BiCMOS CURRENT MODE
PWM CONTROLLERS
TC18C43
TC28C43
TC38C43
1
ELECTRICAL CHARACTERISTICS
(Cont):
unless otherwise stated, these specifications apply over specified
temperature range. V
IN
= V
DD
= 15V; R
T
= 71 kΩ; C
T
= 150 pF.
TC18C4X
TC28C4X
Parameter
Output Section
R
DS
2
TC38C4X
Max
15
20
60
60
—
18
8.8
7.9
100
0
300
2
Test Conditions
I
SINK
= 20mA
I
SOURCE
= 20mA
C
L
= 1nF (Note 1)
C
L
= 1nF (Note 1)
In Coulombs (Note 1)
Note 1
x8C43
x8C43
x8C43 (Note 1)
Min
—
—
—
—
—
—
7.9
7.2
95
Typ
7
11
40
30
6.5
—
8.4
7.6
97
Min
—
—
—
—
—
—
7.9
7.2
95
Typ
7
11
35
30
6.5
—
8.4
7.6
97
Max
15
15
60
40
—
18
8.8
7.9
100
0
300
1.5
Units
Ω
Ω
nsec
nsec
nC
V
V
V
%
%
µA
mA
(ON)
R
DS (ON)
Rise Time
Fall Time
Cross Conduction
V
DD
Ma
Start Threshold
Undervoltage Threshold
3
4
5
6
7
Undervoltage Lockout Section
PWM Section
Maximum Duty Cycle
Minimum Duty Cycle
Supply Current
Start Up
Operating
T
A
= 25°C, V
IN
< V
UV
; Figure 1
V
FB
= V(I
SENSE
) = 0V; Figure 4
50
170
1
50
170
1
NOTES:
1. These parameters, although guaranteed over the
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
)
where 0
≤
V(I
SENSE
)
≤
0.8V
4. Output frequency equals oscillator frequency for the
x8C43.
5. PSRR of V
REF
, Error Amp and PWM Comparator
combination.
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.
PIN DESCRIPTION
Pin No.
8-Pin
Pin No
14-Pin
2
4
1
3
5
7
Pin No
16-Pin
1
2
3
4
5
6
Symbol
NC
NC
CMPTR
V
FB
I
SENSE
R
T
/C
T
Description
No Connection
No Connection
Compensation of the feedback loop response.
Feedback of voltage to error amplifier to regulate voltage.
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
REF
output to R
T
/C
T.
The capacitor is connected from R
T
/C
T
to ANALOG GND.
4-95
1
2
3
4
8
TELCOM SEMICONDUCTOR, INC.
TELCOM [ TELCOM SEMICONDUCTOR, INC ]
