1237SC

IRU1237SC IRF | Alldatasheet

Document overview

• Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
• PDF pages: 7

Technical content

1Rev. 1.2 07/14/03 www.irf.com PACKAGE ORDER INFORMATION

APPLICATIONS

DESCRIPTION

The IRU1237SC voltage regulator solution contains three integrated, fixed, linear voltage regulators in one 7-pin surface mount package. The first is a 2.6V regulator to power the read channel and integrated controller/mP. The second is a 3.3V regulator to power the controller I/O and memory chips requiring 3.3V. The last is an 8V regu- lator to power the preamp chip. The bandgap reference, the 8V ground, and the substrate are all tied to a com- mon ground pin, while the 2.6V and 3.3V ground is tied to a separate ground pin. This grounding scheme allows for improved noise isolation between the 8V regulator and the 2.6V and 3.3V regulators. The 2.6V and 3.3V regulators shall each be capable of 1.2A continuous for a 5.25V input. The 8V regulator shall be capable of 0.2A continuous for a 13.2V input. THREE INTEGRATED, FIXED OUTPUT LINEAR VOLTAGE REGULATORS Figure 1 - Typical application of IRU1237SC. Data Sheet No. PD94581

FEATURES

Stable with Ceramic Capacitor Fixed 8V, 3.3V and 2.6V Fast Transient Response Output Current Limiting for each outputs Built-In Thermal Shutdown Hard Disk Drive Multi-Outputs Applications High Efficiency Linear Regulator PRELIMINARY DATA SHEET TYPICAL APPLICATION TJ (°C) 7-PIN PLASTIC PACKAGE Ultra Thin-PakTM (P) MARKING

0 To 150 IRU1237SCCP US1237SCCP

2.6V / 1.2A 8V / 200mA 3.3V / 1.2A

2 Rev. 1.2 07/14/03 www.irf.com ABSOLUTE MAXIMUM RATINGS

PACKAGE INFORMATION

7-PIN ULTRA THIN-PAKTM (P) θJA=30°C/W for 1"sq pad Output Voltage #1 Output Voltage #1 Output Voltage #2 Output Voltage #2 Output Voltage #3 Line Regulation Load Regulation Dropout Voltage (Output #1) Dropout Voltage (Output #2) Dropout Voltage (Output #3) Transient Response Current Limit (Output #1) Current Limit (Output #2) Current Limit (Output #3) Min Load Current (Output #1) Min Load Current (Output #2) Min Load Current (Output #3) Output Capacitor Input Capacitor Thermal Regulation ELECTRICAL SPECIFICATIONS Unless otherwise specified, these specifications apply over V CC=5V, V DD=12V, CIN=COUT=0.1mF(X7R), TJ=0 to PARAMETER SYM TEST CONDITION MIN TYP MAX UNITS 2.522 2.20 3.20 2.90 7.76 1.50 1.50 0.25 0.1 0.1 2.60 2.60 3.30 3.30 8.00 0.2 0.4 1.3 1.1 2.0 1.0 1.65 1.65 0.30 0.1 2.678 2.65 3.40 3.40 8.24 1.7 1.3 2.2 2.50 2.50 0.50 0.3 V V V V V %Vo %Vo V V V ms A A A mA mA mA mF mF %/W Over all operating conditions 0V<VDD<10.8V, IO1=0.5A Over all operating conditions 0V<VDD<10.8V, IO1=0.5A Over all operating conditions IO=10mA, VCC65%, VDD610% Note 1, 10mA < IO < IFL Note 2, IO1=IFL1 Note 2, IO2=IFL2 Note 3, IO3=IFL3 Note 3 and 7 DVO1=125mV DVO2=165mV DVO3=400mV Note 4 and 7 Note 4 and 7 Note 4 and 7 Note 5 and 7 Note 7 Note 7, 30ms pulse, IO=IFL VO1 VO1 VO2 VO2 VO3 RegLINE RegLOAD VDO1 VDO2 VDO3 tTR IOL1 IOL2 IOL3 LO1(MIN) LO2(MAX) LO3(MAX) CO CIN RegTHERM Gnd26/33 V33 Vcc VDD V26 Gnd8

3Rev. 1.2 07/14/03 www.irf.com Ripple Rejection (VCC to Output #1) Ripple Rejection (VCC to Output #2) Ripple Rejection (VDD to Output #3) TJ Thermal Shutdown Temperature Stability Long Term Stability RMS Output Noise VCC Quiescent current VDD Quiescent current PARAMETER SYM TEST CONDITION MIN TYP MAX UNITS 150 0.5 0.3 0.003 dB dB dB %Vo %Vo %Vo mA mA Note 7, 100Hz<f<100KHz, IO=IFL1/10 Note 7, 100Hz<f<100KHz, IO=IFL2/10 Note 7, 100Hz<f<100KHz, IO=IFL3/10 Note 7 Note 6 and 7, IO=10mA Note 7, TJ=1258C, 1000Hrs Note 7, 10Hz<f<10KHz IO1=IO2=IO3=0 IO1=IO2=IO3=0 PSRR1 PSRR2 PSRR3 TTHERM StabTEMP StabLONG VN IQ1 IQ2 Note 1: Low duty cycle pulse testing with Kelvin con- nections is required in order to maintain accurate data. Note 2: Dropout voltage is defined as the minimum dif- ferential voltage between VIN and VOUT required to main- tain regulation at VOUT. It is measured when the output voltage drops 1% below its nominal value. Note 3: Transient response is defined with a step change in load from 10mA to IFL/2, as the time from the load step until the output voltage reaches its minimum value. Note 4: Minimum load current is defined as the mini- mum current required at the output in order for the out- put voltage to maintain regulation. Note 5: The regulator shall withstand 100,000 reverse bias discharges of the maximum output capacitance, with no degradation, when the input voltage is switched to ground in 1ms. Note 6: Temperature stability is the change in output from nominal over the operating temperature range. Note 7: Guaranteed by design, but not tested in produc- tion. PIN# PIN SYMBOL PIN DESCRIPTION Gnd26/33, Gnd8 V33 VCC VDD V26 These pins are connected to ground. It is also the tab of the device. Output #1. Fixed regulator output (3.3V). Positive unregulated supply input for the regulator. This pin must always be higher than both VOUT pins by the amount of the dropout voltage in order for the device to regulate properly. Bypass to ground with low ESR and ESL capacitance. Output #3. Fixed regulator output (8V). Input voltage to supply the base current for the pass transistor for both regulators. Output #2. Fixed regulator output (2.6V). PIN DESCRIPTIONS 1,4

