AAT3103 AAT | Alldatasheet
Document overview
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Technical content
Features
- Source WLED Driver, up to 3 LEDs at up to 30mA, each
- Automatic Switching Between 1x and 2x Modes
- 900KHz Switching Frequency
- Linear LED Output Current Control ▪ Single-wire, S 2Cwire Interface AAT3103-1: 16-step AAT3103-2: 8-step ▪ ON/OFF or PWM Interface AAT3103-4
- ±10% LED Output Current Accuracy
- ±3% LED Output Current Matching
- Low-current Shutdown Mode
- Built-in Short Circuit and Thermal Protection
- Automatic Soft-start
- 2x2.1mm SC70JW-10 Package
Applications
- Cordless Phone Handsets
- Mobile Phone Handsets
- MP3 and PMP Players
- Digital Cameras Typical Application Input Voltage 2.7V to 5.5V EN/SET S2Cwire Interface IN EN/SET OUT D3RSET RSET 14.3kΩ COUT 1μF AGND WLEDs OSRAM LW M 678 or equivalent AAT3103-1CP 1μF CIN 1μF
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET AAT3103 3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET Pin Descriptions Pin # Symbol Description 1 D1 LED1 Current Source Output. Connect LED1’s anode to D1 and its cathode to AGND. 2 OUT Charge Pump Output. Bypass OUT to AGND with a 1 μF or larger ceramic capacitor. 3 C- Charge Pump Capacitor Negative Node. 4 C+ Charge Pump Capacitor Positive Node. Connect a 1 μF ceramic capacitor between C+ and C-. 5I N Power source input. Connect IN to the power source, typically the battery. Bypass IN to AGND with a 1μF or larger ceramic capacitor. EN/SET (AAT3103-1/-2) LED Enable and serial control input. EN/SET is the ON/OFF control for the LED and the S2Cwire digital input for the AAT3103-1/-2 to control the LED brightness up to the maximum current set by RSET. EN/PWM (AAT3103-4) LED ON/OFF and PWM (Pulse Width Modulation) control input. This logic input controls the LED outputs for the AAT3103-4. A PWM signal, ranging from 10% to 100% duty cycle, controls the LED current linearly between minimum and the full-scale output set by R SET.
7 RSET
A 1% tolerance resistor from this pin to AGND sets the maximum LED current value. For optimal LED output current accuracy and matching in the AAT3103-1/-2/-4, a 14.3kΩ resistor sets each full-scale output current to 20mA. 8 AGND Analog Ground. Connect this pin to the system’s analog ground plane. 9 D3 LED3 Current Source Output. Connect LED3’s anode to D3 and its cathode to AGND. 10 D2 LED2 Current Source Output. Connect LED2’s anode to D2 and its cathode to AGND. Pin Configuration SC70JW-10 (Top View) OUT AGND RSET IN EN/SET (EN/PWM) D1 1
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET AAT3103 3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET Absolute Maximum Ratings1 Symbol Description Value Units IN, C+, C-, OUT, D1, D2, D3, and RSET Pin Voltages to AGND -0.3 to 6.0 V EN/SET or EN/PWM Pin Voltage to AGND -0.3 to V IN + 0.3 V TJ Operating Junction Temperature Range -40 to 150 °C TLEAD Maximum Soldering Temperature (at leads, 10 sec) 300 °C Thermal Information Symbol Description Value Units PD Maximum Power Dissipation2, 3 625 mW ΘJA Maximum Thermal Resistance2 160 °C/W 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at co nditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Mounted on an FR4 circuit board. 3. Derate 6.25mW/°C above 40 °C ambient temperature.
