A\LAMBDA SWITCHING REGULATORS LAS 6320P, 6321P 2 AMP SWITCHING REGULATORS FEATURES e DC to 100 kHz operation e Adjustable output voltage e Cycle-by-cycle current limit e Internal thermal shutdown @ Inhibit/enable control pin DESCRIPTION The LAS 6320P and LAS 6321P are monolithic integrated circuits designed for fixed frequency, pulse width modulated, switching converter applications such as step-down, step-up, flyback, forward, Cuk and voltage inverting DC-to-DC convert- ers and motor controls. The LAS 6320P, 6321P includes a temperature compen- sated voltage reference, sawtooth oscillator with over-current frequency shift, linear trailing edge pulse width mod- ulator with double pulse suppression logic, transconductance error amplifier, and a 2 amp Darlington output transistor with internal current limit protection. The LAS 6320P allows access to the refer- ence voltage; the LAS 6321P provides adjustable current limit. Both the LAS 6320P and LAS 6321P are available in a standard 14 lead plastic dual-in-line power package and are designed for mounting right on the printed circuit board. PARAMETER SYMBOL MAXIMUM UNITS Control Circuit Voltage Voc 35 Volts Output Collector Voltage Co 35 Volts Power Dissipation Py Internally Watts Limited Thermal Resistance Junction to Case uc 13 CW Thermal Resistance Junction to Ambient Bus 60 CW Operating Junction T and Storage Tempera- Te ~ 25 to 125 C ture Range s Lead Temperature (Soldering, 10 Theap 260 C Seconds) DEVICE CURRENT LIMIT REFERENCE LAS 6320P Fixed Accessible LAS 6321P Adjustable Not Accessible BLOCK DIAGRAM -E, +E Mier (LAS 6320P) CLS (LAS 6321P) 37LAS 6320P, 6321P ELECTRICAL CHARACTERISTICS Test conditions are as follows: Veg = 24V, Vo = SV, Ip = 2A, C, = 0.0056nF T, = 25C, unless otherwise specified. Test Conditions Test Limits Parameter Symbol Vec | lo | ty Minimum | Typical | Maximum | Units REFERENCE SECTION Reference Voltage Vaer 2.137 2.25 2.363 Volts Line Regulation REG ine) |12V to 30V 0.015 0.04 %IV Temperature Coefficient Te 0 to 125C 0.01 0.02 %/C OSCILLATOR SECTION Initial Frequency 33 +10 +33 % Accuracy Line Regulation of REG ine) | 12V to 30V 0.1 0.15 %/V Frequency Frequency Temperature To 0 to 125C 0.05 WlC Coefficient Sawtooth Duty Cycle d.c. 85 % ERROR AMPLIFIER SECTION Input Offset Voltage +5 mV Transconductance 2.7 mA/V Output Sink/Source 0.26 mA Current Input Common Mode 1.5 3.0 Volts Range Open Loop Voltage Gain 50 60 dB OUTPUT SECTION Peak Current let 2.2 2.8 3.5 Amps Limit Threshold Output Saturation Voltage | Vo (sat) | Co = Ver |0.5A 1.6 Volts Co = Voc 2A 2.1 2.3 Volts E, = GND |0.5A 0.9 Volts Eg = GND | 2A 1.4 1.6 Volts Efficiency n 70 75 % Current Rise Time tp Inductive Load 200 nS Current Fall Time te Inductive Load 200 ns CONTROL PIN Output Inhibit } | 0.64 0.75 1.06 Volts Quiescent Current lo Vo = OV 18 30 mA 38LAS 6320P, 6321P OPERATIONAL DATA POWER DERATING 5 c ty \. _ 4 \X oy % E Re, | % 3 g ON z 7 N% a 7) a a ON a 2 %, 4 a 1 ers, ye 0 0 25 50 75 100. 125 AMBIENT TEMPERATURE (C) POWER DISSIPATION EFFICIENCY VS 5 VS INPUT VOLTAGE 90 INPUT VOLTAGE 12V, 2A = 4 12V, 2A 85 e - 12V, 1A s | - z 3 ~ = 80 oO E Pp_| 5V, 2A 2 G Z 2 12V, 1A4 # 75 f ~ . = 5V, 1A & 1 | 70 0 65 5 10 15 20 25 30 5 10 15 20 25 30 INPUT VOLTAGE (VOLTS) INPUT VOLTAGE (VOLTS) FREQUENCY VS ERROR AMPLIFIER TIMING CAPACITANCE OPEN LOOP GAIN 200 100 100 80 80 60 40 3 g 60 20 z Ri 5 4 0 10 \ 8 6 20 \ 2 0 0.001 0.002 0.004 0.010 0.020 0.040 0.10 100 1K 10K 100K 1M 10M C, (uF) FREQUENCY (Hz) 39LAS 6320P, 6321P TYPICAL APPLICATIONS DC-TO-DC STEP-DOWN CONVERTER = +Nour +Vw ? rvyv* O Lt a75yH 18K 1.8K ow = of + Pis00 vsK340 7 000 pe oo 1K > GND GND Vin = 24V Vout = 5V @ 2A DC-TO-DC STEP-UP CONVERTER +My : rw. TH es oO Lt 375yH 12 o___, _| ul l TY vs 340 Veco Co GND E, CMP + fia} _frs}-_fis- i "}-_Jo] Ja + 15 LAS 6320P < Wee kL + k PW mis I. + Rt SCH = q 2roa | 0.047 0.22 a}, 1000 a7 047) Re Ls SENSE oo + 1 2h 3 pt 7 C; CNT GND Veet + Ere ~ En 0.047 i + 560 0.0047] Toze | a4 -0_-o__0 eo o e o ho GND Vin = 6V Vour = 12V @ 750mA All Capacitors in pF. 40LAS 6320P, 6321P DEVICE OUTLINE ) 0.255 Lo 0.245 0.065 0.060 sf 0.125 MIN | |l. oer MIN 100 go LAS 6320P LAS 6321P 7 Qo 44D Veo Vee cnt OQ 2 13D) Co Co 3 12 GNO| | 4 1 GND GND 5 10 Vee +En C6 9TE, Eo -&, 07 80 cmp CLS NOTE: All dimensions are in inches. 41