TC18C43
TC28C43
TC38C43
BiCMOS CURRENT MODE PWM CONTROLLERS
FEATURES
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Low Power BiCMOS Design
Tough CMOS
TM
Construction
Low Supply Current ............. 1.0mA Typ @ 100kHz
Wide Supply Voltage Operation .............. 8V to 15V
Latch-Up Immunity ................... 500mA on Outputs
Input Will Withstand Negative Inputs to 鈥?5 Volts
High Output Drive .................................... 0.7A Peak
(1.2A on 14-Pin and 16-Pin Versions)
2 kV ESD Protection
Current Mode Control
Fast Rise/Fall Time (Max) ........... 60nsec @ 1000pF
High Frequency Operation ..........................500kHz
Clock Ramp Reset Current ................. 2.5mA
鹵
10%
Low Propagation Delay Current Amp
to Output ............................................ 140nsec Typ.
Pin Compatible with UC3843
1
GENERAL DESCRIPTION
The TC38C43 is a current mode BiCMOS PWM control
IC. With a low 1.0 mA supply current along with high drive
current (0.7A peak) it provides a low cost solution for a PWM
that operates to 500 kHz and directly drives MOSFETs up to
HEX 3 size.
Performance of the oscillator and current sense ampli-
fier have been greatly improved over previous bipolar ver-
sions. Voltage and temperature stability have been im-
proved by a factor of 3. Noise immunity (PSRR) has also
been improved.
The TC38C43 is pin compatible with the earlier bipolar
version so that designers can easily update older designs.
Improvements have been added, though. For example,
clock ramp reset current is specified at 2.5mA (鹵10%) for
accurate dead time control. A few component values must
be changed (R
T
& C
T
) to use the TC38C43 in existing bipolar
designs.
The 14-pin DIP and 16-pin SOIC versions have sepa-
rate and internally isolated grounds, and are rated for higher
output current (1.2A). These separate grounds allow for
鈥榖ootstrap鈥?operation of the PWM to further improve effi-
ciency.
FUNCTIONAL BLOCK DIAGRAM
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3
4
5
6
7
PIN NUMBERS FOR
14-PIN DIP
ORDERING INFORMATION
Part No.
TC18C43MJA
TC18C43MJD
TC28C43EOE
TC28C43EPA
TC28C43EPD
TC38C43COE
TC38C43CPA
TC38C43CPD
Package
8-Pin CerDIP
14-Pin CerDIP
Temperature
鈥?55擄C to +125擄C
鈥?55擄C to +125擄C
16-Pin SOIC (Wide) 鈥?40擄C to +85擄C
8-Pin Plastic DIP
鈥?40擄C to +85擄C
14-Pin Plastic DIP
鈥?40擄C to +85擄C
16-Pin SOIC (Wide)
8-Pin Plastic DIP
14-Pin Plastic DIP
0擄C to +70擄C
0擄C to +70擄C
0擄C to +70擄C
VIN
12
VREF
2.5V
1.4V
VREF
14
RT/CT
7
OSC
CLK
11
10
VDD
OUTPUT
POWER
GROUND
PIN CONFIGURATIONS
8-Pin Plastic DIP
CMPTR
VFB
ISENSE
RT / CT
1
2
3
4
8
VREF
VIN
OUTPUT
GND
7
6
5
16-Pin SOIC (Wide)
NC
NC
CMPTR
VFB
ISENSE
RT / CT
1
2
3
4
5
6
7
8
16
15
14
13
NC
VREF
VIN
VDD
OUTPUT
GND
POWER
GND
NC
UNDER VOLTAGE
SECTION
ANALOG
GND
9
UV GOOD
8
TC18CMJA
TC28CEPA
TC38CCPA
0.4V
SENSE
5 鈥?/div>
+
PWM COMPARATOR
+
S Q
鈥?/div>
CLK
R
TC28CCOE
TC38CEOE
12
11
10
9
14-Pin Plastic DIP
CMPTR
NC
VFB
NC
ISENSE
NC
RT / CT
1
2
3
4
5
6
7
14 VREF
13 NC
12 VIN
NC
NC
ERROR AMP
2.5V
VFB
3
COMP
1
R
+
鈥?/div>
2R
LIMIT BUFFER
+
鈥?/div>
1.4V
TC18CMJD
TC28CEPD
TC38CCPD
11 VDD
10 OUTPUT
9
8
GND
POWER
GND
8
TC38C43-7 10/21/96
TELCOM SEMICONDUCTOR, INC.
4-93
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