MIC2178-3.3BWM TR Micrel Inc, MIC2178-3.3BWM TR Datasheet
MIC2178-3.3BWM TR
Specifications of MIC2178-3.3BWM TR
MIC2178-3.3BWMTR
Related parts for MIC2178-3.3BWM TR
MIC2178-3.3BWM TR Summary of contents
Page 1
... The output is protected with pulse-by-pulse current limiting and thermal shutdown. Undervoltage lockout turns the output off when the input voltage is less than 4.5V. The MIC2178 and is packaged in a 20-lead wide power SOIC package with an operating temperature range of –40°C to +85°C. ...
Page 2
... Pin Configuration Pin Description Pin Number Pin Name VIN PGND 10 PWM 11 PWRGD COMP 14, 15, 16, 17 SGND 18 SYNC 19 BIAS 20 EN M9999-031805 Part Number Pb-Free Voltage MIC2178YWM ADJ MIC2178-3.3YWM 3.3V MIC2178-5.0YWM 5.0V VIN 1 20 VIN PGND 4 17 PGND 5 16 PGND 6 15 PGND VIN ...
Page 3
... PWM mode, output not switching, 4.5V ≤ V ≤ 16.5V IN skip mode, output not switching, 4.5V ≤ V ≤ 16. 0V, 4.5V ≤ V ≤ 16. 16.5V IN MIC2178 [adj.]: V = 3.3V, I OUT MIC2178 [adj.]: V = 3.3V, OUT 5V ≤ V ≤ 16V, 10mA ≤ MIC2178-5. LOAD MIC2178-5.0: 6V ≤ V ≤ 16V, 10mA ≤ MIC2178-3 ...
Page 4
... PWRGD Threshold PWRGD Output Low PWRGD Off Leakage General Note: Devices are ESD sensitive. Handling precautions recommended. M9999-031805 Condition 5. 5.5V PWM MIC2178 [adj.]: measured at FB pin MIC2178-5.0: measured at FB pin MIC2178-3.3: measured at FB pin I = 1.0mA SINK V = 5.5V PWRGD 4 Micrel, Inc. Min ...
Page 5
... TEMPERATURE (°C) PWM-Mode Supply Current 12 OUTPUT 10 SWITCHING INPUT VOLTAGE (V) March 2005 Reference Voltage vs. Temperature 1.252 MIC2178 [adj.] 1.250 1.248 1.246 1.244 1.242 1.240 1.238 -60 - 120 150 TEMPERATURE (°C) Error-Amplifier Gain vs. Temperature 19.0 18.5 18.0 17.5 17.0 16.5 16.0 -60 -30 ...
Page 6
... Voltage PWM PWM/ Skip Mode Skip-Mode PWM Mode 10 Select Corrective Ramp SYNC 200kHz Stop Oscillator 18 Reset Pulse R C COMP MIC2178 [Adjustable] M9999-031805 Output I Control Logic I LIMIT Comp. I LIMIT Thresh. Voltage Skip-Mode Comp PWM Comp. V 1.245V REF SGND 14 ...
Page 7
... Shutdown Mode The MIC2178 has a low-current shutdown mode that is controlled by the enable input (EN). When a logic 0 is applied to EN, the MIC2178 is in shutdown mode, and its quiescent current drops to less than 5µA. Internal Bias Regulator An internal 3.3V regulator provides power to the MIC2178 control circuits. This internal supply is brought out to the BIAS pin for bypassing by an external 0.01µ ...
Page 8
... OUT multimedia circuits. There are two important items to be aware of when selecting PWM or skip mode. First, the MIC2178 can start-up only in PWM mode, and therefore requires a logic low at PWM during start-up. Second, in skip mode, the MIC2178 will supply a maximum load current of approximately 300mA, so the output will drop out of regulation when load current exceeds this limit ...
Page 9
... MIC2178 PWM-Mode Functional Diagram SYNC 200kHz Stop Oscillator 18 COMP MIC2178 [Adjustable] PWM-Mode Signal Path V SW Reset Pulse I LOAD I L1 Error Amp. Output I SENSE March 2005 Corrective Ramp Reset Pulse R Q PWM S Comp. Error Amp. V 1.245V REF SGND 4.5V to 16. VIN 100mΩ ...
Page 10
... MIC2178 Skip-Mode Functional Diagram Output Control Logic MIC2178 [Adjustable] Skip-Mode Signal Path OUT One-Shot Pulse I LIM 5mV REF – 5mV REF M9999-031805 4.5V to 16.5V VIN 100mΩ P-channel One Shot I SENSE Amp. I LIMIT Comp. I LIMIT Thresh. Voltage Skip-Mode Comp. V 1.245V REF ...
Page 11
... Application Information Feedback Resistor Selection (Adjustable Version) The output voltage is programmed by connecting an external resistive divider to the FB pin as shown in “MIC2178 Block Diagram.” The ratio determines the output voltage. To optimize efficiency during low output current operation, R2 should not be less than 20kΩ. However, to prevent feedback error due to input bias current at the FB pin, R2 should not be greater than 100kΩ ...
Page 12
... SGND should not be in the path of switching V IN 4.5V to 16.5V C1 22µF 35V R1 20k Skip Mode PWM Mode Figure 1. MIC2178 4.5V–16.5V to 3.3V/1A Regulator V IN 5.4V to 16.5V C1 22µF 35V R1 20k Skip Mode PWM Mode Figure 2. MIC2178 5.4V–16.5V to 5V/1A Regulator M9999-031805 currents returning to the power supply ground bus ...
Page 13
... R1 20k Skip Mode PWM Mode Figure 4. MIC2178 10V–16.5V to 3.3V/2.5A Regulator V IN 4.5V to 10V C1 22µF 35V R1 20k Skip Mode PWM Mode 6.8nF Figure 5. MIC2178 4.5V–10V to 3.3V/1A Regulator March 2005 1,2,9 L1 VIN 68µ PWRGD R2 MBRS130L 4–7 MIC2178 PGND 174k ...
Page 14
... MIC2178 Q1 SI9435 4.5V to 16. 22µF 35V Skip Mode PWM Mode Figure 6. MIC2178 Reversed Battery Protected Regulator 16.5V C1 22µF 35V R1 20k Skip Mode 10 PWM Mode 6.8nF U1 Micrel MIC2178-5.0BWM C1 AVX TPSE226M035R0300, ESR = 0.3Ω C2 AVX TPSD107M010R0100, ESR = 0.1Ω C3 AVX TPSD107M010R0100, ESR = 0.1Ω ...
Page 15
... MIC2178 Suggested Manufacturers List Inductors Capacitors Coilcraft AVX Corp. 1102 Silver Lake Rd. 801 17th Ave. South Cary, IL 60013 Myrtle Beach, SC 29577 tel: (708) 639-2361 tel: (803) 448-9411 fax: (708) 639-1469 fax: (803) 448-1943 Coiltronics Sanyo Video Components Corp. 6000 Park of Commerce Blvd. ...