MP2158_V01 MPS | Alldatasheet
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Technical content
MP2158 1A, 6V, 1.5MHz, 17μA IQ, COT Synchronous Step Down Switcher In Ultra-small 2x1.5mm QFN MP2158 Rev. 1.03 www.MonolithicPower.com 1 7/5/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. The Future of Analog IC Technology
DESCRIPTION
The MP2158 is a monolithic step-down switch mode converter with built-in internal power MOSFETs. It achieves 1A continuous output current from a 2.5V to 6V input voltage with excellent load and line regulation. The output voltage can be regulated as low as 0.6V. The Constant-On-Time control scheme provides fast transient response and eases loop stabilization. Fault condition protection includes cycle-by-cycle current limiting and thermal shutdown. The MP2158 is available in the small QFN8 2.0x1.5mm package and requires a minimum number of readily available standard external components. The MP2158 is ideal for a wide range of applications including High Performance DSPs, FPGAs, PDAs, and portable instruments.
FEATURES
Very Low I Q: 17μA Default 1.5MHz Switching Frequency EN and Power Good for Power Sequencing Ultra-small 2.0x1.5mm QFN8 Package Wide 2.5V to 6V Operating Input Range Output Adjustable from 0.6V Up to 1A Output Current 100% Duty Cycle in Dropout 118m Ω and 88mΩ Internal Power MOSFET Switches Cycle-by-Cycle Over Current Protection Short Circuit Protect with Hiccup Mode Stable with Low ESR Output Ceramic Capacitors
APPLICATIONS
Wireless/Networking Cards Portable Instruments Battery Powered Devices Low Voltage I/O System Power All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Products, Quality Assurance page. “MPS” and “The Future of Analog IC Technology” are registered trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION MP2158 FB VIN 10 F EN VIN 2.5V to 6V VOUT 1.2V/1A SW 10 F 200k 200k PG EN PG OUT 1 H AGND PGND
MP2158 – 1A, 6V, 1.5MHz SYNCHRONOUS STEP-DOWN SWITCHER MP2158 Rev. 1.03 www.MonolithicPower.com 2 7/5/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved.
ORDERING INFORMATION
Part Number* Package Top Marking MP2158GQH QFN-8 (2.0mmx1.5mm) See Below * For Tape & Reel, add suffix –Z (e.g. MP2158GQH–Z); TOP MARKING BE: product code of MP2158GQH; LL: lot number; PACKAGE REFERENCE TOP VIEW PG VIN SW PGND EN FB AGND OUT QFN-8 (2.0mmx1.5mm) ABSOLUTE MAXIMUM RATINGS (1) -0.3V (-1.5V for <20ns&-4V for <8ns) to 6.5V (10V for <10ns) Continuous Power Dissipation (TA = +25°C) (2) Recommended Operating Conditions (3) Operating Junction Temp. (TJ). -40°C to +125°C Thermal Resistance (4) θJA θJC Notes: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the maximum junction temperature T J (MAX), the junction-to- ambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by P D (MAX) = (T J (MAX)-TA)/θJA. Exceeding the maximum allowable powe r dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage. 3) The device is not guaranteed to function outside of its operating conditions. 4) Measured on JESD51-7, 4-layer PCB.