4 Rev. 1.2 07/14/03 www.irf.com Figure 2 - Simplified block diagram of the IRU1237SC. BLOCK DIAGRAM Vcc VDD V33 V26 Gnd26/33 Thermal Shutdown Thermal Shutdown Pre-Driver Controller Pre-Driver Controller Thermal Shutdown Bandgap Gnd8

5Rev. 1.2 07/14/03 www.irf.com

APPLICATION INFORMATION

The IRU1237SC regulator is 7-pin terminal device and contains three integrated, fixed, linear regulators. The dual inputs provide a low dropout voltage for V33 and V26 by biasing the base current to power NPN transistors. The IRU1237SC is designed to meet the fast current transient needs as well as an accurate initial voltage, thus reducing the overall system cost with the need for fewer number of output capacitors. Thermal Protection The IRU1237SC provides thermal protection for all three outputs. All outputs will be disabled for any over-tem- perature condition. When one of the outputs exceeds the thermal limit (typically 1508C), the IRU1237SC shuts down all three outputs simultaneously. The outputs will be re-enabled when the temperature drops below the thermal limit. Current Limit Protection The IRU1237SC provides over current protection when one the outputs’ current exceeds the current limit level. Stability The IRU1237SC doesn’t require input and output capaci- tors for stability, however to improve the transient re- sponse and guarantee stability, it is recommended that a 0.1mF (minimum) ceramic for input and output capaci- tors be used. Transient Response and PSRR The input and output capacitors are critical in order to ensure good transient response and PSSR. The most important aspects of this are capacitor selection, place- ment, and trace routing. Place each capacitor as close as physically possible to it’s corresponding regulator pin. Use wide traces for low inductance path. Couple directly to the ground and power planes as possible. The use of low ESR capacitors is crucial to achieving good results. An input capacitance of at least 0.1mF is recommended. An output capacitance of at least 0.1mF with low ESR is recommended for good PSSR at high frequencies. Ce- ramic capacitors are a good choice for low ESR. Larger capacitance and lower ESR will improve both PSSR and transient response. VIN1=5.25V VIN2=12V IOUT1=0.5A IOUT2=0.5A IOUT3=0.1A VOUT1=2.6V VOUT2=3.3V VOUT3=8V RTH(JA)=30W/8C TA = 508C DT = PD3RTH(JA) = 2.7W330 = 818C TJ = TA+DT = 1318C PD = (V IN1 -VOUT1 )3 IOUT1 +(VIN1 -VOUT2 )3 IOUT2 +(VIN2 - VOUT3)3IOUT3 PD = 2.7W Thermal Design The IRU1237SC incorporates an internal thermal shut- down that protects the device when the junction tem- perature exceeds the allowable maximum junction tem- perature. Although this device can operate with junction temperatures in the range of 1508C, it is recommended that the selected heat sink be chosen such that during maximum continuous load operation the junction tem- perature is kept below this number. The following thermal design illustrates the method used to calculate the maximum junction temperature of the regulator. Calculating the maximum power dissipation: For Ultra Thin-PakTM we have: Layout Consideration The IRU1237SC, like many other high-speed regulators, requires that the output capacitors be close to the de- vice for stability. For power consideration, a ground plane pad of approximately one-inch square on the compo- nent side must be dedicated to device where all ground pins are connected to dissipate the power. The copper area under the package shall have vias to the internal ground plane. The thermal ground plane shall extend out from the regulator to open areas of the PCB. All open areas shall be filled with copper to help radiate heat from the PCB.

6 Rev. 1.2 07/14/03 www.irf.com (P) Ultra Thin-PakTM 7-Pin NOTE: ALL MEASUREMENTS ARE IN MILLIMETERS. SYMBOL A B C D E G H K L M N P R U V MIN 9.27 8.89 7.87 1.78 0.63 10.41 0.76 0.03 0.89 0.79 MAX 9.52 9.14 8.13 2.03 0.79 10.67 1.27 0.13 1.14 1.04

0.25 NOM

1.27 0.25

5.59 NOM

7.49 NOM

A E M L N U C B K P V H G D R LC

7Rev. 1.2 07/14/03 www.irf.com 111 PKG DESIG P PACKAGE T & R Orientation Fig A Feed Direction Figure A IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: (310) 252-7105 TAC Fax: (310) 252-7903 Visit us at www.irf.com for sales contact information Data and specifications subject to change without notice. 02/01