BiCMOS CURRENT MODE
PWM CONTROLLERS
1
2
3
4
5
6
7
8
TC18C43
TC28C43
TC38C43
ELECTRICAL CHARACTERISTICS (Cont): unless otherwise stated, these specifications apply over specified
temperature range. VIN = VDD = 15V; RT = 71 kΩ; CT = 150 pF.
TC18C4X
TC28C4X
TC38C4X
Typ
Parameter
Test Conditions
Min
Typ
Max Min
Max
Units
Output Section
RDS (ON)
RDS (ON)
ISINK = 20mA
—
—
—
—
—
—
7
15
20
60
60
—
18
—
—
—
—
—
—
7
15
15
60
40
—
18
Ω
Ω
ISOURCE = 20mA
CL = 1nF (Note 1)
CL = 1nF (Note 1)
In Coulombs (Note 1)
Note 1
11
40
30
6.5
—
11
35
30
6.5
—
Rise Time
nsec
nsec
nC
V
Fall Time
Cross Conduction
VDD Ma
Undervoltage Lockout Section
Start Threshold
x8C43
x8C43
7.9
7.2
8.4
7.6
8.8
7.9
7.9
7.2
8.4
7.6
8.8
7.9
V
V
Undervoltage Threshold
PWM Section
Maximum Duty Cycle
Minimum Duty Cycle
x8C43 (Note 1)
95
50
97
100
0
95
50
97
100
0
%
%
Supply Current
Start Up
TA = 25°C, VIN < VUV; Figure 1
170
1
300
2
170
1
300
1.5
µA
Operating
VFB = V(ISENSE) = 0V; Figure 4
mA
NOTES: 1. These parameters, although guaranteed over the
recommended operating conditions, are not tested in
production.
where 0 ≤ V(ISENSE) ≤ 0.8V
4. Output frequency equals oscillator frequency for the
x8C43.
2. Parameter measured at trip point of latch.
3. Gain ratio is defined as:
5. PSRR of VREF, Error Amp and PWM Comparator
combination.
∆VCOMP
∆V(ISENSE
)
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
Pin No
16-Pin
Symbol
Description
2
4
1
3
5
1
2
3
4
5
NC
NC
No Connection
No Connection
1
2
3
CMPTR
VFB
Compensation of the feedback loop response.
Feedback of voltage to error amplifier to regulate voltage.
ISENSE
For sensing pass transistor current and terminate drive when current
limit threshold is reached at this pin.
4
7
6
RT/CT
Capacitor and resistor input to set oscillator frequency of this PWM
controller. The resistor is connected from VREF output to RT/CT.
The capacitor is connected from RT/CT to ANALOG GND.
TELCOM SEMICONDUCTOR, INC.
4-95
TELCOM [ TELCOM SEMICONDUCTOR, INC ]
