MC34129EF Datasheet, PDF (1/16 Pages) Freescale Semiconductor, Inc – high performance current mode controllers

Freescale Semiconductor, Inc._{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
• 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
MC34129
MC33129
HIGH PERFORMANCE
CURRENT MODE
CONTROLLERS
SEMICONDUCTOR
TECHNICAL DATA
14
1
P SUFFIX
PLASTIC PACKAGE
CASE 646
14
1
D SUFFIX
PLASTIC PACKAGE
CASE 751A
(SO–14)
PIN CONNECTIONS
CSoft–Start ¹²
7
Gnd
6
Vref 2.5V
5
RT/CT
Sync/Inhibit ⁴
Input
Simplified Block Diagram
Soft–Start
and
Fault Timer
Start/Run
13 _Start/Run
Output
Undervoltage 14
Lockout
VCC
1.25V
Reference
8
Vref 1.25V
X2
Oscillator
Latching
PWM
Error Amp
9
+
–
10
Noninverting
Input
Inverting
11
Input
Feedback/
1 ^{PWM Input}
Drive Out
2
Drive Gnd
3
Ramp Input
Drive Output 1
Drive Ground 2
Ramp Input 3
Sync/Inhibit
Input
4
RT/CT 5
Vref 2.5 V 6
Gnd 7
14 VCC
13 Start/Run Output
12 CSoft–Start
Feedback/
11 _{PWM Input}
10
Error Amp
Inverting Input
9 ^{Error Amp}
Noninverting Input
8 Vref 1.25 V
(Top View)
ORDERING INFORMATION
Device
Operating
Temperature Range
Package
MC34129D
MC34129P
TA = 0° to +70°C
SO–14
Plastic DIP
MC33129D
TA = – 40° to +85°C
MC33129P
SO–14
Plastic DIP
© Motorola, Inc. 1996
MOTOROLA ANALOG IC DEVICEFDoArTMA ore Information On This Product,
Go to: www.freescale.com
Rev 1
1