N3004

N3004 ETC

Document overview

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Technical content

5 Bit Programmable Synchronous

Buck Converter with Dual LDOs NIKO-SEM N3004 JAN-10-Y02 GENERAL DESCRIPTION The N3004 is a 5 bit TTL-compatible input, digital-to-analog (DAC) programmable, syn- chronous buck converter with dual LDOs controller designed specifically to power the Pentium ® II as well as the next generation of P6 family or other high performance core logic in desktop personal computer and file servers CPU applications. The N3004 switching section provides pro- grammability of output voltage from 1.3V to 2.05V in 50mV steps and 2.0V to 3.5V in 100 mV increments and the linear sections use external N-Channel power MOSFETs to provide fixed output voltages of 1.5V for GTL bus and 2.5V for clock. The N3004 monitors all the output voltages. A signal Power-Good signal is issued when the core is within ±15% of the DAC setting. Additional features are built-in over-voltage, over-current protections for the core output and logic compatible shutdown.

FEATURES

z Synchronous operation with high efficiency z TTL-compatible 5 bit DAC, output voltage selection from 1.3V to 3.5V programmable z Fast transient response z Provides 2 regulated voltages, 1.5V and 2.5V for linear section z Power-Good output voltage monitor z Over-Voltage and Over-Current protection z Logic level enable input z High performance and low cost solution

APPLICATIONS

z Powering Pentium, ® II, III or Deschutes, K6 and other advanced processor z High power DC to DC controller with triple output supplies TYPICAL APPLICATION N3004, Motherboard Power Regulation for Computers SECTION ENABLE POWER-GOOD VCORE VID 0~4 SECTION 12V 2.5V CLOCK SWITCHING LINEAR 3.3V 1.5V GTC BUS

Buck Converter with Dual LDOs NIKO-SEM N3004 JAN-10-Y02 ABSOLUTE MAXIMUM RATINGS PARAMETER VALUE Supply Voltage (V5 to GND) 10V Supply Voltage (V12 to GND) 20V Thermal Resistance Junction to Case, θJC 25°C/W Thermal Resistance Junction to Ambient, θJA 85°C/W Operating Temperature Range 0 to 70°C Storage Temperature Range -65 to +150°C Junction Operating Temperature 0 to +125°C Lead Temperature (Soldering, 10 Seconds) 300°C ELECTRICAL SPECIFICATIONS <Unless otherwise specified: V5 = 5V, V12 = 12V and TA = 25°C> PARAMETER CONDITIONS MIN TYP MAX UNITS SWITCHING SECTION DAC Output Voltage (Note 1) 0.99Vs Vs 1.01Vs V DAC Output Line Regulation 0.1 % DAC Output Temp. Variation 0.5 % VID Input LO 0.4 V VID Input HI 2 V VID Input Internal Pull-Up Resistor to V5 27 KΩ POWER GOOD SECTION Power Good Threshold Voltage 85 115 % Power Good Output LO I L = 3mA 0.4 V Power Good Output HI RL = 5KΩ pull up to 5V 4.8 V SOFT START SECTION Soft Star Current CS+ =0V, CS- =5V 10 μA UVLO SECTION UVLO Threshold for V12 Supply ramping up 9.2 10 10.8 V UVLO Hysterises for V12 0.3 0.4 .05 V UVLO Threshold for V5 Supply ramping up 4.1 4.3 4.5 V UVLO Hysterises for V5 0.2 0.3 0.4 V ERROR COMPARATOR SECTION Input Bias Current 2 μA Input Offset Voltage -2 +2 mV Delay to Output V DIFF = 10mV 100 nS

Buck Converter with Dual LDOs NIKO-SEM N3004 JAN-10-Y02 PARAMETER CONDITIONS MIN TYP MAX UNITS CURRENT LIMIT SECTION C.S Threshold Set Current 160 200 240 μA C.S Comparator Offset Voltage -5 +5 mV Hiccup Duty Cycle Css = 0.1μF 2 % SUPPLY CURRENT Operating Supply Current CL=3000 pF V5 20 V12 14 mA OUTPUT DRIVERS SECTION Rise Time C L = 3,000pF 60 100 nS Fall Time C L = 3,000pF 60 130 nS Dead Band Time C L = 3,000pF 100 200 300 nS OSCILLATOR SECTION Oscillator Frequency C L = 150pF 220 KHz Oscillator Valley 0.2 V Oscillator Peak V5 V LINEAR SECTIONS VFB1 & VFB2 1.40 1.50 1.60 V Input Bias Current 2 μA IDRIVER1 or IDRIVER2 50 mA Note 1: Vs refers to the set point voltage given in Table 1. PIN CONFIGURATIONS

Buck Converter with Dual LDOs NIKO-SEM N3004 JAN-10-Y02 PIN DEFINITIONS Pin # Pin Name Pin Function Description

1 C T The oscillator frequency is programmed by connecting an external cap-

acitor from this pin to GND. Operation in range of 50 KHz to 500 KHz. 2 L IN1 Gate drive output regulator, Linear 1 for GTL+ or Clock supply. 3 V FB1 Feedback input for L IN1. 4 V FB2 Feedback input for L IN2. 5 V5 5V supply voltage. 6 PGD * Open collector logic output, high if V O within 10% of set point.