MP2158 – 1A, 6V, 1.5MHz SYNCHRONOUS STEP-DOWN SWITCHER MP2158 Rev. 1.03 www.MonolithicPower.com 3 7/5/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. ELECTRICAL CHARACTERISTICS (5) VIN = 5V, TA = +25C, unless otherwise noted. Parameter Symbol Condition Min Typ Max Units 2.5V ≤ VIN ≤ 6V -3% 0.600 +3%Feedback Voltage V FB V/% Feedback Current I FB V FB = 0.6V 10 50 nA PFET Switch On Resistance R DSON_P 118 m Ω NFET Switch On Resistance R DSON_N 88 m Ω Switch Leakage VEN = 0V, VIN = 6V VSW = 0V and 6V 0 1 μA PFET Current Limit 2 A VIN=5V, VOUT=1.2V 185 ON Time T ON VIN=3.6V, VOUT=1.2V 245 ns VOUT=1.2V -20% 1500 +20% kHz/%Switching frequency F s TA=-40oC to +85oC(6) -25% 1500 +25% kHz/% Minimum Off Time T MIN-OFF 60 ns Soft-Start Time T SS-ON 1.5 ms Power Good Upper Trip Threshold PG H FB voltage respect to the regulation +10 % Power Good Lower Trip Threshold PG L -10 % Power Good Delay PG D 50 μs Power Good Sink Current Capability VPG-L Sink 1mA 0.4 V Power Good Logic High Voltage V PG-H V IN=5V, VFB=0.6V 4.9 V Power Good Internal Pull Up Resistor RPG 550 k Ω Under Voltage Lockout Threshold Rising 2.15 2.3 2.45 V Under Voltage Lockout Threshold Hysteresis 260 mV EN Input Logic Low Voltage 0.4 V EN Input Logic High Voltage 1.2 V VEN=2V 1.5 μA EN Input Current VEN=0V 0 μA Supply Current (Shutdown) V EN=0V 0 1 μA Supply Current (Quiescent) V EN=2V, VFB=0.63V, VIN=5V 17 20 μA Thermal Shutdown(5) 150 C Thermal Hysteresis(5) 30 C Notes: 5) Guaranteed by design. 6) Guaranteed by characterization test.
MP2158 – 1A, 6V, 1.5MHz SYNCHRONOUS STEP-DOWN SWITCHER MP2158 Rev. 1.03 www.MonolithicPower.com 4 7/5/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. TYPICAL PERFORMANCE CHARACTERISTICS VIN = 5V, VOUT = 1.2V, L = 1.0µH, TA = +25ºC, unless otherwise noted.
MP2158 – 1A, 6V, 1.5MHz SYNCHRONOUS STEP-DOWN SWITCHER MP2158 Rev. 1.03 www.MonolithicPower.com 5 7/5/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 5V, VOUT = 1.2V, L = 1.0µH, TA = +25ºC, unless otherwise noted.
MP2158 – 1A, 6V, 1.5MHz SYNCHRONOUS STEP-DOWN SWITCHER MP2158 Rev. 1.03 www.MonolithicPower.com 6 7/5/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 5V, VOUT = 1.2V, L = 1.0µH, TA = +25ºC, unless otherwise noted
MP2158 – 1A, 6V, 1.5MHz SYNCHRONOUS STEP-DOWN SWITCHER MP2158 Rev. 1.03 www.MonolithicPower.com 7 7/5/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. PIN FUNCTIONS Pin # Name Description
1 EN On/Off Control
2 FB Feedback pin. An external resistor divider from the output to AGND, tapped to the FB pin, sets the output voltage.
3 AGND Analogy ground for internal control circuit
4 OUT Input sense pin for output voltage
5 PGND Power ground
6 SW Switch Output
7 VIN Supply Voltage. The MP2158 operates from a +2.5V to +6V unregulated input. C1 is needed to prevent large voltage spikes from appearing at the input. 8 PG Power Good Indicator. The output of this pin is an open drain with internal pull up resistor to VIN. PG is pulled up to VIN when the FB voltage is within ±10% of the regulation level, if FB voltage is out of that regulation range, it is LOW.
