTSC Signal 0.05 Deg HD2 2nd Harmonic Distortion f = 10MHz, VOUT = 2VP-P –68 dBc HD3 3rd Harmonic Distortion f = 10MHz, VOUT = 2VP-P –75 dBc Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: A heat sink may be required to keep the junction temperature below the Absolute Maximum Rating. Note 3: The LT6557C is guaranteed functional over the temperature range of –40°C and 85°C. Note 4: The LT6557C is guaranteed to meet specified performance from 0°C to 70°C. The LT6557C is designed, characterized and expected to 220 meet specified performance from –40°C to 85°C but is not tested or QA sampled at these temperatures.The LT6557I is guaranteed to meet specified performance from –40°C to 85°C. Note 5: Slew rate is 100% production tested on the R channel and measured on the rising edge of the output signal. The slew rate of the falling edge and of the G and B channels is guaranteed through design and characterization. Note 6: Large-signal bandwidth is calculated from slew rate: FPBW = SR/(π • VP-P) 6557fa 3 LT6557 TYPICAL PERFORMANCE CHARACTERISTICS Gain Error Distribution Gain Error Matching Distribution Voltage Gain vs Temperature Supply Current per Ampifier vs Supply Voltage Supply Current per Ampifier vs Temperature Supply Current per Ampifier vs EN Voltage Input Referred Offset Voltage vs Temperature Input Bias Current vs Input Voltage 50 VOUT = VS/2 45 SUPPLY CURRENT (mA) 40 35 30 25 20 15 10 5 0 0 1 2 6 3 4 5 SUPPLY VOLTAGE (V) 7 8 6557 G04 EN Pin Current vs EN Pin Voltage 6557fa 4 LT6557 TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage vs Input Voltage Output Voltage Swing vs Load Current (Output High) Output Voltage Swing vs Load Current (Output Low) Input Bias Voltage vs Resistance at BCV Pin Input Bias Voltage vs Temperature Bias Control Voltage vs Temperature Frequency Response Frequency Response of Three Amplifiers Gain Flatness vs Frequency 6557fa 5 LT6557 TYPICAL PERFORMANCE CHARACTERISTICS Frequency Response with Capacitive Loads Output Impedance vs Frequency Distortion vs Frequency Large-Signal Group Delay Input Impedance vs Frequency Distortion vs Frequency Crosstalk Between Amplifiers vs Frequency PSRR vs Frequency Input Referred Noise Spectral Density 6557fa 6 LT6557 TYPICAL PERFORMANCE CHARACTERISTICS Overdriven Output Recovery Enable/Disable Response 6 5 VEN(DISABLE) 5 VOUT 4 VS = 5V VOUT = 2VP-P AC COUPLED RL = 150W 4 VOLTAGE (V) VIN = 0.5V/DIV, VOUT = 1V/DIV VIN 3 2 3 2 VOUT 1 1 0 VS = 5V VIN = 2.4VP-P RL = 1509 0 0 VEN(ENABLE) –1 25 50 75 100 125 150 175 200 225 250 TIME (ns) 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 TIME (ms) 6557 G28 6557 G29 Large-Signal Transient Response Small-Signal Transient Response 2.65 VS = 5V VIN = 50mVP-P RL = 1509 OUTPUT (V) 2.60 2.55 2.50 2.45 0 2 4 6 8 10 12 14 16 18 20 22 24 TIME (ns) 6557 G31 PIN FUNCTIONS EN (Pin 1): Enable Control Pin. The part is enabled when this pin is pulled low. An internal pull-up resistor of 40k will turn the part off if this pin is unconnected. IN G (Pin 5): Green Channel Input. This pin has a nominal impedance of 200kΩ with input bias circuit inactive, Pin 16 open. GND (Pin 2): Ground Reference for Enable Pin (Pin 1) and Bias Control Voltage Pin (Pin 16). This pin must be connected externally to ground. GND G (Pin 6): Ground of Green Channel Amplifier. This pin is not internally connected to other ground pins and must be connected externally to ground. IN R (Pin 3): Red Channel Input. This pin has a nominal impedance of 200kΩ with input bias circuit inactive, Pin 16 open. IN B (Pin 7): Blue Channel Input. This pin has a nominal impedance of 200kΩ with input bias circuit inactive, Pin 16 open. GND R (Pin 4): Ground of Red Channel Amplifier. This pin is not internally connected to other ground pins and must be connected externally to ground. GND B (Pin 8): Ground of Blue Channel Amplifier. This pin is not internally connected to other ground pins and must be connected externally to ground. 