DC-TO-DC CONVERTER CONTROL CIRCUITS
The SL34063A is a monolithic control circuit containing the primary functions required for DC-to-DC converters. These devices consist of an internal temperature compensated reference, comparator, controlled duty cycle oscillator with an active current limit circuit, driver and high current output switch. This series was specifically designed to be incorporated in Step-Down and Step-Up and Voltage-Inverting applications with a minimum number of external components.
FEATURES
FUNCTIONAL BLOCK DIAGRAM
? Operation from 3.0 V to 40 V Input ? Low Standby Current ? Current Limiting
? Output Switch Current to 1.5 A ? Output Voltage Adjustable
? Frequency Operation to 100 kHz ?
Precision 2% Reference
MAXIMUM RATINGS
Rating
Symbol Value Unit Power Supply Voltage
V CC 40 Vdc Comparator Input Voltage Range V IR -0.3 to +40 Vdc Switch Collector Voltage
V C(switch) 40 Vdc Switch Emitter Voltage (Vpin 1 = 40 V) V E(switch) 40 Vdc Switch Collector to Emitter Voltage V CE(switch) 40 Vdc Driver Collector Voltage
I C(driver) 40 Vdc Driver Collector Current (Note 1) I C(driver) 100 mA Switch Current
I SW 1.5 A Power Dissipation and Thermal Characteristics Ceramic Package, U Suffix T A = +25°C Thermal Resistance
Plastic Package, P Suffix T A = +25°C Thermal Resistance
SOIC Package, D Suffix TA = +25°C Thermal Resistance
P D R θJA P D R θJA P D R θJA 1.25 100 1.25 100 625 160 W °C/W W °C/W mW °C/W Operating Junction Temperature
TJ +150 °C Operating Ambient Temperature Range T A 0 to +70 °C Storage Temperature Range Tstg -65to+150 °C
SL34063A
SL34063A
ORDERING INFORMATION Device Temperature Range Package 34063AD 0° to +70°C SO-8 34063AP1 Plastic DIP
ELECTRICAL CHARACTERICISTICS
(V CC = 5.0 V, T A = 0 to +70o C unless otherwise specified.) Characteristics
Symbol
Min
Typ Max Unit OSCILLATOR
Frequency (V Pin 5 = 0 V, C T = 1.0 nF, T A = 25°C) fosc 24 33 42 kHz Charge Current (V CC = 5.0 V to 40 V, T A = 25°C) Ichg 24 33 42 μA Discharge Current (V CC = 5.0 V to 40 V, T A = 25°C) Idischg
140 200 260 μA Discharge to Charge Current Ratio (Pin7 to Vcc, T A =25°C) Idischg/Ichg 5.2 6.2 7.5 — Current Limit Sense Voltage (Ichg = Idischg, T A = 25°C) Vlpk(sense)
250 300 350 mV OUTPUT SWITCH (Note 3)
Saturation Voltage, Darlington Connection (I SW = 1.0 A, Pins 1, 8 connected)
V CE (sat) — 1.0 1.3 V Saturation Voltage (I SW = 1.0 A, R Pin 8 = 82 ? to V CC . Forced β = 20)
V CE (sat) — 0.45 0.7 V DC Current Gain (I SW = 1.0 A, V CE = 5.0 V, T A = 25°C) h FE 50 120 — — Collector Off-State Current (V CE = 40V) I C (off)
— 0.01 100
μA
COMPARATOR
Threshold Voltage (T A = 25°C) (T A = T LOW to T HIGH ) Vth
1.225 1.21 1.25 — 1.275 1.29
V Threshold Voltage (T A = 25°C) **
Vth
1.2375 1.25 1.2625 V Threshold Voltage Line Regulation (V CC = 3 0 V to 40 V) Regime 1.4 5.0 mV Input Bias Current (Vin=0V)
I IB
— -40 -400 nA TOTAL DEVICE
Supply Current (V CC = 5 0 V to 40 V, C T = 1 0 nF, V pin7 = V CC . V Pin5 > Vth, Pin 2 = Gnd, Remaining pins open)
I CC
2.5
4.0
mA
NOTES:
1. Maximum package power dissipation limits must be observed.
2.Low duty cycle pulse techniques are used during test to maintain Junction temperature as close to ambient temperature as possible
3.If the output switch is driven into hard saturation (non Darlington configuration) at low switch currents (< 300 mA) and high driver currents (>30 mA), it may take up to 2.0 μs to come out of saturation This condition will shorten the off' time at frequencies > 30 kHz, and is magnified at high temperatures This condition does not occur with a Darlington configuration, since the output switch cannot saturate If a non Darlington configuration is used, the following output drive condition is recommended
Forced β of output switch = I C , output/(Ic, driver -7.0 mA*) > 10
*The 100 ?. resistor in the emitter of the driver device requires about 7.0 mA before the output switch conducts **Possible version for shipment
Pin connection