MP2158 – 1A, 6V, 1.5MHz SYNCHRONOUS STEP-DOWN SWITCHER MP2158 Rev. 1.03 www.MonolithicPower.com 8 7/5/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. BLOCK DIAGRAM Main Switch (PCH ) Synchronous Rectifier (N CH ) Constant On -Time Pulse PWM Bias Voltage Reference 0.6V EN FB SW COMP VIN FBCOMP EN Driver PDRV NDRV Soft start PGND AGND OUT PWM COMP COMP 0. 66V 0. 54V PG Hi-Z FB for Fixed Output VIN E.A. Ramp Generator COMP VOUT RST SW Lo-Iq Lo-Iq Lo-Iq Lo-Iq Lo-Iq VTH Figure 1: MP2158 Block Diagram
MP2158 – 1A, 6V, 1.5MHz SYNCHRONOUS STEP-DOWN SWITCHER MP2158 Rev. 1.03 www.MonolithicPower.com 9 7/5/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. OPERATION MP2158 uses constant on-time control with input voltage feed forward to stabilize the switching frequency over full input range. At light load, MP2158 employs a proprietary control of low side switch and inductor current to eliminate ringing on switching node and improve efficiency. Constant On-time Control Compare to fixed frequency PWM control, constant on-time control offers the advantage of simpler control loop and faster transient response. By using input voltage feed forward, MP2158 maintains a nearly constant switching frequency across input and output voltage range. The on- time of the switching pulse can be estimated as: OUT ON IN VT0 . 6 6 7 sV To prevent inductor current run away during load transient, MP2158 fixes the minimum off time to be 60ns. However, this minimum off time limit will not affect operation of MP2158 in steady state in any way. Light Load Operation In light load condition, MP2158 uses a proprietary control scheme to save power and improve efficiency. The MP2158 will turn off the low side switch when inductor current starts to reverse. Then MP2158 works in discontinuous conduction mode (DCM) operation. The DCM mode happens only after low side switch turned off by ZCD circuit. Considering the ZCD circuit propagation time, the typical delay is 30ns. It means the inductor current still fall after the ZCD is trigger during this delay. If the inductor current falling slew rate is fast (Vo voltage is high or close to Vin), the low side MOSFET is turned off at the moment inductor current may be negative. This phenomena will cause MP2158 can not enter DCM operation. If the DCM mode is required, the off time of low side MOSFET in CCM should be longer than 60ns. It means the maximum duty is 90% to guarantee DCM mode at light load. For example, V IN is 3.4V and V OUT is 3.3V, the off time in CCM is 20ns. It is difficult to enter DCM at light load. And using smaller inductor can improve it and make it enter DCM easily. Sleep/DCM Mode Transition MP2158 features sleep mode to get higher extreme light load efficiency. Operating in sleep mode, IC consumes ultra low quiescent current, typical 17uA here. At extreme light load condition, when internal error amplifier output (EAO) drop to sleep threshold and next pulse interval is longer than 4µs typically, IC enters into sleep mode to improve efficiency. Both EAO and pulse interval meet upper condition, IC works in sleep mode. In sleep mode, IC disables the most parts of internal control circuits to lower the quiescent current. At this time, Error amplifier will dominate the output voltage, FB voltage plus internal Ramp ripple compare with reference voltage. When FB voltage plus internal Ramp ripple drop to touch reference voltage, the IC wakes up previous disabled circuits and SW pulse happens. If the EAO and pulse interval meet the sleep condition, the IC will enter sleep mode again. Operating in sleep mode, average FB is above on the reference voltage, output voltage is a little higher than normal value. At the same time, pulse width in sleep mode is a little longer than normal SW on pulse, it because that wake up other control circuits need some delay time. Figure 2: Sleep Mode Control With load increasing, the output ripple is decreasing. The EAO ripple also decreases. Either EAO cannot reach sleep threshold or pulse interval is less than 4µs typically, IC quit sleep mode and works in DCM (Discontinue Control Mode). In DCM mode, all the internal control circuits work normally. Error amplifier and FBCOMP comparator will dominate the output voltage together. FB voltage plus internal Ramp ripple compare with EAO. And the EAO will self-adjust to get FB equal to REF. When FB voltage plus internal Ramp ripple drops to
MP2158 – 1A, 6V, 1.5MHz SYNCHRONOUS STEP-DOWN SWITCHER MP2158 Rev. 1.03 www.MonolithicPower.com 11 7/5/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved.