6557fa 7 LT6557 PIN FUNCTIONS V+ B (Pin 9): Positive Supply Voltage of Blue Channel Amplifier. This pin is not internally connected to other supply voltage pins and must be externally connected to the supply voltage bus with proper bypassing for best performance, see Power Supply Considerations. OUT B (Pin 10): Blue Channel Output. V+ G (Pin 11): Positive Supply Voltage of Green Channel Amplifier. This pin is not internally connected to other supply voltage pins and must be externally connected to the supply voltage bus with proper bypassing for best performance, see Power Supply Considerations. the supply voltage bus with proper bypassing for best performance, see Power Supply Considerations. OUT R (Pin 14): Red Channel Output. V+ (Pin 15): Positive Supply Voltage of Control Circuitry. This pin is not internally connected to other supply voltage pins and must be externally connected to supply voltage bus with proper bypassing for best performance, see Power Supply Considerations. OUT G (Pin 12): Green Channel Output. BCV (Pin 16): Bias Control Voltage. A resistor connected between Pin 16 and Pin 2 (GND) will generate a DC voltage bias at the inputs of the three amplifiers for AC coupling application, see Programmable Input Bias. V+ R (Pin 13): Positive Supply Voltage of Red Channel Amplifier. This pin is not internally connected to other supply voltage pins and must be externally connected to Exposed Pad (Pin 17, DFN Package): Ground. This pad must be soldered to PCB and is internally connected to GND (Pin 2). APPLICATIONS INFORMATION Power Supply Considerations The LT6557 is optimized to provide full video signal swing output when operated from a standard 5V single supply. Due to the supply current involved in ultrahigh slew rate amplifiers like the LT6557, selection of the lowest workable supply voltage is recommended to minimize heat generation and simplify thermal management. Temperature rise at the internal devices (TJ) must be kept below 150°C (SSOP package) or 125°C (DFN package), and can be estimated from the ambient temperature (TA) and power dissipation (PD) as follows: TJ = TA + PD • 40°C/W for DFN package or TJ = TA + PD • 110°C/W for SSOP package where PD = (IS + 0.5 • IO) • VS(TOTAL) The latter equation assumes (conservatively) that the output swing is small relative to the supply and RMS load current (IO) is bidirectional (as with AC coupling). The grounds are separately pinned for each amplifier to minimize crosstalk. Operation from split supplies can be accomplished by connecting the LT6557 ground pins to the negative rail. Since the amplifier gain is referenced to its ground pins, the actual signals are referenced to the negative rail, in this case, and DC coupled applications need to take this into consideration. With dual supplies, recommended voltages range from nominal ±2.5V to ±3.3V. The ultrahigh frequency (UHF) operating range of the LT6557 requires that careful printed circuit layout practices be followed to obtain maximum performance. Trace lengths between power pins and bypass capacitors should be minimized (<0.1 inch) and one or more dedicated ground planes should be employed to minimize parasitic inductance. Poor layout or breadboarding methods can seriously impact amplifier stability, frequency response and crosstalk performance. A 2.2µF and a 10µF bypass capacitor is recommended for the LT6557supply bus, plus a 10nF high frequency bypass capacitor at each individual power pin. 6557fa 8 LT6557 APPLICATIONS INFORMATION Programmable Input Bias The LT6557 contains circuitry that provides a user-programmed bias voltage to the inputs of all three amplifier sections. The internal biasing feature is designed to minimize external component count in AC-coupled applications, but may be defeated if external biasing is desired. Figure 1 shows the simplified equivalent circuit feeding the noninverting input of each amplifier. A programming resistor from Pin 16 to GND (Pin 2) establishes the nominal V+ V I = PIN16 RSET no-signal amplifier input bias condition according to the following relationship: