BAT54

MIC2141 MICREL | Alldatasheet

Document overview

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Technical content

Features

• Implements low-power boost, SEPIC, or flyback
• 2.5V to 14V input voltage
• 330kHz switching frequency
• < 2µA shutdown current
• 7 0µA quiescent current
• 1.24V bandgap reference
• typical output current 1mA to 10mA
• SOT-23-5 Package

Applications

• LCD bias supply
• CCD digital camera supply

Ordering Information

Part Number Junction Temp. Range Package MIC2141-BM5 –40 °C to +85°C SOT-23-5 Typical Application MIC2141 Variable VOUTVC * (from DAC) 10µF 10µH 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0 5 10 15 20 25 VC (V) VOUT (V) Control Voltage vs. Output Voltage DAC-Controlled LCD Bias Voltage Supply

SOT-23-5 (BM) Pin Description Pin Number Pin Name Pin Function 1 IN Input: +2.5V to +14V supply for internal circuity. 2 GND Ground: Return for internal circuitry and internal MOSFET (switch) source. 3 SW Switch Node (Input): Internal MOSFET drain; 22V maximum. 4 FB Feedback (Input): Output voltage sense node. Compared to V C control input voltage. 5 VC Control (Input): Output voltage control signal input. Input voltage of 0.8V to 3.6V is proportional to 4.8V to 22V output voltage (gain of 6). If the pin is not connected, the output voltage will be VIN – 0.5V.

Absolute Maximum Ratings (Note 1) Control Input Voltage (VC ), Note 3 ..VIN–200mV ≤ VC ≤ 4V Operating Ratings (Note 2) Package Thermal Resistance

Electrical Characteristics

VIN = 3.6V, VOUT = 5V; IOUT = 1mA; TJ = 25°C, bold values indicate –40°C ≤ TA ≤ +85°C; unless noted. Parameter Condition Min Typ Max Units Input Voltage 2.5 14 V Quiescent Current Switch off, V IN = 3.6V 70 100 µA Comparator Hysteresis 10 mV Control Voltage Gain (VOUT /VC ) 2.5V ≤ VIN ≤ 12V, VOUT = 15V 6 Load Regulation 100 µA ≤ IOUT ≤ 1mA, VOUT = 15V 0.25 1 % Line Regulation 2.5V ≤ VIN ≤ 12V; IOUT ≤ 1mA 0.05 0.2 %/V Switch On-Resistance I SW = 100mA, VIN = 3.6V 4 Ω ISW = 100mA, VIN = 12V 2.5 Ω Oscillator Frequency 300 330 360 kHz Oscillator Duty Cycle 15 18 % Note 1. Exceeding the absolute maximum rating may damage the device. Note 2. The device is not guaranteed to function outside its operating rating. Note 3. V C = 4V sets VOUT to 24V (absolute maximum level on VSW ); VC must be ≤ VIN – 200mV.

FEEDBACK CURRENT ( µA) OUTPUT VOLTAGE (V) Feedback Current vs. Output Voltage 01234 OUTPUT VOLTAGE (V) CONTROL VOLTAGE (V) Control Voltage vs. Output Voltage VIN = 5V L = 33µH VIN = 3.6V VIN = 2.5V 5.7 5.8 5.9 6.0 6.1 6.2 6.3 6.4 0 5 10 15 20 25 GAIN OUTPUT VOLTAGE (V) Gain vs. Output Voltage VIN = 5V L = 33µH 01234 CONTROL CURRENT (nA) CONTROL VOLTAGE (V) Control Current vs. Control Voltage 14.80 14.85 14.90 14.95 15.00 012345 OUTPUT VOLTAGE (V) LOAD CURRENT (mA) Load Regulation VIN = 5V IPEAK = 100mA L = 33µH IPEAK = 150mA L = 22µH 14.0 14.2 14.4 14.6 14.8 15.0 2468 1 0 1 2 OUTPUT VOLTAGE (V) INPUT VOLTAGE (V) Line Regulation L = 33µH IL = 100µA 300 320 340 360 380 400 2 4 6 8 1 01 21 41 6 FREQUENCY (kHz) INPUT VOLTAGE (V) Oscillator Frequency vs. Input Voltage 120 160 200 240 280 02468 1 0 1 2 1 4 1 6 QUIESCENT CURRENT ( µA) INPUT VOLTAGE (V) Quiescent Current vs. Input Voltage 0.50 0.52 0.54 0.56 0.58 0.60 -40 -20 0 20 40 60 80 100 ON-TIME (µs) TEMPERATURE ( °C) On-Time vs. Temperature 300 310 320 330 340 350 -40 -20 0 20 40 60 80 100 FREQUENCY (kHz) TEMPERATURE ( °C) Frequency vs. Temperature -40 -20 0 20 40 60 80 100 DUTY CYCLE (%) TEMPERATURE ( °C) Duty Cycle vs. Temperature

