TelCom Semiconductor Inc TC38C43CPD, TC38C43CPA, TC38C43COE, TC28C43EPD, TC28C43EPA Datasheet

BiCMOS CURRENT MODE PWM CONTROLLERS

TC18C43

1

TC28C43
TC38C43

FEATURES

■ Low Power BiCMOS Design

■ Tough CMOS

■ 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 – 5 Volts

■ High Output Drive .................................... 0.7A Peak

■ 2 kV ESD Protection

■ Current Mode Control

■ Fast Rise/Fall Time (Max)...........60nsec @ 1000pF

■ High Frequency Operation ..........................500kHz

■ Clock Ramp Reset Current .................2.5mA ±10%

■ Low Propagation Delay Current Amp

to Output ............................................ 140nsec Typ.

■ Pin Compatible with UC3843

TM

Construction

(1.2A on 14-Pin and 16-Pin Versions)

ORDERING INFORMATION

Part No. Package Temperature

TC18C43MJA 8-Pin CerDIP – 55°C to +125°C
TC18C43MJD 14-Pin CerDIP – 55°C to +125°C

TC28C43EOE 16-Pin SOIC (Wide) – 40°C to +85°C
TC28C43EPA 8-Pin Plastic DIP – 40°C to +85°C
TC28C43EPD 14-Pin Plastic DIP – 40°C to +85°C

TC38C43COE 16-Pin SOIC (Wide) 0°C to +70°C
TC38C43CPA 8-Pin Plastic DIP 0°C to +70°C
TC38C43CPD 14-Pin Plastic DIP 0°C to +70°C

PIN CONFIGURATIONS

16-Pin SOIC (Wide)8-Pin Plastic DIP

1

CMPTR

2

V

I

SENSE

RT/C

FB

TC18CMJA
TC28CEPA

3

TC38CCPA

4

T

14-Pin Plastic DIP

CMPTR

114
213

NC

312

V

FB

411

I

SENSE

RT/C

NC

NC

TC18CMJD
TC28CEPD

510

TC38CCPD

69
78

T

TELCOM SEMICONDUCTOR, INC.

8
7
6
5

V

REF

V

IN

OUTPUT
GND

V

REF

NC
V

IN

V

DD

OUTPUT
GND

POWER
GND

NC

1

NC

2

CMPTR

3

V

4

FB

I

5

SENSE

RT/C

6

T

NC

7

NC

TC28CCOE
TC38CEOE

16

NC

15

V

REF

14

V

IN

13

V

DD

12

OUTPUT

11

GND
POWER

10

GND

98

NC

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 ampli­fier have been greatly improved over previous bipolar ver­sions. Voltage and temperature stability have been im­proved 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 (±10%) for
accurate dead time control. A few component values must
be changed (RT & CT) to use the TC38C43 in existing bipolar
designs.

The 14-pin DIP and 16-pin SOIC versions have sepa­rate and internally isolated grounds, and are rated for higher
output current (1.2A). These separate grounds allow for
‘bootstrap’ operation of the PWM to further improve effi­ciency.