VBIAS(IN) = VPIN16 • 9.1k RSET where VPIN16 = 0.048V typical. For single 5V supply operation, a 400Ω programming resistor is generally optimal. In applications that demand maximum amplifier linearity, or if external biasing is preferred (in DC-coupled applications, for example), the internal biasing circuitry may be disabled by leaving Pin 16 open. With Pin 16 open, input loading is approximately 200kΩ. Shutdown Control 2.5k IN 9.1k 6557 F01 Figure 1. Simplified Programmable Input Bias Circuit Diagram V+ 40k BIAS CIRCUITRY EN The LT6557 may be placed into a shutdown mode, where all three amplifier sections are deactivated and power supply draw is reduced to approximately 10µA. When the EN pin is left open, an internal 40k pull-up resistor brings the pin to V+ and the part enters the shutdown mode. Pulling the pin more than approximately 1.5V below V+ will enable the LT6557 (see Figure 2 for equivalent circuit). The pull-down current required to activate the part is typically 125µA. In most applications, the EN pin is simply connected to ground (for continuous operation) or driven directly by a CMOS-level logic gate (see Figure 3 for examples). Response time is typically 50ns for enabling, and 1µs for shutdown. In shutdown mode, the feedback resistors remain connected between the output pins and the individual ground (or V– connected) pins. Figure 2. Simplified Shutdown Circuit Diagram V+ V+ 1 LT6557 EN DISABLE 1 EN DISABLE LT6557 2 2 6557 F03 (3a) Open Drain or Open Collector (3b) CMOS Gate with Shared Supply Figure 3. Suitable Shutdown Pin Drive Circuits 6557fa 9 LT6557 SIMPLIFIED SCHEMATIC V+ EN BIAS OUT IN 500Ω 500Ω 6557 SS PACKAGE DESCRIPTION GN Package 16-Lead Plastic SSOP (Narrow .150 Inch) (Reference LTC DWG # 05-08-1641) .189 – .196* (4.801 – 4.978) .045 ±.005 16 15 14 13 12 11 10 9 .254 MIN .009 (0.229) REF .150 – .165 .229 – .244 (5.817 – 6.198) .0165 ± .0015 .150 – .157** (3.810 – 3.988) .0250 BSC RECOMMENDED SOLDER PAD LAYOUT 1 .015 ± .004 × 45° (0.38 ± 0.10) .007 – .0098 (0.178 – 0.249) .0532 – .0688 (1.35 – 1.75) 2 3 4 5 6 7 8 .004 – .0098 (0.102 – 0.249) 0° – 8° TYP .016 – .050 (0.406 – 1.270) NOTE: 1. CONTROLLING DIMENSION: INCHES INCHES 2. DIMENSIONS ARE IN (MILLIMETERS) .008 – .012 (0.203 – 0.305) TYP .0250 (0.635) BSC GN16 (SSOP) 0204 3. DRAWING NOT TO SCALE *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 6557fa 10 LT6557 PACKAGE DESCRIPTION DHC Package 16-Lead Plastic DFN (5mm × 3mm) (Reference LTC DWG # 05-08-1706) 0.65 ±0.05 3.50 ±0.05 1.65 ±0.05 2.20 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 4.40 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS R = 0.115 TYP 5.00 ±0.10 (2 SIDES) R = 0.20 TYP 3.00 ±0.10 (2 SIDES) 9 0.40 ± 0.10 16 1.65 ± 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) PIN 1 NOTCH (DHC16) DFN 1103 8 0.200 REF 1 0.25 ± 0.05 0.50 BSC 0.75 ±0.05 4.40 ±0.10 (2 SIDES) 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJED-1) IN JEDEC PACKAGE OUTLINE MO-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 6557fa Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 11 LT6557 TYPICAL APPLICATION Split Supply Operation with DC Bias Servo RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1399 300MHz Triple Current Feedback Amplifier 0.1dB Gain Flatness to 150MHz, Shutdown LT1675 250MHz Triple RGB Multiplexer 100MHz Pixel Switching, 1100V/µs Slew Rate, 16-Lead SSOP LT6550/LT6551 3.3V Triple and Quad Video Buffers 110MHz Gain of 2 Buffers in MS Package LT6553 650MHz Gain of 2 Triple Video Amplifier Optimized for Driving 75Ω Cables LT6554 650MHz Gain of 1 Triple Video Amplifier Performance Similar to the LT6553 with AV = 1, 16-Lead SSOP LT6555 650MHz Gain of 2 Triple Video Multiplexer Optimized for Driving 75Ω Cables LT6556 750MHz Gain of 1 Triple Video Multiplexer High Slew Rate 2100V/µs LT6558 550MHz, 2200V/µs Gain of 1 Triple Video Amplifier Single Supply with Input Bias Control 6557fa 12 Linear Technology Corporation LT/LWI 0606 • REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2006