14.00 14.20 14.40 14.60 14.80 15.00 -40 -20 0 20 40 60 80 100 OUTPUT VOLTAGE (V) TEMPERATURE ( °C) Output Voltage vs. Temperature VIN = 5V L = 33µH 2468 1 0 1 2 RIPPLE VOLTAGE (mV) INPUT VOLTAGE (V) Ripple Voltage vs. Input Voltage VOUT = 15V IL = 1mA L = 100µH 100 01234 EFFICIENCY (%) OUTPUT CURRENT (mA) Efficiency BAT54HT1 Diode 1N4148 Diode VIN = 5V VOUT = 15V L = 33µH 2 4 6 8 10 12 14 ON-RESISTANCE ( Ω ) INPUT VOLTAGE (V) On-Resistance vs. Input Voltage 100 200 300 400 500 600 700 800 900 2 4 6 8 10 12 14 VDS (mV) INPUT VOLTAGE (V) Switch Voltage Drop vs. Input Voltage IDS = 100mA -40 -20 0 20 40 60 80 100 R DS(on) (Ω ) TEMPERATURE ( °C) Switch On-Resistance vs. Temperature VIN = 3.3V 100 200 300 400 500 600 700 800 -40 -20 0 20 40 60 80 100 VDS (mV) TEMPERATURE ( °C) Switch Voltage Drop vs. Temperature VIN = 3.3V ID = 100mA -40 -20 0 20 40 60 80 100 QUIESCENT CURRENT ( µA) TEMPERATURE ( °C) Quiescent Current vs. Temperature VIN = 5V 5.90 5.92 5.94 5.96 5.98 6.00 -40 -20 0 20 40 60 80 100 GAIN TEMPERATURE ( °C) Gain vs. Temperature VIN = 5V