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET AAT3103 3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET Electrical Characteristics1 IN = EN = 3.6V; C IN = 1μF; COUT = 1μF; CCP = 1μF; RSET = 14.3kΩ; TA=-40°C to 85°C unless otherwise noted. Typical values are at TA = 25°C. Symbol Description Conditions Min Typ Max Units Input Power Supply IN Input Voltage Range 2.7 5.5 V IIN Input Operating Current IN = 5.5V; EN = IN; VD1 = VD2 = VD3 = 0V 7.4 10 mAIN = 5.5V; EN = IN; ID1 = ID2 = ID3 = FS, excluding ID1-ID3; VD1 = VD2 = VD3 = IN – 1.5V 1.9 3 Operating, ID1 = ID2 = ID3 = OPEN 4 6.8 IIN(SHDN) Input Shutdown Current EN/SET or EN/PWM = GND 1 μA Charge Pump Section IOUT OUT Maximum Output Current 100 mA fOSC Charge Pump Oscillator Frequency 0.65 0.9 1.4 MHz VIN_(TH) Charge Pump Mode Hysteresis I D1 = ID2 = ID3 = 20mA 325 mV tOUT LED Output Current Start-up Time EN/SET or EN/PWM = IN 150 μs AAT3103-1/-2/-4: LED Current Source Outputs ID_(MAX) D1 - D3 Current Accuracy DATA = 1; V IN – VF = 1.5V. 18 20 22 mA ΔID_(MAX) D1 - D3 Current Matching DATA = 1; V IN – VF = 1.5V ±3 % ID_(DATA15) D1 - D3 Current Accuracy (AAT3103-1 only) DATA = 15; VIN – VF = 1.5V 1.0 1.34 1.61 mA ID_(DATA8) D1 - D3 Current Accuracy (AAT3103-2 only) DATA = 8; VIN – VF = 1.5V 1.0 1.34 1.61 mA ID_(10%) D1 - D3 Current Accuracy (AAT3103-4 only) DC = 10%; VIN – VF = 1.5V 2.5 mA VD_(TH) D1- D3 Charge Pump Mode Transition Threshold ID1 = ID2 = ID3 = 20mA 280 mV VSET RSET Pin Voltage 1.14 1.18 1.22 V AAT3103-1/-2: EN/SET and S2Cwire Control VENH EN/SET Input High Threshold Voltage 1.4 V VENL EN/SET Input Low Threshold Voltage 0.4 V IEN(LKG) EN/SET Input Leakage Current EN/SET = IN = 5V -1 1 μA tEN/SET(OFF) EN/SET Input OFF Timeout 500 μs tEN/SET(LAT) EN/SET Input Latch Timeout 500 μs tEN/SET(LOW) EN/SET Input Low Time 0.3 75 μs tENSET(H-MIN) EN/SET Minimum High Time 50 ns tENSET(H-MAX) EN/SET Maximum High Time 75 μs AAT3103-4: EN/PWM Current Control VENH EN/PWM Input High Threshold Voltage 1.4 V VENL EN/PWM Input Low Threshold Voltage 0.4 V IEN(LKG) EN/PWM Input Leakage Current EN/PWM = IN = 5V -1 1 μA tPWM(ON) PWM Control Turn-on Delay 110 μs tEN/PWM EN/PWM Input OFF Timeout 0.15 1 ms fPWM PWM Control Frequency Duty cycle = 80% 50 kHz 1. The AAT3103 is guaranteed to meet performance specifications over the -40°C to 85°C operating temperature range and is assured by design, characterization and correlation with statistical process controls.