7 CS- Current sense input (Negative), connected to the Source of the power

MOSFET for the core supply. CS+ Current sense input (Positive), connected to the Drain of the power MOS- FET for the core supply. An external resistor programs the C.S threshold depending on the R DS(ON) of the power MOSFET. An external capacitor is placed in parallel with the programming resistor to provide high frequency noise filtering. 9 H DRV High side driver output. GND This pin serves as the ground pin and must be connected directly to the ground plane. A high frequency capacitor (0.1 to 1μF) must be connected directly from V5 and V12 pins to this pin for noise free operation. 11 L DRV Low side driver output. V12 12V supply voltage for LINEAR section. A high frequency capacitor (0.1 to 1μF) must be connected directly from this pin to GND pin in order to supply the peak current to the power MOSFET during the transients. SS This pin provides the soft start for the switching regulator. An internal current source charges an external capacitor that is connected from this pin to the GND which ramps up the outputs of the switching regulator, preventing the outputs from overshooting as well as limiting the input current. The second function of the soft start cap is to provide long off time (HICCUP) for the synchronous MOSFET during current limiting. 14 V FB3 Feedback input for V CORE. 15 VID4 * Programming input (MSB). 16 VID3 * Programming input. 17 VID2 * Programming input. 18 VID1 * Programming input. 19 VID0 * Programming input (LSB). 20 L IN2 Gate drive output regulator, Linear 2 for GTL+ or Clock supply. * : All logic level inputs and outputs are open collector TTL compatible.

Buck Converter with Dual LDOs NIKO-SEM N3004 JAN-10-Y02 OUTPUT SET POINT VOLTAGE vs VID CODES − Table 1 − Vs VID4 VID3 VID2 VID1 VID0 1.30 0 1 1 1 1 1.35 0 1 1 1 0 1.40 0 1 1 0 1 1.45 0 1 1 0 0 1.50 0 1 0 1 1 1.55 0 1 0 1 0 1.60 0 1 0 0 1 1.65 0 1 0 0 0 1.70 0 0 1 1 1 1.75 0 0 1 1 0 1.80 0 0 1 0 1 1.85 0 0 1 0 0 1.90 0 0 0 1 1 1.95 0 0 0 1 0 2.00 0 0 0 0 1 2.05 0 0 0 0 0 2.00 1 1 1 1 1 2.10 1 1 1 1 0 2.20 1 1 1 0 1 2.30 1 1 1 0 0 2.40 1 1 0 1 1 2.50 1 1 0 1 0 2.60 1 1 0 0 1 2.70 1 1 0 0 0 2.80 1 0 1 1 1 2.90 1 0 1 1 0 3.00 1 0 1 0 1 3.10 1 0 1 0 0 3.20 1 0 0 1 1 3.30 1 0 0 1 0 3.40 1 0 0 0 1 3.50 1 0 0 0 0

Buck Converter with Dual LDOs NIKO-SEM N3004 JAN-10-Y02 APPLICATION CIRCUIT 3.3V 3.3V ++ ++ + + VID 0 VID 4 12V VID 1 VID 2 VID 3 P.G 100 VFB2 0.1uF 680uF VID 3 VFB1 10K VCORE VID 0 CS+ 150 2 uH HDRV 1uF 10K P50N02L x 2 1A/30V P3055LD x 2 100 220uF 1500uF x 5 VID 2 LIN2 100 PGD 1uF 2.5V CLOCK 0.1uF CS- 470pF 1000uF x 2 LDRV 100 1000uF SBD MOSFET10 N3004 CT GND 10K 680uF VID 4 VID 1 LIN1 0.01uF 1.5V GTC BUS 220pF 1uF VCC 2.21K Short or

5 OHM

0.1uF SS 150pF 100 2.5uH MOSFET 0.01uF V12

Buck Converter with Dual LDOs NIKO-SEM N3004 JAN-10-Y02 SOIC-20 (DW) MECHANICAL DATA mm mm A 12.6 13.0 H 0.4 1.27 B 7.3 7.7 I 0.23 0.32 C 10 10.65 J 0.25 0.74 D 0.33 0.51 K 0° 8° E 1.27 L F 2.1 2.3 2.5 M G 0.1 0.3 N