See “Applications Information” for component selection and predesigned circuits. Overview This MIC2141 is a fixed-duty-cycle, constant-frequency, gated- oscillator, micropower, switch-mode power supply controller. Quiescent current for the MIC2141 is only 70µA in the switch off state, and since a MOSFET output switch is used, addi- tional current needed for switch drive is minimized. Efficien- cies above 85% throughout most operating conditions can be realized. Regulaton Regulation is performed by a hysteretic comparator which regulates the output voltage by gating the internal oscillator. The user applies a programming voltage to the VC pin. (For a fixed or adjustable output regulator, with an internal refer- ence, use the MIC2142.) The output voltage is divided down internally and then compared to the V C , the control input voltage, forcing the output voltage to 6 times the VC . The comparator has hysteresis built into it, which determines the amount of low frequency ripple that will be present on the output. Once the feedback input to the comparator exceeds the control voltage by 10mV, the high-frequency oscillator drive is removed from the output switch. As the feedback input to the comparator returns to the control voltage level, the comparator is reset and the high-frequency oscillator is again gated to the output switch. Typically 10mV of hysteresis seen at the comparator will correspond to 60mV of low- frequency ripple at the output. Applications, which require continuous adjustment of the output voltage, can do so by adjustment of the VC control pin. Output The maximum output voltage is limited by the voltage capa- bility of the output switch. Output voltages up to 22V can be achieved with a standard boost circuit. Higher output volt- ages require a flyback configuration. Output Voltage Control The internal hysteretic comparator disables the output drive once the output voltage exceeds the nominal by 30mV. The drive is then enabled once the output voltage drops below the nominal by 30mV. The reference level, which actually programs the output voltage, is set by the VC control input. The output is 6 times the control voltage (V C ) and the output ripple will be 6 times the comparator hystersis. Therefore, with 10mV of hystersis, there will be ±30mV variation in the output around the nominal value. See the “Typical Characteristics: Control Voltage vs. Output Voltage” for a graph of input-to-output behavior. The common-mode range of the comparator requires that the maximum control voltage (V C ) be held to 200mV less than VIN. When programming for a 20V output, a minimum VIN of 3.5V will be required. See the “Typical Characteristics: Gain vs. Output Voltage” for a graph of gain behavior. To achieve 20V output at lower input voltages, the external resistive divider (R1 and R2) shown in Figure 2 can be added. This circuit will increase the control-to-output gain, while limiting the error introduced by the tolerance of the internal resistor feedback network.

Application Information

Predesigned circuit information is at the end of this section. Component Selection Boost Inductor Maximum power is delivered to the load when the oscillator is gated on 100% of the time. Total output power and circuit efficiency must be considered when determining the maxi- mum inductor. The largest inductor possible is preferable in order to minimize the peak current and output ripple. Effi- ciency can vary from 80% to 90% depending upon input voltage, output voltage, load current, inductor, and output diode. Equation 1 solves for the output current capability for a given inductor value and expected efficiency. Figures 5 through 9 graph estimates for maximum output current, assuming the minimum duty cycle, maximum frequency, and 85% effi- ciency. To determine the required inductance, find the inter- section between the output voltage and current and select the value of the inductor curve just above the intersection. If the efficiency is expected to be other than the 85% used for the graph, Equation 1 can then be used to better determine the maximum output capability. (1) I Vt 2L T V eff V O(max) IN(min)ON MAX S O IN min = () × − () The peak inductor and switch current can be calculated from Equation 2 or read from the graph in Figure 10. The peak current shown in Figure 10 is derived assuming a maximum duty cycle and a minimum frequency. The selected inductor and diode peak current capability must exceed this value. The peak current seen by the inductor is calculated at the maximum input voltage. A wider input voltage range will result in a higher worst-case peak current in the inductor. This effect can be seen in Table 4 by comparing the difference between the peak current at V IN(min) and VIN(max). (2) I tV LPK ON max IN max MIN = ()() DCM/CCM Boundary Equation 3 solves for the point at which the inductor current will transition from DCM (discontinuous conduction mode) to CCM (continuous conduction mode). As the input voltage is raised above this level the inductor has a potential for developing a dc component while the oscillator is gated on. Table 1 display the input points at which the inductor current can possibly operate in the CCM region. Operation in this region can result in a peak current slightly higher than displayed Table 4. (3) VV V 1 DIN ccm OUT FWD() =+() +−() Table 2 lists common inductors suitable for most applica- tions. Table 6 lists minimum inductor sizes versus input and output voltage. In low-cost, low-peak-current applications, RF-type leaded inductors may sufficient. All inductors listed in Table 4 can be found within the selection of CR32- or LQH4C-series inductors from either Sumida or muRata. rerutcafunaMs eireSe pyTeciveD ataRumC 4/C3/C1HQLt nuomecafrus adimuS2 3RCt nuomecafrus relliM.W.JF 87d edaellaixa tfarclioC0 9d edaellaixa Table 2. Inductor Examples evaluated at the maximum input voltage. Table 3. Diode Examples performance characteristics of various suitable diodes. Table 1. DCM/CCM Boundary