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET AAT3103 3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET Typical Characteristics Shutdown Current vs. Temperature Temperature (°C) ISHDN (µA) 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 -40 -15 10 35 60 85 VIN = 5.5V VIN = 2.7V Operating Current vs. Input Voltage (VD1 = VD2 = VD3 = 0V) Input Voltage (V) IQ (mA) 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 2.5 3 3.5 4 4.5 5 5. -40°C 25°C 85°C Operating Current vs. Input Voltage (No Load; D1, D2, D3 Open) Input Voltage (V) IQ (mA) 3.6 3.8 3.9 4.1 4.2 2.5 3 3.5 4 4.5 5 5.5 85°C 25°C -40°C LED Current Matching vs. Temperature Temperature (°C) Current (mA) 19.0 19.5 20.0 20.5 21.0 -40 -15 10 35 60 85 Efficiency vs. Input Voltage Input Voltage (V) Efficiency (%) 100 ILED = 30mA,VF = 3.5V ILED = 20mA,VF = 3.2V ILED = 10mA,VF = 3.0V ILED Full Scale vs. RSET RSET (kΩ) ILED (mA) 8 1 3 1 8 2 32 83 3
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET AAT3103 3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET Typical Characteristics EN Input High Threshold Voltage vs. Input Voltage Input Voltage (V) VENH (V) 0.2 0.4 0.6 0.8 1.0 1.2 -40°C 25°C 85°C EN Input Low Threshold Voltage vs. Input Voltage Input Voltage (V) VENL (V) 0.2 0.4 0.6 0.8 1.0 1.2 -40°C 25°C 85°C EN/SET Input Latch Timeout vs. Input Voltage Input Voltage (V) tEN/SET(LAT) (V) 100 150 200 250 300 350 85°C 25°C -40°C EN/SET Input Off Timeout vs. Input Voltage Input Voltage (V) tEN/SET(OFF) (V) 100 150 200 250 300 350 400 85°C 25°C -40°C Turn-On to 2X Mode (VIN = 3.6V; 20mA/Dx) Time (200µs/div) EN/SET (2V/div) VOUT (5V/div) IIN (200mA/div) VD1 (2V/div) 4.2V 2.7V 3.2V Turn-Off from 2X Mode (VIN = 3.6V; 20mA/Dx) Time (100µs/div) EN/SET (2V/div) IIN (200mA/div) VD1 (2V/div)
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET AAT3103 3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET Typical Characteristics Turn-On to 1X Mode (VIN = 4.2V; 20mA/Dx) Time (200µs/div) EN/SET (2V/div) VOUT (2V/div) IIN (200mA/div) VD1 (2V/div) Output Ripple Waveform (2X Mode; 20mA/Dx) Time (1µs/div) VOUT (AC) (20mV/div) VD1 (20mV/div) VIN (20mV/div) LED Current Transition (VIN = 4.2V; 1.3mA to 20mA) Time (100µs/div) EN/SET (2V/div) VOUT (2V/div) IIN (50mA/div) VD1 (2V/div) 4.2V 2.7V 3.2V LED Current Transition (VIN = 4.2V; 20mA to 1.3mA) Time (100µs/div) EN/SET (2V/div) VOUT (2V/div) IIN (50mA/div) VD1 (2V/div) 4.2V 3.2V 2.7V Input Current vs. Input Voltage Input Voltage (V) Input Current (mA) 100 150 200 250 ILED = 30mA ILED = 20mA ILED = 10mA VIN Rising VIN Falling
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET AAT3103 3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET Functional Description The AAT3103 is a low-cost charge-pump solution designed to drive up to three WLEDs. The charge pump operates from a 2.7V to 5.5V power source and converts it to volt- age levels necessary to drive the LEDs. LED current is individually controlled through integrated current sourc- es powered from the output of the charge pump. Low 1x charge-pump output resistance and low-drop voltage current sources allow the charge pump to stay in 1x mode with an input voltage as low as 3.75V and LED forward voltages as high as 3.2V with 20mA LED current. Once in 2x mode, the charge pump monitors the input supply voltage and automatically switches back to 1x mode when there is sufficient input voltage. The AAT3103 requires only four external components: one 1 μF ceramic capacitor for the charge pump flying capacitors (C P), one 1 μF ceramic input capacitor (C IN), one 1 μF ceramic output capacitor (C OUT) and a resistor (RSET) to set the maximum LED current. The three con- stant current outputs of the AAT3103 (D1 to D3) can drive three individual LEDs with a maximum