Order this document by MC34129/D
High Performance
Current Mode Controllers
The MC34129/MC33129 are high performance current mode switching
regulators specifically designed for use in low power digital telephone
applications. These integrated circuits feature a unique internal fault timer
that provides automatic restart for overload recovery. For enhanced system
efficiency, a start/run comparator is included to implement bootstrapped
operation of VCC. Other functions contained are a temperature compensated
reference, reference amplifier, fully accessible error amplifier, sawtooth
oscillator with sync input, pulse width modulator comparator, and a high
current totem pole driver ideally suited for driving a power MOSFET.
Also included are protective features consisting of soft–start,
undervoltage lockout, cycle–by–cycle current limiting, adjustable deadtime,
and a latch for single pulse metering.
Although these devices are primarily intended for use in digital telephone
systems, they can be used cost effectively in many other applications.
•
Current Mode Operation to 300 kHz
MC34129
MC33129
HIGH PERFORMANCE
CURRENT MODE
CONTROLLERS
SEMICONDUCTOR
TECHNICAL DATA
14
1
P SUFFIX
PLASTIC PACKAGE
CASE 646
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Automatic Feed Forward Compensation
Latching PWM for Cycle–by–Cycle Current Limiting
Continuous Retry after Fault Timeout
Soft–Start with Maximum Peak Switch Current Clamp
Internally Trimmed 2% Bandgap Reference
High Current Totem Pole Driver
Input Undervoltage Lockout
Low Startup and Operating Current
Direct Interface with Motorola SENSEFET Products
Drive Output
Drive Ground
Ramp Input
14
1
D SUFFIX
PLASTIC PACKAGE
CASE 751A
(SO–14)
PIN CONNECTIONS
1
2
3
14 VCC
13 Start/Run Output
12 CSoft–Start
Feedback/
11 PWM Input
Error Amp
10
Inverting Input
9 Error Amp
Noninverting Input
8 Vref 1.25 V
(Top View)
Simplified Block Diagram
Start/Run
12
Soft–Start
and
Fault Timer
Undervoltage
Lockout
1.25V
Reference
Gnd
7
Error Amp
6
X2
Latching
PWM
RT/CT
Sync/Inhibit
Input
5
4
Oscillator
9 Noninverting
Input
+
10
–
Inverting
Input
11
Feedback/
1 PWM Input
Drive Out
2
Drive Gnd
3
Ramp Input
13
Start/Run
Output
VCC
Sync/Inhibit 4
Input
RT/CT 5
Vref 2.5 V
6
CSoft–Start
14
Gnd 7
8
Vref 1.25V
ORDERING INFORMATION
Device
MC34129D
MC34129P
MC33129D
MC33129P
Operating
Temperature Range
TA = 0° to +70°C
TA = – 40° to +85°C
Package
SO–14
Plastic DIP
SO–14
Plastic DIP
Rev 1
Vref 2.5V
©
Motorola, Inc. 1996
MOTOROLA ANALOG IC DEVICE DATA
1
MOTOROLA [ MOTOROLA, INC ]