Figure 8. Inductor Selection for VIN = 9V

Figure 9. Inductor Selection for VIN = 12V

Figure 10. Peak Inductor Current vs. Input Voltage

Predesigned Circuit Values IPEAK IPEAK VIN(min) VIN(max) VOUT IOUT(max) L1 CR1 (V IN = VOUT – 0.5V) or 14V (VIN = VIN(min)) 2.5V 4.5V 5.0V 4mA 15 µH BAT54 230mA 128mA 3mA 18 µH BAT54 192mA 106mA 2mA 27 µH BAT54 128mA 71mA 1mA 56 µH BAT54 62mA 34mA 0.5mA 120 µH BAT54 29mA 16mA 5V bootstrap 14.8mA 3.9 µH MBR0503 890mA 500mA 2.5V 11.5V 12V 1mA 15 µH MBR0530 588mA 128mA 0.5mA 33 µH BAT54 267mA 58mA 0.2mA 82 µH BAT54 108mA 23mA 2.5V 4.7V 12V bootstrap 3.5mA 4.7 µH MBR0503 750mA 500mA 2.5V 4.7V 12V bootstrap 4.3mA 3.9 µH MBR0503 900mA 500mA 2.5V 14V 15V 0.8mA 15 µH MBR0530 741mA 128mA 0.5mA 27 µH MBR0530 412mA 71mA 0.2mA 68 µH BAT54 163mA 28mA 2.5V 14V 16V 0.8mA 15 µH MBR0530 710mA 128mA 0.5mA 22 µH MBR0530 456mA 87mA 0.2mA 56 µH BAT54 190mA 34mA 2.5V 14V 22V 0.5mA 15 µH MBR0530 590mA 128mA 0.2mA 39 µH BAT54 274mA 49mA 0.1mA 82 µH BAT54 130mA 23mA 3.0V 4.5V 5V 10mA 12 µH BAT54 288mA 190mA use for Li-ion 3.6mA 27 µH BAT54 128mA 85mA battery range 0.8mA 120 µH BAT54 29mA 19mA 5V bootstrap 20mA 4.7 µH MBR0530 730mA 450mA 3.0V 8.5V 9V 3mA 12 µH MBR0530 652mA 190mA use for Li-ion 1.7mA 22 µH MBR0530 296mA 103mA battery range 0.8mA 47 µH MBR0530 139mA 49mA 3.0V 4.7V 9V bootstrap 8mA 4.7 µH MBR0503 750mA 450mA use for Li-ion battery range 3.0V 11.5V 12V 2.1mA 12 µH MBR0530 882mA 190mA use for Li-ion 1.7mA 15 µH MBR0530 588mA 156mA battery range 1mA 27 µH MBR0530 327mA 85mA 0.45mA 56 µH BAT54 157mA 40mA 3.0V 4.7V 12V bootstrap 5.4mA 4.7 µH MBR0530 750mA 450mA use for Li-ion battery range 3.0V 14V 15V 1.6mA 12 µH MBR0530 926mA 190mA use for Li-ion 0.87mA 22 µH MBR0530 505mA 103mA battery range 0.41mA 47 µH BAT54 237mA 49mA 3.0V 4.7V 15V bootstrap 4mA 4.7 µH MBR0530 750mA 450mA use for Li-ion battery range 3.0V 14V 22V 1mA 10 µH MBR0530 1071mA 190mA use for Li-ion 0.8mA 15 µH MBR0530 714mA 152mA battery range 0.46mA 27 µH MBR0530 400mA 85mA 0.2mA 68 µH BAT54 157mA 3.3mA Table 4a. Typical Configurations for Wide-Range Inputs— 2.5V to 3.0V Minimum Input