current of 30mA each. AnalogicTech’s S 2Cwire serial interface enables the AAT3103-1/-2 and changes the current source magnitudes through the EN/SET pin. The AAT3103-4 uses an external PWM signal to enable the IC and control the brightness of the LEDs. Constant Current Control Using RSET The maximum current is programmed by an external resistor at the RSET pin. With a 14.3kΩ external resistor at the RSET pin, the AAT3103 includes an integrated serial LED current control that sets the full-scale LED current between 20mA and 0.67mA. The full-scale LED current can be set higher or lower than 20mA; see Table 4. For maximum accuracy, a 1% tolerance resistor is recommended. Functional Block Diagram C–C+ OUT AGND IN S2Cwire Control (PWM Control) DACEN/SET (EN/ PWM) RSET Two-Mode CP Control VF Monitoring IREF
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET Applications Information LED Selection The AAT3103 is specifically intended for driving WLEDs. However, the device design will allow the AAT3103 to drive most types of LEDs with forward voltage specifica- tions ranging from 2.2V to 4.7V. LED applications may include mixed arrangements for display backlighting, keypad display, and any other application needing a con- stant current sink generated from a varying input volt- age. Since the D1 to D3 constant current sources are matched with negligible supply voltage dependence, the constant current channels will be matched regardless of the specific LED forward voltage (V F) levels. The internal charge pump and low dropout current sources in the AAT3103 maximize performance and make it capable of driving LEDs with high forward volt- ages. Multiple channels can be combined to obtain a higher LED drive current without complication. Constant Current Setting The LED full scale current is controlled by the R SET resis- tor. The following formula can be used to calculate the AAT3103-1/2/4 full scale LED current: ILED_FS = · 4 · 601.2 RSET Table 4 shows the RSET resistor value for the AAT3103-1/2/4 for various LED full-scale current levels. For maximum accuracy, a 1% tolerance resistor is recommended. ILED_FS (mA) R SET (kΩ) 30.2 9.53 20.1 14.3 15.1 19.1 10.0 28.7 Table 4: Maximum LED Current and R SET Resistor Values (1% Resistor Tolerance) for the AAT3103. The S2C interface rising edges control the LED current from full scale to the LSB. For the AAT3103-1, 16 steps are employed. Figure 5 shows the LED current of the AAT3103-1 at different R SET values. S2C Wire Interface Data Code Dx LED Current (mA) 1234567 89 1 0 1 1 1 2 1 3 1 4 1 5 1 6 RSET = 9.53k RSET = 14.3k RSET = 19.1k RSET = 28.7k Figure 5: AAT3103-1 LED Current Control Profile at Different RSET Values. Use the following formula to calculate the AAT3103-3 full scale LED current: ILED_FS = · 4 · 481.2 RSET For example, an 11.5k Ω 1% resistor is used to achieve 20mA full scale LED current operation. Device Switching Noise Performance The AAT3103 operates at a fixed frequency of approxi- mately 0.9MHz to control noise and limit harmonics that can interfere with the RF operation of mobile communi- cation devices. Back-injected noise appearing on the input pin of the charge pump is 20mV peak-to-peak, typically ten times less than inductor-based DC/DC boost converter WLED backlight solutions. The AAT3103's soft- start feature prevents noise transient effects associated with inrush currents during start-up of the charge pump circuit. Shutdown To activate the shutdown operation, the EN/SET input for the AAT3103-1/-2 should be pulsed low for longer than t OFF (500 μs). For the 3103-4 PWM options, shutdown operation is enabled when the EN/PWM input is pulsed low longer than 500 μs. In this state, the AAT3103 typi- cally draws less than 1 μA from the input. Registers are reset to 0 in shutdown.