FUNCTIONAL BLOCK DIAGRAM

R/TC

V

REF

S

R

V

UV GOOD

Q

REF

14

R

T

7

OSC

LIMIT BUFFER

1.4V

+
–

CLK

11

V

10

OUTPUT

8

POWER
GROUND

PIN NUMBERS FOR
14-PIN DIP

TC38C43-7 10/21/96

DD

4-93

ANALOG

GND

SENSE

V

COMP

V

IN

12

2.5V 1.4V

UNDER VOLTAGE

SECTION

9

PWM COMPARATOR

0.4V
+

– +

5

–

CLK

ERROR AMP

2.5V

+

FB

–

3

1

2R

2

3

4

5

6

7

8

TC18C43
TC28C43
TC38C43

BiCMOS CURRENT MODE

PWM CONTROLLERS

ABSOLUTE MAXIMUM RATINGS*

Supply Voltage ............................................................18V

Maximum Chip Temperature................................... 150°C

Storage Temperature ............................– 65°C to +150°C

Lead Temperature (Soldering, 10 sec) .................+300°C

Package Thermal Resistance

CerDip R
CerDip R

................................................ 150°C/W

θJ-A

.................................................. 55°C/W

θJ-C

PDIP R
PDIP R
SOIC R
SOIC R

Operating Temperature

18C4x ...................................... – 55C° ≤ TA ≤ +125°C

28C4x ........................................ – 40C° ≤ TA ≤ +85°C

38C4x ............................................. 0C° ≤ TA ≤ +70°C

................................................... 125°C/W

θJ-A

..................................................... 45°C/W

θJ-C

................................................... 250°C/W

θJ-A

..................................................... 75°C/W

θJ-C

ELECTRICAL CHARACTERISTICS unless otherwise stated, these specifications apply over specific

temperature range. VIN = V

Parameter Test Conditions Min Typ Max Min Typ Max Units
Reference Section

Output Voltage TA = 25°C, IO = 1mA 4.9 5 5.1 4.90 5 5.10 V
Line Regulation 9.5V ≤ V
Load Regulation 1mA ≤ lO ≤ 11mA — ±5 ±15 — ±3 ±10 mV
Temp Stability (Note 1) — ±0.25 ±0.5 — ±0.25 ±0.5 mV/°C
Output Noise Voltage 10Hz ≤ f ≤ 10 kHz,TA = 25°C (Note 1) — 100 — — 100 — µV(rms)
Long Term Stability TA = 125°C, 1000 Hrs. (Note 1) — ±0.5 — — ±0.5 — %
Output Short Circuit -20 -50 -100 -30 -50 -100 mA

Oscillator Section

Initial Accuracy TA = 25°C (Note 4) 90 100 110 93.8 100 106.5 kHz
Voltage Stability 9.5V ≤ VIN ≤ 15V — ±0.2 ±0.3 — ±0.2 ±0.3 %
Temp Stability T
Clock Ramp Reset RT/CT Pin at 4V 2.25 2.5 2.75 2.25 2.5 2.75 mA
Amplitude RT/CT Pin Peak to Peak 2.45 2.65 2.85 2.45 2.65 2.85 V
Maximum Freq Note 1 1 — — 1 — — MHz

Error Amp Section

Input Offset Voltage V
Input Bias Current (Note 1) — ±0.3 ±2—±0.3 ±2nA
A

VOL

Gain Bandwidth Product (Note 1) 650 750 — 650 750 — kHz
PSRR 9.5V ≤ VIN ≤ 15V 80 100 — 80 100 — dB
Output Sink Current VFB = 2.7V, V
Output Source Current VFB = 2.3V, V
V

High VFB = 2.3V, RL = 10k to Ground 5.65 6 6.5 5.65 6 6.5 V

OUT

V

Low VFB = 2.7V, RL = 10k to V

OUT

Rise Response Note 1 — 5 7 — 5 7 µsec
Fall Response Note 1 — 3 5 — 3 5 µsec

Current Sense Section

Gain Ratio Notes 2 & 3 2.8 2.9 3.1 2.8 2.9 3.1 V/V
Maximum Input Signal V
PSRR 9.5V ≤ VIN ≤ 15V (Notes 1, 2 & 5) 70 80 — 70 80 — dB
Input Bias Current Note 1 — ±0.3 ± 2—±0.3 ±2nA
Delay to Output V(I

= 15V; RT = 71 kΩ; CT = 150 pF.