VIN(min) VIN(max) VOUT IOUT(max) L1 CR1 (V IN = VOUT – 0.5V) (V IN = VIN(min)) 5.0V 8.5V 9V 17mA 8.2 µH MBR0530 795mA 467mA 15mA 10 µH MBR0530 652mA 383mA 10mA 12 µH MBR0530 643mA 319mA 5mA 27 µH BAT54 241mA 142mA 1mA 120 µH BAT54 54mA 32mA 5.0V 11.5V 12V 10mA 8.2 µH MBR0530 1,075mA 467mA 5mA 18 µH MBR0530 490mA 213mA 2mA 39 µH BAT54 226mA 98mA 1mA 82 µH BAT54 108mA 47mA 5.0V 14V 15V 7mA 8.2 µH MBR0530 1356mA 467mA 5mA 12 µH MBR0530 926mA 319mA 2mA 27 µH MBR0530 412mA 142mA 1mA 56 µH BAT54 199mA 68mA 5.0V 14V 16V 2.5mA 22 µH MBR0530 986mA 174mA 1mA 56 µH BAT54 190mA 68mA 0.5mA 120 µH BAT54 90mA 32mA 5.0V 14V 22V 1.7mA 22 µH MBR0530 486mA 174mA 1.0mA 39 µH BAT54 274mA 98mA 0.5mA 82 µH BAT54 130mA 47mA 0.1mA 180 µH BAT54 60mA 21mA 9.0V 11.5V 12V 33mA 15 µH MBR0530 588mA 460mA 20mA 22 µH MBR0530 401mA 314mA 10mA 47 µH BAT54 188mA 147mA 5mA 100 µH BAT54 88mA 69mA 1mA 470 µH BAT54 19mA 15mA 9.0V 14V 15V 20mA 15 µH MBR0530 741mA 460mA 10mA 27 µH MBR0530 412mA 256mA 5mA 56 µH BAT54 199mA 123mA 2mA 150 µH BAT54 74mA 46mA 1mA 270 µH BAT54 41mA 26mA 9.0V 14V 20V 4.5mA 39 µH BAT54 215mA 177mA 2mA 68 µH BAT54 131mA 84mA 1mA 150 µH BAT54 72mA 46mA 9.0V 14V 22V 4mA 39 µH BAT54 275mA 177mA 2mA 68 µH BAT54 157mA 101mA 1mA 150 µH BAT54 72mA 46mA 12V 14V 15V 45mA 18 µH MBR0530 618mA 511mA 20mA 39 µH BAT54 285mA 236mA 10mA 82 µH BAT54 136mA 112mA 5mA 150 µH BAT54 74mA 61mA 1.7mA 470 µH BAT54 24mA 20mA 12V 14V 20V 8mA 47 µH BAT54 230mA 196mA 5mA 68 µH BAT54 158mA 135mA 2mA 120 µH BAT54 90mA 77mA 1mA 390 µH BAT54 27mA 24mA 12V 21.5V 22V 7mA 47 µH BAT54 228mA 196mA 5mA 68 µH BAT54 157mA 135mA 2mA 150 µH BAT54 69mA 61mA 1mA 220 µH BAT54 47mA 42mA Table 4b. Typical Configurations for Wide-Range Inputs— 5V to 15V Minimum Input

Table 5. Typical Maximum Power Configuration for Regulated Inputs Table 6. Minimum Inductance Table 7. Component Supplier Websites

Package Information

0.20 (0.008) 0.09 (0.004) 0.60 (0.024) 0.10 (0.004) 3.02 (0.119) 2.80 (0.110) 10° 3.00 (0.118) 2.60 (0.102) 1.75 (0.069) 1.50 (0.059) 0.95 (0.037) REF 1.30 (0.051) 0.90 (0.035) 0.15 (0.006) 0.00 (0.000) DIMENSIONS: MM (INCH) 0.50 (0.020) 0.35 (0.014) 1.90 (0.075) REF SOT-23-5 (M) MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 2000 Micrel Incorporated