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET Power Efficiency and Device Evaluation The charge pump efficiency discussion in the following sections accounts only for efficiency of the charge pump section itself. Due to the unique circuit architecture and design of the AAT3103, it is very difficult to measure efficiency in terms of a percent value comparing input power over output power. Since the AAT3103 outputs are pure constant current sources and typically drive individual loads, it is difficult to measure the output voltage for a given output pin to derive an overall output power measurement. For any given application, WLED forward voltage levels can dif- fer, yet the output drive current will be maintained as a constant. This makes quantifying output power a difficult task when taken in the context of comparing to other WLED driver circuit topologies. A better way to quantify total device efficiency is to observe the total input power to the device for a given LED current drive level. The best WLED driver for a given application should be based on trade-offs of size, external component count, reliability, operating range, and total energy usage... not just % efficiency. The AAT3103 efficiency may be quantified under very specific conditions and is dependent upon the input volt- age versus the outputs of D1, D2 and D3 for a given constant current setting. Depending on the combination of V IN and voltages sensed at the current sources, the device will operate in load switch mode. When any one of the voltages sensed at the current sources nears drop- out, the device will operate in 2x charge pump mode. Each of these modes will yield different efficiency values. Refer to the following two sections for explanations for each operational mode. 1x Mode Efficiency The AAT3103 1x mode is operational at all times and functions alone to enhance device power conversion effi- ciency when V IN is higher than the voltage across the load. When in 1x mode, voltage conversion efficiency is defined as output power divided by input power. η = PF PIN The ideal efficiency (η) in 1x charge-pump mode can be expressed as: POUT PIN VF · ILED VIN · IIN VF · ILED VIN · IOUT VF VIN η = = = ≈ -or- VF VIN η (%) = · 100 For a charge pump LED driver with V F of 3.2V and 4.2V input voltage, the theoretical efficiency is 76%. Due to internal switching losses and IC quiescent current con- sumption, the actual efficiency can be measured at 73%. 2x Charge Pump Mode Efficiency The AAT3103 contains a charge pump which will boost the input supply voltage in the event where V IN is less than the voltage required to supply the output. The effi- ciency ( η) can be simply defined as a linear voltage regulator with an effective output voltage that is equal to one half of the input voltage. Efficiency ( η) for an ideal 2x charge pump can typically be expressed as the output power divided by the input power. η = PF PIN In addition, with an ideal 2x charge pump, the output current may be expressed as 1/3 of the input current. The expression to define the ideal efficiency ( η) can be rewritten as POUT PIN VF · ILED VIN · IIN VF · ILED VIN · 2 · IOUT VF 2 · VIN η = = = ≈ -or- VF 2 · VIN η (%) = · 100 For a charge pump LED current source driver with V F of 3.2V and 2.7V input voltage, the theoretical efficiency is 59%. Due to internal switching losses and IC quiescent current consumption, the actual efficiency can be mea- sured at 57%. Efficiency will decrease substantially as load current drops below 1mA or when the voltage level at V IN approaches the voltage level at V OUT.
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET Evaluation Board Schematic AAT3103-1 1μF D11 D2 10 OUT C-3 5 IN AGND RSET EN/SET VCC JP1 123 DC+DC- C 10μF PIC12F675 VDD GP52
3 GP4
330Ω LED2 Red 330Ω LED1 Green CYCLE DOWN UP AAT3103-1 White LED Driver S2Cwire Microcontroller 1μF 1μF JP2 JP3 JP4 D1D2D3 14.3k SW VOUT SHDN GND VIN FB AAT1217-3.3 4.7μH 4.7μF R8 10k 4.7μF JP5 20k VR1 POT10K 0.1μF Figure 8: AAT3103 Evaluation Board Schematic.
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET AAT3103 3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET Evaluation Board Layout Figure 9: AAT3103 Evaluation Board Figure 10: AAT3103 Evaluation Board Component Side PCB Layout. Solder Side PCB Layout.
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET AAT3103 3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET
Ordering Information
Package Interface Current Control, Inverting Marking 1 Part Number (Tape and Reel)2 SC70JW-10 S 2Cwire 16-step 1DXYY AAT3103IJQ-1-T1 SC70JW-10 S 2Cwire 8-step AAT3103IJQ-2-T1 SC70JW-10 PWM Linear 2TXYY AAT3103IJQ-4-T1 All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/about/quality.aspx.
Package Information
0.45 ± 0.10 0.05 ± 0.05 2.10 ± 0.30 4° ± 4° 0.15 ± 0.05 2.00 ± 0.20 7° ± 3° 0.85 ± 0.15
1.10 MAX
0.100 0.225 ± 0.075 1.75 ± 0.10 2.20 ± 0.20
0.40 BSC
All dimensions in millimeters. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD.
3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET AAT3103 3-Channel Charge-Pump LED DriverChargePump TM PRODUCT DATASHEET Advanced Analogic Technologies, Inc.
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Phone (408) 737-4600 Fax (408) 737-4611 © Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech pr oduct. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifi cations or to discontinue any product or service without notice. Except as provided in AnalogicTech’s terms and conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties relating to fi tness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specifi c testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders.