Document
ET-34063A
DC to DC Converter Control Circuits
DESCRIPTION
The MC34063A Series 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
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
ABSOLUTE MAXIMUM RATINGS
Rating Power Supply Voltage Comparator Input Voltage Range Switch Collector Voltage Switch Emitter Voltage (VPIN 1=40V) Switch Collector to Emitter Voltage Driver Collector Voltage Driver Collect Current (Note 1)
Switch Current Operating Junction Temperature Operating Ambient Temperature Range
Storage Temperature Range
Symbol VCC VIR
VC(switch) VE(switch) VCE(switch) VC(driver) IC(driver)
ISW TJ
TA
Tstg
Value 40
-0.3 to +40 40 40 40 40 100 1.5
+150
0 to +70
-65 to +150
Unit Vdc Vdc Vdc Vdc Vdc Vdc mA A
ET- 34063A
ELECTRICAL CHARACTERISTICS
(Vcc=5.0 V, Ta=Tlow to Thigh, unless otherwise specified.)
Characteristics
Symbol Min
OSCILLATOR
Frequency
fOSC 24
(Vpin5=0V, CT=1.0nF, TA=25 )
Charge Current (VCC=5.0V to 40V, TA=25 )
lchg 24
Discharge Current (VCC=5.0V to 40V, TA=25 )
ldischg
140
Discharge to Charge Current Ratio (Pin 7 to VCC, TA=25 ) ldischg/lchg 5.2
Current Limit Sense Voltage (lcha=ldischa; TA=25 )
Vipk(sence) 250
OUTPUT SWITCH (NOTE 2)
Saturation Voltage, Darlington Connection
(lSW=1.0A, Pins 1, 8 connected)
Saturation Voltage, Darlington Connection
(lSW=1.0A, Rpin8=82 to VCC, Forced
20)
VCE(sat) VCE(sat)
-----
DC Current Gain (lSW=1.0A, VCE=5.0V, TA=25 )
hFE 50
Collector Off-State Current (VCE=40V)
lC(off)
---
COMPARATOR
Threshold Voltage (TA=25 ) (TA=Tlow to Thigh)
Vth 1.225 1.21
Threshold Voltage Line Regulation (Vcc=3.0V to 40V) Input Bias Current (Vin=0V)
Regline lIB
-----
TOTAL DEVICE
Supply Current ( VCC=5.0V to 40V, CT=1.0nF, Pin 7= VCC , Vpin5>Vth, Pin2=Gnd, remaining pins open)
lCC
---
Type
33
35 220 6.5 300
1.0
0.45
75 40
1.25 --1.4 -20
---
Max
42
42 260 7.5 350
1.3
0.7
--100
1.275 1.29 5.0 -400
4.0
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.
Unit
kHz
A A --mV
V
V
--A
V
mV nA
mA
Ordering Info
Package DIP-8 SOP-8
ET34063
Package
Package: D: DIP-8 E: SOP-8
Packing type TB
Type ET34063D ET34063E
Packing type TB TB
.