FAN5234 Fairchild Semiconductor, FAN5234 Datasheet
FAN5234
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FAN5234 Summary of contents
Page 1
... DS(ON) Feed-forward ramp modulation, average current mode control, and internal feedback compensation provide fast response to load transients. The FAN5234 monitors these outputs and generates a PGOOD (power-good) signal when the soft-start is completed and the output is within ±10% of its set point. A built-in over-voltage protection prevents the output voltage from going above 120% of the set point ...
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... VCC + ILIM SS1 FPWM 16 R4 AGND 8 PGOOD 2 Block Diagram © 2004 Fairchild Semiconductor Corporation FAN5234 • Rev. 2.0.0 VIN Q1A FA N5 234 HDRV Q1B LDRV 10 PGND 9 ISNS 12 VSEN 6 VOUT 5 Figure 1. 1.18V Output Regulator Figure 2 ...
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... MOSFET. 15 BOOT BOOT. Positive supply for the upper MOSFET driver. Connect as shown in Figure 2. Forced PWM Mode. When logic HIGH, inhibits the regulation from entering Hysteretic 16 FPWM Mode. © 2004 Fairchild Semiconductor Corporation FAN5234 • Rev. 2.0.0 VIN FPWM 1 16 PGOOD BOOT 2 15 ...
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... Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings. Symbol V V Supply Voltage Supply Voltage Ambient Temperature A Θ Thermal Resistance, Junction to Ambient JA © 2004 Fairchild Semiconductor Corporation FAN5234 • Rev. 2.0.0 Parameter Parameter Min. 4.75 4 Min. Max. 6 6.5 -0.3 V +0.3 CC -10 +150 -65 +150 +300 Typ ...
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... Under-Voltage Shutdown TSD I Over-Current Threshold SNS UVLO Over-Voltage Threshold Output Drivers HDRV Output Resistance LDRV Output Resistance © 2004 Fairchild Semiconductor Corporation FAN5234 • Rev. 2.0.0 Conditions Min. LDRV, HDRV Open; V Forced Above SEN Regulation Point Shutdown (EN-0) VIN Pin = Input Voltage 10 Source ...
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... PGOOD Output Low Leakage Current Soft-Start Voltage, PGOOD Enabled EN, FPWM Inputs V Input High INH V Input Low INL © 2004 Fairchild Semiconductor Corporation FAN5234 • Rev. 2.0.0 (Continued) Conditions % of Set Point, 2µs Noise Filter % of Set Point, 2µs Noise Filter I = 4mA PGOOD PULLUP 6 Min ...
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... Functional Description Overview The FAN5234 is a PWM controller intended for low- voltage power applications in notebook, desktop, and sub-notebook PCs. The output voltage of the controller can be set in the range of 0. external resistor divider. The synchronous buck converter can operate from an unregulated DC source (such as a notebook battery), with voltage ranging from 2V to 24V, or from a regulated system rail ...
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... ON ) ⎜ ⎟ = − R 100 ⎜ ⎟ SENSE μ 150 A ⎝ ⎠ © 2004 Fairchild Semiconductor Corporation FAN5234 • Rev. 2.0.0 PWMMode HystereticMode Setting the Current Limit A ratio of I established when a 0.9V internal reference drives the ILIM pin LIM ...
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... PWM control signal into the MOSFET gate drive signals, providing necessary amplification, level shifting, and shoot-through protection. It also has functions that help optimize the IC performance over a wide range of © 2004 Fairchild Semiconductor Corporation FAN5234 • Rev. 2.0 ISNS ...
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... If V drops below the under-voltage threshold, the OUT chip shuts down immediately. © 2004 Fairchild Semiconductor Corporation FAN5234 • Rev. 2.0.0 Over-Current Sensing If the circuit's current-limit signal (“I is HIGH at the beginning of a clock cycle, a pulse- skipping circuit is activated and HDRV is inhibited. The circuit continues to pulse skip in this manner for the next eight clock cycles ...
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... Power MOSFET Selection Losses in a MOSFET are the sum of its switching (P and conduction (P In typical applications, the FAN5234 converter's output (15) voltage is low with respect to its input voltage. Therefore, the lower MOSFET (Q2) is conducting the full-load current for most of the cycle. Q2 should ...
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... G(SW) (20) where Q MOSFET to its threshold (V For the high-side MOSFET, V high as 20V in a typical portable application. Care (21) should be taken to include the delivery of the MOSFET's gate power (P dissipation required for the FAN5234: (22 and ATE SW where Q Low-Side Losses Q2 switches on or off with its parallel Schottky diode conducting ...
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... It is not recommended to use high density interconnect systems, or micro-vias, on these signals. The use of blind or buried vias should be limited to the low-current signals only. The use of normal thermal vias is at the discretion of the designer. © 2004 Fairchild Semiconductor Corporation FAN5234 • Rev. 2.0.0 Qty. Ref. Vendor 1 C1 AVX ...
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... Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products. Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/. © 2004 Fairchild Semiconductor Corporation FAN5234 • Rev. 2.0.0 4.55 4.4±0.1 Figure 11. 16-Lead, Thin-Shrink Outline Package 14 5 ...
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... Fairchild Semiconductor Corporation FAN5234 • Rev. 2.0.0 15 www.fairchildsemi.com ...