DD

TC18C43
TC28C43 TC38C43

≤ 15V, IO = 1mA — ±3 ±10 — ±3 ±10 mV

IN

≤ TA ≤ T

MIN

= 2.5V — ±15 ±50 — ±15 ±50 mV

(CMPTR)

2V ≤ VO ≤ 4V 70 90 — 70 90 — dB

(CMPTR)

= 5V (Note 2) 0.85 0.95 1.05 0.85 0.95 1.05 V

= 1V (Note 1); Figure 3 — 140 160 — 140 150 nsec

SENSE)

(Note 1); Figure 2 — ±0.01 ±0.05 — ±0.01 ±0.03 %/°C

MAX

= 1.1V (Note 1) 1.2 1.5 — 1.5 1.7 — mA

(CMPTR)

= 5V (Note 1) 3 3.4 — 3.9 4.2 — mA

(CMPTR)

REF

0.1 0.7 1.1 0.1 0.7 1.1 V

4-94

TELCOM SEMICONDUCTOR, INC.

)

BiCMOS CURRENT MODE
PWM CONTROLLERS

TC18C43

TC28C43
TC38C43

ELECTRICAL CHARACTERISTICS (Cont): unless otherwise stated, these specifications apply over specified

temperature range. VIN = V

Parameter Test Conditions Min Typ Max Min Typ Max Units
Output Section

R

DS (ON) I

R

DS (ON) I
Rise Time CL = 1nF (Note 1) — 40 60 — 35 60 nsec
Fall Time CL = 1nF (Note 1) — 30 60 — 30 40 nsec
Cross Conduction In Coulombs (Note 1) — 6.5 — — 6.5 — nC
VDD Ma Note 1 — — 18 — — 18 V

Undervoltage Lockout Section

Start Threshold x8C43 7.9 8.4 8.8 7.9 8.4 8.8 V
Undervoltage Threshold x8C43 7.2 7.6 7.9 7.2 7.6 7.9 V

PWM Section

Maximum Duty Cycle x8C43 (Note 1) 95 97 100 95 97 100 %
Minimum Duty Cycle 0 0 %

Supply Current

Start Up TA = 25°C, VIN < VUV; Figure 1 50 170 300 50 170 300 µA
Operating VFB = V(I

NOTES: 1. These parameters, although guaranteed over the

TelCom Semiconductor reserves the right to make changes in the circuitry or specifications detailed in this manual at any time without notice. Minimums
and maximums are guaranteed. All other specifications are intended as guidelines only. TelCom Semiconductor assumes no responsibility for the use of
any circuits described herein and makes no representations that they are free from patent infringement.
*Static-sensitive device. Unused devices must be stored in conductive material. Protect devices from static discharge and static fields. Stresses above
those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only and functional operation of
the device at these or any other conditions above those indicated in the operational sections of the specifications is not implied. Exposure to Absolute
Maximum Rating Conditions for extended periods may affect device reliability.

recommended operating conditions, are not tested in
production.

2. Parameter measured at trip point of latch.

3. Gain ratio is defined as:

∆V

COMP

∆V(I

SENSE

= 15V; RT = 71 kΩ; CT = 150 pF.

DD

TC18C4X
TC28C4X TC38C4X

= 20mA — 7 15 — 7 15 Ω

SINK

= 20mA — 11 20 — 11 15 Ω

SOURCE

) = 0V; Figure 4 1 2 1 1.5 mA

SENSE

where 0 ≤ V(I

4. Output frequency equals oscillator frequency for the
x8C43.

5. PSRR of V
combination.

) ≤ 0.8V

SENSE

, Error Amp and PWM Comparator

REF

1

2

3

4

5

6

PIN DESCRIPTION

Pin No. Pin No Pin No
8-Pin 14-Pin 16-Pin Symbol Description

2 1 NC No Connection

4 2 NC No Connection
1 1 3 CMPTR Compensation of the feedback loop response.
234 VFBFeedback of voltage to error amplifier to regulate voltage.
355I

4 7 6 R

TELCOM SEMICONDUCTOR, INC.

SENSE

/C

T

T

For sensing pass transistor current and terminate drive when current
limit threshold is reached at this pin.

Capacitor and resistor input to set oscillator frequency of this PWM
controller. The resistor is connected from V
The capacitor is connected from RT/CT to ANALOG GND.

output to RT/C

REF

7

T.

8

4-95