APPLICATION INFORMATION
Setting the Output Voltage The external resistor divider is used to set the output voltage (see Typical Application on page 1). The feedback resistor R1 can not be too large neither too small considering the trade-off for stability and dynamic. Choose R1 to be around 120kΩ to 200kΩ. R2 is then given by: out R1R2 V 10.6 The feedback circuit is shown as Figure 5. Vout FB MP2158 Figure 5: Feedback Network Table 1 lists the recommended resistors value for common output voltages. Table 1—Resistor Selection for Common Output Voltages VOUT (V) R1 (k Ω) R2 (k Ω) Selecting the Inductor A 0.68µH to 2.2µH inductor is recommended for most applications. For highest efficiency, the inductor DC resistance should be less than 15mΩ. For most designs, the inductance value can be derived from the following equation. OUT IN OUT IN L OSC V( V V )L VI f Where ΔIL is the inductor ripple current. Choose inductor current to be approximately 30% of the maximum load current. The maximum inductor peak current is: III L LOAD)MAX(L Selecting the Input Capacitor The input current to the step-down converter is discontinuous, therefore a capacitor is required to supply the AC current to the step-down converter while maintaining the DC input voltage. Use low ESR capacitors for the best performance. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. For most applications, a 10µF capacitor is sufficient. For higher output voltage, 47uF may be needed for more stable system. Since the input capacitor absorbs the input switching current it requires an adequate ripple current rating. The RMS current in the input capacitor can be estimated by: IN OUT IN OUTLOAD1C V V1V VII The worse case condition occurs at VIN = 2VOUT, where: II LOAD 1C For simplification, choose the input capacitor whose RMS current rating greater than half of the maximum load current. The input capacitor can be electrolytic, tantalum or ceramic. When using electrolytic or tantalum capacitors, a small and high quality ceramic capacitor, i.e. 0.1μF, should be placed as close to the IC as possible. When using ceramic capacitors, make sure that they have enough capacitance to provide sufficient charge to prevent excessive voltage ripple at input. The input voltage ripple caused by capacitance can be estimated by: LOAD OUT OUT IN INSI N IV VV1 fC 1V V
MP2158 – 1A, 6V, 1.5MHz SYNCHRONOUS STEP-DOWN SWITCHER MP2158 Rev. 1.03 www.MonolithicPower.com 13 7/5/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. TYPICAL APPLICATION CIRCUITS MP2158 FB VIN 10 F EN VIN 2.5V to 6V VOUT 1.2V/1A SW 10 F 200k 200k PG EN PG OUT 1 H AGND PGND Figure 6: Typical Application Circuit
MP2158 – 1A, 6V, 1.5MHz SYNCHRONOUS STEP-DOWN SWITCHER NOTICE: The information in this document is subject to change wi thout notice. Please contact M PS for current specifications. Users should warrant and guarantee that third party Intellectual Property rights ar e not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. MP2158 Rev. 1.03 www.MonolithicPower.com 14 7/5/2016 MPS Proprietary Information. Patent Protec ted. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved.
PACKAGE INFORMATION
QFN-8 (2.0mmX1.5mm) SIDE VIEW BOTTOM VIEW NOTE: 1) ALL DIMENSIONS ARE IN MILLIMETERS. 2) EXPOSED PADDLE SIZE DOES NOT INCLUDE MOLD FLASH. 3) LEAD COPLANARITY SHALL BE 0.10 MILLIMETERS MAX. 4) JEDEC REFERENCE IS MO-220. 5) DRAWING IS NOT TO SCALE. PIN 1 ID MARKING TOP VIEW PIN 1 ID INDEX AREA RECOMMENDED LAND PATTERN PIN 1 ID