7173

NTE7173
NTE7173SM
Integrated Circuit
1.5A Step−Up/Down Inverting
Switching Regulator
Description:
The NTE7173 and NTE 7173SM are monolithic circuits 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:
D Operation from 3V to 40V Input
D Low Standby Current
D Output Switch Current 1.5A
D Output Voltage Adjustable
D Frequency Operation to 100kHz
D Precision 2% Reference
Absolute Maximum Ratings:
Power Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Vdc
Comparator Input Voltage Range, VIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3 to +40Vdc
Switch Collector Voltage, VC(switch) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Vdc
Switch Emitter Voltage (VPin1), VE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Vdc
Switch Collector−to−Emitter Voltage, VCE(switch) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Vdc
Driver Collector Voltage, VC(driver) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Vdc
Driver Collector Current (Note1), IC(driver) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100mA
Switch Current, ISW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5A
Power Dissipation (TA = +25°C), PD
NTE7173 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.25W
NTE7173SM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625mW
Thermal Resistance, Junction−to−Ambient, RthJA
NTE7173 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +100°C/W
NTE7173SM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +160°C/W
Operating Ambient Temperature Range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0° to +70°C
Storage Temperature Range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65° to +150°C
Note 1. Maximum package power dissipation limits must be observed.
Electrical Characteristics: (VCC = 5V, TA = 0°C to +70°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Oscillator
Frequency
fOSC
VPin5 = 0V, CT = 1.0nF, TA = +25°C
24
33
42
kHz
Charge Current
lchg
VCC = 5V to 40V, TA = +25°C
24
35
42
µA
VCC = 5.0V to 40V, TA = +25°C
140
220
260
µA
Discharge to Charge Current Ratio ldischg/lchg Pin7 to VCC, TA = +25°C
5.2
6.5
7.5
−
Vipk(sense) lchg = ldischg, TA = +25°C
250
300
350
mV
Discharge Current
ldischg
Current Limit Sense Voltage
Output Switch (Note 2)
Saturation Voltage, Darlington
Connection
VCE(sat)
lSW = 1.0A Pin1 and Pin8 connected
−
1.0
1.3
V
Saturation Voltage
VCE(sat)
lSW = 1.0A, RPin8 = 82Ω to VCC,
Forced β ≅ 20, Note 3
−
0.45
0.7
V
hFE
lSW = 1A, VCE = 5V, TA = +25°C
50
75
−
−
VCE = 40V
−
0.01
100
µA
TA = +25°C
1.225
1.25
1.275
V
TA = 0° to +70°C
1.21
−
1.29
V
VCC = 5V to 40V
−
1.4
5.0
mV
lIB
Vin = 0V
−
−20
−400
nA
ICC
VCC = 5V to 40V, CT = 1nF,
Pin7 = VCC, VPin5 > Vth, Pin2 = GND,
remaining pins open
−
−
4
mA
DC Current Gain
Collector Off−State Current
lC(off)
Comparator
Threshold Voltage
VTh
Threshold Voltage Line Regulation
Input Bias Current
Regline
Total Device
Supply Current
Note 2. Low duty cycle pulse techniques are used during test to maintain junction temperature as close
to ambient temperature as possible
Note 3. If the output switch is driven into hard saturation (non−Darlington configuration) at low switch
currents (≤ 300mA) and high driver currents (≥ 30mA), it may take up to 2µs for it to come
out of saturation. Thi condition will shorten the off time at frequencies ≥ 30kHz, and is magnified at high temperatures. Thi condition does not occur with a Darlington configuration, since
the output switch cannot saturate. If a non−Darlington configuration is used, the following
output condition is recommended:
IC output
≥ 10
IC driver − 7mA *
* The 100Ω resistor is the emitter of the driver device requires about 7mA before the
* output switch conducts.
Forced β of output switch:
Pin Connection Diagram
Switch Collector 1
8 Driver Collector
Switch Emitter 2
7
Ipk Sense
Timing Capacitor 3
6
VCC
GND 4
5
Comparator Inverting Input
NTE7173
8
5
.256 (6.52) Max
1
4
.393 (10.0)
Max
.300 (7.62)
.150
(3.81)
.070 (1.77) Min
.100 (2.54)
.300 (7.62)
NTE7173SM
.192 (4.9)
8
1
.236
(5.99)
5
4
.154
(3.91)
.016
(.406)
.050 (1.27)
.061
(1.53)
.198 (5.03)
.006 (.152)
NOTE: Pin1 on Beveled Edge